5E.

Nervous System
I. Describe Nervous System and its types.
DIFFUSED CENTRALIZED
FEATURE
NERVOUS SYSTEM NERVOUS SYSTEM
Phylum Cnidarian (hydra) All other phylums
Ganglia  
Brain
 (A bilobed mass composed
of two ganglia is present in
anterior region of body)
Different neurons: Sensory, associative and
 Lack brain motor neurons are different
 No local clusters of neurons which are present in brain
Nerves  No differentiation of neurons and longitudinal, lateral
nerves.
Sensory→ message to brain
Motor→ message to body
Differentiation  
Impulse
Direction
 
Receptors  Eyes & chemo-receptors in
anterior region
Plexes (Nerve
Superficial Superficial + Deeper
Net)
GANGLIA Clusters of cell bodies of neurons in PNS
NUCLEI Clusters of cell bodies of neurons in CNS
NERVE Clusters of axons + dendrons in PNS
TRACT Clusters of axons + dendrons in CNS
PLEXES Network of neurons in PNS
Nervous System

CNS PNS

Brain Spinal Cord Motor Neurons Sensory Neurons

Autonomic NS Somatic NS

Para-Symphathetic
Symphathetic NS
NS
II. Explain Central Nervous System including forebrain, mid
brain, hindbrain and spinal cord.
CNS (CENTRAL NERVOUS SYSTEM)
Protected by:
1. cranium (protects brain and neural arches)
2. meninges (triple layered)
3. cerebrospinal fluid (CSF)
a. Simliar to blood plasma
b. Baths neurons of brain and spinal cord
c. Provide cushions against the bumps and jolts
d. Present in central canal of spinal cord and ventricles (cavities)
of brain and between meninges

BRAIN
BRAIN PARTS FUNCTIONS
Relay center for sensation from eye, skin & internal
Thalamus
receptors
 Hormone production
 Coordinating centre
 Control body temperature
Limbic Hypothalamus  Hunger
System  Menstrual cycle
(an arc  Water balance
between  Sleep-wake cycle
cerebral  Sensation of pleasure
thalamus and Amygdale  Punishment
cerebrum) (cluster of neurons)  Sexual arousal
 Feeling of fear and rage
FOREBRAIN

 Long term memory

Hippocampus
 Learning
 Cerebral  Receives sensory
Hemispheres information, processes it,
(two halves) stores it in form of short-term
 Corpus callosum memory
(large band of axons  Direct voluntary movement
due to which  Responsible for thinking
cerebral halves  Intelligence
Cerebrum communicate)  Reasoning
(Largest Part)  Convolutions  Judgment
(outer cerebral  Sensory area
cortex forming –  Motor area
increases surface  Right half = Left body (v.v.)
area)
 4 lobes
(Frontal, Occipital,
Parietal, Temporal)
  Relay center connection hindbrain with forebrain

BRAIN
MID Reticular  Screening input information
formation  Contains auditory relay station
 Center of great reflexes
Pons
 Influence transition between sleep and
(located
wakefulness
above
 Control rate
te and patterns of breathing
medulla)
HINDBRAIN

Control autonomic functions

 Breathing
Medulla
 Heart rate
oblongata
 Blood pressure
 Swallowing
Cerebellum  Coordinate voluntary move
(best  Guides smooth and accurate motion
developed in  Maintains body position and balance
birds)  Learning & Memory storage for behaviours
SPINAL CORD
SPINAL CORD (Large number of neurons + Cell fibres and bodies)
Cross section:  Center for
1. Inner butterfly shaped Gray matter (cell bodies + non many reflexes
myleniated nerve fibres or tracts) in central canal  Conduct
2. White matter ( myleniated nerve fibres or tracts) outer impulses

Posterior Part of Hind Brain = CEREBULLUM

Anterior Part of Hind Brain = PONS
Center of Great Reflexes = MID BRAIN + SPINAL CORD
Cerebral Nerves = CRANIAL NERVES

NERVES
SENSORY

CRANIAL MOTOR

REGIONAL MIXED

SPINAL MIXED
CLASSIFICATION
SENSORY

FUNCTIONAL MOTOR

MIXED

CRANIAL NERVES = 12 pairs = 24

SPINAL NERVES = 31 pairs = 62
TOTAL NERVES = 43 pairs = 86

BRAIN | SPINAL CORD

Outer Grey Matter | Inner Grey Matter
Inner White Matter | Outer White Matter

GRAY MATTER
Non-myleniated
myleniated nerve fibres or tracts + Cell bodies
WHITE MATTER
Myleniated
yleniated nerve fibres or tracts
III. Explain Peripheral Nervous System and its types (Autonomic
and Sympathetic).
PNS (PERIPHERAL NERVOUS SYSTEM)
PNS is composed of sensory and motor neurons forming ganglia.

SOMATIC SYSTEM (SNS) - voluntary

PART FUNCTIONS
Motor Control voluntary movements (under conscious control of
Neurons body) – skeletal muscles

AUTONOMIC SYSTEM (ANS) - involuntary

 Utilize 2 neurons and 1 ganglion for each impulse
 Limb movement is not in control of ANS
FEATURES SYMPATHETIC SYSTEM PARA-SYMPATHETIC SYSTEM
Arise from Middles portion of spinal Upper & Lower portion of
cord spinal cord
VAGUS NERVE (10th pair)
Ganglia Ganglia are close to spinal Ganglia are far away to
cord spinal cord
Control Controlled by Controlled by
 Throracic Part  Cervical Part
 Lumber Part  Pelvic Part
Functions 3F 3R
 Fear  Relax
 Fight  Rest
 Flight  Rumination
Pupil Dilates Constricts
Tear glands No effect Stimulates tear secretion
Salivary glands Inhibits saliva production Stimulates saliva production
Digestion Inhibited Promotion
Heart Beat Accelerated Retarded
Liver Stimulates glucose productionStimulates bile production
Bladder Inhibits urination Stimulates urination

IV. Describe neurons (Associative, Motor and Sensory

Neurons).

COMPOSITION OF HUMAN NERVOUS SYSTEM:

1. Neuroglia – 50%
a. Protected by myelin sheath
b. In CNS they are called Oligodendrites
c. In PNS they are called Schwann Cells

2. Neurons – 50%
a. Functional Unit of Nervous System
 b. Longest cells of body
c. Speed of neurons in PNS > CNS
d. Do not divide once mature
e. Regeneration of axons and dendrites can take place if cell
body is intact
f. Consists of
i. SOMA
A. Main nutritional part of cell
B. Concerned with biosynthesis of materials
necessary for growth and maintenance of neuron
C. Can regenerate axonal and dendrite fibres
D. Non-myleniated
ii. CYTOPLASMIC/PROTOPLASMIC PROCESSES
A. Axon
 Conduct impulse away from cell body
 More than 1 meter long
 Axoplasm (cytoplasm of Axon) contains
microtubules, neurofibrils, RER and
mitochondria throughout
B. Dendron
 Conduct impulse towards cell body
 Spiny look
C. Dendrites
 Dendrons in form of smaller fibers
 They are non-myleniated
 Control center containing nucleus
iii. NISSL’S GRANULES
A. Group of ribosomes associated with RER and
Golgi Apparatus
g. Have 3 functional types.
i. Sensory Neuron
ii. Associative/Immediate/Relay Neuron
iii. Motor Neuron

AXONS DENDRON/DENDRITES
Conduct impulse away from Conduct towards away from
cell body cell body
Smooth Surface Rough Surface (dendritic spines)
Generally only 1 axon per cell Usually many dendrites per cell
No ribosomes Have ribosomes
Can have myelin No myelin insulation
Branch away from cell body Branch near to cell body
 FEATURE SENSORY RELAY MOTOR
Other name Afferent Neurons Interneurons Efferent Neurons
Polarity Pseudou
Pseudounipolar Bipolar Multipolar
True dendrites
Dendrites Absent Absent
(short)
Present Present
Dendron Absent
(long) (short)
Present Present Present
Axons
(short) (short/long) (long)
Myleniation Always No Frequently
In Spinal Cord: In Spinal Cord:
Axon Entirely within the Dendrites
Location Out Spinal Cord: spinal cord or Cell body
Dendrites CNS Out Spinal Cord:
Cell
ell body Axon
Travel CNS to
Receptor to CNS CNS to CNS
Direction Effectors(muscles)
Receptors
eceptors such
Brain and spinal Central
entral nervous
Occurrence as the eyes, ears,
cord system (CNS)
tongue and skin

REFLEX ARC: (involuntary reflex action)

V. Describe nerve impulse and how it propagates.
Nerve Impulse:
 Wave of electrochemical changes travel along length of neuron
involving
i. Chemical reactions
ii. Movement of ions across the cell-membrane
 ELECTRIC POTENTIAL: Measure of capacity to do electrical work.
 MEMBRANE POTENTIAL: Electric Potential across cell membrane
i. RESTING MEMBRANE POTENTIAL
1. -70 mV or -0.07 V
2. Inside is more negative than outside
3. Concentration of Ions
a. Na+ = 10 times higher outside
b. K+ = 20 times higher inside
4. Channels
a. Pumps = Active Movement
b. Gates = Passive movement (Na+, K+)
5. Factors
a. Na+-K+ pump (3Na+ = 2K+) by active transport (ATPase)
b. Leakage of K+ ions to outside of cell by diffusion
c. Negative ions inside of cell (Organic acids, Proteins)
6. No conduction of impulse
7. Polarized state

ii. ACTION MEMBRANE POTENTIAL

1. +50 mV or +0.05 V
2. Inside is more positive than outside
3. Initiation of nerve impulse = Inward movement of Na+
4. Neurotransmitters
a. Inhibitory neurotransmitters
 Serotonin
 GABA
 Dopamine
b. Promotory neurotransmitters
 Dopamine
 Epinephrine
 Nor-epinephrine
5. Factors
a. Threshold stimulus
b. Na+ gates open
 Rapid Na+ movement to inside
 Some K+ movement to outside
c. Charge reversal
6. Conduction of impulse
7. Depolarized state…
 SALTATORY IMPULSE:
In myleniated neurons, impulse
hump from node to node (node of
Ranvier) called salutatory nerve.
Normal Impulse in humans = 100 ms-1
Max. Impulse recorder = 120 ms-1

VI. Understand the concept of synapse and passage of nerve

impulse, role of neurotransmitters.

SYNAPSE: Neurons communicate with one another at junctions

called synapses.
i. At a synapse, one neuron’s axon sends a message to a target neuron’s
dendrite.
ii. TYPES:
1. Chemical Synapse by chemical messengers neurotransmitters
 Used to jump action potential from one neuron to next in line
 Released at axon ending of neuron
 Neurotransmitters within brain or cord (CNS)
a. Adernaline (Epinephrine)
b. Nor-adernaline (Nor-epinephrine)
c. Serotonin
d. Dopamine
 Neurotransmitters out of CNS
a. Acetylcholine
2. Electrical Synapse directly by flow of ions

CHEMICAL SYNAPSE:
Synaptic knob  Synaptic vesicles fusion with presynaptic neuron’s membrane
 Release of neurotransmitters  Bind to receptors on the postsynaptic
neuron’s membrane  Fire an action potential.
 VII. Discuss the nervous disorders (Parkinson’s disease, Epilepsy
and Alzheimer’s disease).
NAME DEFINITION CAUSES TREATMENTS
 Cell death in area
Parkinson’s Characterized by that produce
 Effective drugs
Disease involuntary tremors, dopamine
(L- dopa)
(50-60 of diminished motor  Mental faculties –
 GDNF
age) power and rigidity not affected
 Head trauma
Characterized by
abrupt transient Alternations in brain
 Electroencepha
symptoms of motor, function associated
Epilepsy lography
sensory, psychic or with excessive rapid
(30 of age)  Anticonvulsant
autonomic nature electric discharges in
drugs
(changes in grey matter
consciousness)
 Dementia (memory
loss)
Alzheimer’s  Genetic pre-
Characterized by
Disease deposition
decline in brain Not available
(1907 Alois  High levels of
function
Alzheimer) aluminium
 Decline in brain
function
VIII. Understand the Biological Clock and Circadian Rhythms.
BIOLOGICAL RHYTHMS: Behaviour activities occurring at regular intervals
1. CIRCADIAN/DIURNAL RHYTHMS: 24 hours e.g. sleep-Wake
2. CIRCANNUAL RHYTHMS: 365 days e.g. Osterous Cycle
CAUSES:
1. Exogenous = External body factors/stimuli
2. Endogenous = Internal body factors/stimuli
3. Synchronization mechanism of exogenous + endogenous
Pinneal gland in humans give MALATONIN hormone controlling biorhythms
 IDENTICAL & FRATERNAL TWINS
FEATURE IDENTICAL TWINS FRATERNAL TWINS
Genetic Make up Identical Different
Cell Division Mitotically (Asexually) Sexually
Separation of
Formation of two
Production blasotomeres at two cell
different zygotes
stages

MALE AND FEMALE REPRODUCTIVE SYSTEM

MALE REPRODUCTIVE FEMALE REPRODUCTIVE
FEATURE
SYSTEM SYSTEM
Gonads Pair of testes Pair of ovaries
External
Pair of testes & scrotum Vagina
Genitilia
Seminiferous tubules
Oviduct
Epididymis
Duct System Uterus
Vas deferens
Vagina
Urethra
OOGENESIS
1…Oogonium (2n)
SPERMATOGENESIS
↓
1…Spermatogonium (2n)
Mitosis
↓
↓
Mitosis
1…Oogonia (2n)
↓
↓
1…Primary Spermatocyte
Cell Growth
(2n)
↓
↓
1…Primary Oocyte (2n)
Meiosis-I
Gametogenesis ↓
↓
Meiosis-I
2...Secondary
↓ ↓
Spermatocyte (n)
1...Secondary 1…First
↓
Oocyte (n) Polar Body
Meiosis-II
↓ (n)
↓
Meiosis-II
4…Spermatid (n)
↓ ↓
↓
1…Ovum (n) 1…Second
4…Sperm (n)
Polar Body
(n)
 SEXUALLY TRANSMITTED DISEASES (STDs)
Genital
FEATURE Gonorrhea Syphilis AIDs
Herpes
Causal Gram positive
Spirochete Virus Virus
Agent bacteria
Neisseria Treponema Herpes simplex
Cause HIV
gonorrhoeae pallidum type II
 Genitilia
 Mucous infection,
Damage to
membrane of  Genital
reproductive Destruction of
Main Parts urinogenital soreness &
organs, eyes, Immune
Affected tract ulcers
bones, joints, System
 Eye infection  Damage to
CNS, heart, skin
to baby eyes, CNS in
infants
Source of Sexual Sexual Sexual Sexual
Transmission Contact Contact Contact Contact
5G. Support & Movement
HUMAN SKELETON
i. Define and explain terminologies:
Bone, Cartilage, Tendon, and Ligament.

CONNECTIVE TISSUES
 Connective tissue serves a "connecting" function. It supports and
binds other tissues in the body.

Supporting Connective
Connectiv Tissues
 Endo skeleton is primarily
primarily made up of rigid connective tissues
1. Bones
2. Cartilage
 Living cells of endoskeleton (bones and cartilage) are embedded in
the protein matrix called COLLAGEN

ENDOSKELETON

Connective Tissue

Bones Cartilage

Osteoblast
Types Cells
Osteocyte
Compact Spongy
Bone Bone Osteoclast
 1. BONES:
a. Most rigid connective tissue
tiss
b. Collagen fibers hardened by Ca3(PO4)2 deposition
c. Structure:
i. Compact Bone:
 Dense, Strong outer shell
 Provides attachment site for muscles
ii. Spongy Bone:
 Light, Rich in blood vessels, Highly porous
 Cavities contain bone marrow where blood cells
are formed
d. There are 3 types of cells associated with bones
bones:
i. Osteoblast – Bone Forming Cells
ii. Osteocyte – Mature Bone Cells
iii. Osteoclast – Bone Dissolving Cells

Cartilage Osteoblasts
Osteclasts Bone
BONE FORMATION

2. CARTILAGE:
a. Much softer than bone, Connective Tissue
b. Living cells are called Chondrocytes.. They secrete elastic, non-
living matrix collagen surrounding them.
c. No blood vessels can penetrate into cartilage.
d. Types:
i. Hyaline cartilage
ii. Elastic cartilage
iii. Fibrous cartilage

FEATURE HYALINE FIBROUS ELASTIC

Abundance Most abundant Abundant Less abundant
Bluish white
Matrix Colour Dark yellow Yellow white
transparent
Chondroblasts
hondroblasts + Intracellular matrix
Structure Collagens
white collagens on net
net-like tissue
 Movement
 Strengthen  Support  Flexibility
Functions
respiratory tract  Protection  Support
 Bone Growth
 End of Movable
joints  Bone joints
 Pinnae of ears
Location  Bronchi, Larynx  Knee
 Epiglottis
 Tips of waist and  Back Bone
rib bones
Proper Connective Tissues
 They are of two types
a. Loose Tissues (Collagenous, Elastic and Reticular Fibers)
b. Dense Tissues (Tendons, Ligaments, Adipose tissues fibrils)

FEATURE TENDONS LIGAMENTS

Attachment Skeletal Muscle to Bone Bone to Bone
Elasticity Inelastic Elastic
Strength Tough Strong
Yellow elastic tissues +
Composition White fibrous tissues
Collagens
Structure Dense Parallel fibres Dense Non-Parallel fibres

ii. Describe Axial & Appendicular Skeleton.

S.No. PART BONE/COMPOSITION NUMBER TOTAL
AXIAL SKELETON - 80
1 Parietal bone 2
2 Temporal bone 2
3 Sphenoid bone 1
Skull (Cranium) 8
4 Occipital bone 1
5 Frontal bone 1
6 Ethmoid bone 1
7 Palatine 2
8 Maxilla 2
9 Lacrimal bone 2
10 Nasal bone 2
Skull (Facial) 14
11 Inferior concha 2
12 Zygomatic bone 2
13 Mandible 1
14 Vomer 1
15 Cervical (C1 to C7) 7 vertebrae
16 Thoracic (T1 to T12) 12 vertebrae
Vertebral
17 Lumber (L1 to L5) 5 vertebrae 33
Column
Pelvic (P1 to P9) 9 vertebrae
18
(Sacrum + Coccyx) (5+4)
10 pairs of Attaching
19 20
Rib Cage Ribs 24
20 2 pairs of Floating Ribs 4
21 Sternum Breast bone 1 1
APPENDICULAR SKELETON - 126
22 Scapula/Suprascapula 2
Pectoral Girdle 4
23 Clavicle 2
24 Humerus 2
25 Radius 2
26 Ulna 2
Fore Limbs 60
27 Carpals 16
28 Metacarpals 10
29 Phalanges 28
30 Pelvic Girdle Coxal bone 2 2
 31 Femur 2
32 Tibia 2
33 Fibula 2
Hind Limbs 60
34 Tarsals 16
35 Metatarsals 10
36 Phalanges 28
TOTAL BONES 206

INTERESTING INFORMATION

Human skeleton is both endoskeleton and exoskeleton (teeth).

Skull Cranium Bones – 8 (2)PT (1)SOFE
Skull Facial Bones – 14 (2)PMLN IZ (1)MV
Bone covering the teeth MAXILLA
Bone of eye ball LACRIMAL BONE
Cheek Bone ZYGOMETIC BONE
Inner nasal bone INFERIOR CONCHA
Lower jaw bone MANDIBLE
Mandible ONLY MOVEABLE BONE IN SKULL
Bones of upper buccal cavity PALATINE
Bone between 2 palatines
pa VOMER
Breast Bone STERNUM
Govilla Ribs FLOATING RIBS
Types of Ribs 3 (True, Floating, False)
Curvatures of Vertebrae PTCL (9+12+7+5)
1st Cervical Vertebra ATLAS (C1)
nd
2 Cervical Vertebra AXIS (C2)
Anterior Pelvic Vertebra SACRUM (P1 to P5)
Posterior
rior Pelvic Vertebra COCCYX (P6 to P9)
Bone not attached to any other bone
directly or upper part of trachea HYOID BONE
Ear has 6 bones (3 each) INCUS(2) – MALLEUS(2) – STAPES(2)
Parts of COAXIAL BONE (3) Fusion of ILIUM, ISCHIUM, PUBLIS
Shoulder bone SCAPULA
Collar Bone CLAVICLE
Arm Bone HUMERUS
Thigh Bone FEMUR
Tail Bone COCCYX
Knee cap PATELLA
Largest Bone in Human FEMUR
Smallestt Bone in Human STAPES
iii. Describe Joints and their types (fibrous, cartilaginous, synovial,
pivot and multistage).
JOINTS
 Studied under arthrology
 Occur where bones meet. Hold skeleton and also gives its mobility
 Types of Joints
a. FUNCTIONAL TYPES
i. Immovable joints
e.g. All Fibrous joints + Few Cartilaginous joints
ii. Slightly moveable joints
e.g. Few Cartilaginous joints
iii. Freely moveable joints
e.g. Synovial joints
b. STRUCTURAL TYPE
i. Fibrous joints
ii. Cartilaginous joints
iii. Synovial joints
FEATURE FIBROUS CARTILAGINOUS SYNOVIAL
 Have a cavity
filled wilth fluid
 Outer layer –
Held by short fibers coeective tissue
Structure embedded in United by cartilage – fibrous capsule
connective tissues  Inner layer –
synovial
membrane
 Have ligaments
Slightyly moveable
Movement Fixed - Immovable Freely moveable
or Immovavle
1. Hinge
2. Ball and Socket
 Sutures
 Synchondroses 3. Pivot
Types  Syndesmoses
 Symphses 4. Condyloid
 Gomphoses
5. Saddle
6. Planar
 Skull (cranial
 Hyaline cartilage
bones) Where great
in growing bones
 Tibia-fibula degree of
Occurence  Fibrous cartilage in
articulation immobility is
vertebra at front
 Teeth required
of pelvis
articulations

1. FLEXION Bending a joint – Counteraction of extension

2. EXTENISON Straightening a joint – Counteraction of flexion
3. ADDUCTION Parts of the body are drawn toward its axis
4. ABDUCTION Parts of the body are drawn away from its axis
5. CIRCUMDUCTION Conical movement – Combination of 1 to 4
6. ROTATION Movement around one axis
7. GLIDING Sliding movement
 1 2 3 4 5 6
JOINT TYPE DEFINITION MOVEMENT STRUCTURE EXAMPLES
 Elbow
Minimum
Like hinge of the Flexion  Knee
HINGE Flexible
door Extension  Fingers
Same plane
 Toes
Globular head Most Flexible
BALL & Circumduction  Shoulder
fixed in cup Perpendicular to
SOCKET Rotation  Hip
shaped cavity each other
 Atlas-Axis
Rotation around Parallel to one
PIVOT Rotation bones
a single axis another
 Radius-Ulna
 Wrist-MC-P
Multiple bones Different
CONDYLOID Circumduction joint
interaction directions
 MT-P joints
Opposite surfaces
Different  C-MC joint of
SADDLE are reciprocally Circumduction
directions the thumb
concave-convex
Allow gliding  Intercarpal
PLANAR Gliding One plane
movements only joints

MULTISTAGE JOINTS:
Saddle joints combine with condyloid joints to form compound joints called
multistage joints.
Example: Wrist Joints

MUSCULAR SYSTEM
i. Compare the types of muscles (smooth, cardiac and skeletal).
FEATURE SMOOTH CARDIAC SKELETAL
(Earliest form)
Other name Heart muscles -
Visceral muscles
Non-striped/ Irregular stripped/ Regular stripes/
Muscles
Non-striated Irregular striated Regular striated
Cell Shape Spindle/Long Branched Spindle/Cylindrical
Nucleus One per cell Many per cell Many per cell
Speed Slow Intermediate Slow to rapid
 Spontaneous
Contraction  Stretch
Spontaneous Nervous System
Cause  Nervous system
 Hormones
Transport in Hollow
Function Pumping of blood Moves the skeleton
Organs
Control Involuntary Involuntary Voluntary
Diameter 10 to 80 μm 1 to 5 μm ≈ 10 μm
ii. Explain structure and function of skeletal muscle.
SKELETAL MUSCLE FIBRE
Composed of Muscle Fibre and Cells
1. Long cylindrical Cell
2. Multiple Oval Nuclei
3. Sarcolemma
4. Huge cells
5. Diameter 10--100 µm
6. Sarcoplasm
Similar to cytoplasm but large amount of glycogen & myoglobin
myoglobin-
red O2 storing pigment
7. Large number of Myofibrils
Diameter 1-2 2 µm in parallel fashion and enclosed by sarcolemma
8. Sarcomere
Smallest contractile units of myofibrils/
myofibrils Region
on of myofibrils
between two successive Z-lines
Z
a) A Band – Series of Dark Band – Anisotropic i.e. polarizing
b) I band – Series of Light Band – Isotropic i.e. non-polarizing
polarizing
c) H-zone – lighter strip in mid section of A Band – H for hele i.e. bright
d) M-line – line bisecting H-zone
e) Z-line – mid line of I Band – Z for Zwishen
wishen i.e. between
9. Myofilaments
MYOFILAMENTS-ULTRA
ULTRA STRUCTURE
Made up of thick and thin filaments
1 Myosin filament = 6 Actin filaments
Feature Thick Filaments Thin Filaments
Occurence Extend across I-Band
Band & partly
Extend entire length
l of A Band
into A Band
Diameter 16 nm 7-8 nm
Composition Myosin 1. Actin
 Two globular heads Two chains twisted
 A tail (two long polypeptide 2. Tropomyosin
chains) Twisted around act
actin
 Cross bridges link thick and 3. Troponin
thin filaments 4. Three polypepetide comples
that binds to:
 Actin
 Tropomyosin
 Calcium ions
5. Receptors of cross bridges

Myosin + Tropomyosin = FIBROUS

Actin + Troponin = GLOBULAR
Skeletal Muscles = INNERVATED BY SNS NOT
DIRECTLY CONTROLLED BY CNS
iii. Explain the concept and working of sarcomere, ultrastructure
of myofilaments, sliding filament model.

SLIDING FILAMENT MODEL

DISCOVERY
H. Huxley and A. F. Huxley in 1954
MECHANISM
According to this model, there is certain degree of overlap between thick
and thin filaments.
During contraction:
 H zone – Disappears
 I band – Shortens
 A band – Unchange
 Sarcomere – Shorten
 Z line – Moves toward sarcomere
Actin molecules have special site with which heads of myosin can bind.
HOW THE BRIDGES ARE CONTROLLED?
1. Rest:
Muscle at rest → sites blocked by tropomyosin chains
2. Contraction:
Neuromuscular Junction → Motor Neuron/Nerves→ Motor Unit → T-
tubules → T-system → Sacroplasmic Reticulum(no ribosomes) → Release
Calcium ions → binds troponin → cause to move slightly → displace
tropomyosin → expose binding site for myosin → myosin being polar
attached → ATP (by mitochondria) hydrolyzed → cross bridges goes to
cycle → Muscle Contraction

ALL OR NONE RESPONSE

1. Muscle contraction follows all or none response. Upon arrival of impulse,
all fibrils of a cell contract together. Degree of contraction depends on
number of cells contracting at a time.
2. Rigor Mortis: ATP is required to break the cross-bridges. A contracted
muscle cannot relax in the absence of ATP. The amount of ATP is
depleted in the body after death. Under such circumstances, the cross-
bridges cannot be broken, and the body becomes stiff. This is
called rigor mortis (mortality=death).

iv. Understand the sources of energy for muscle contraction.

ENERGY FOR MUSCLE CONTRACTION

Normal Conditions Stressful Conditions (exercise)
Stored Glycogen in cell → Glucose 1. Creatine Phosphate → ATP
→ Aerobic Breakdown → ATP
2. Glucose → Lactic Acid →
Anaerobic breakdown → ATP
At rest:
Lactic Acid → 1/5 broken aerobically → energy → 4/5 Lactic Acid → Glucose

EFFECT OF EXERCISE ON MUSCLES

Regular exercise results in a number of changes in muscles:
1) Muscles themselves increase in size and strength
2) Muscles become more efficient and resistant to fatigue
3) Number of blood capillaries increase
4) Amount of stored glycogen & myoglobin also increase
5) Number of mitochondria in each cell also increase
Complete immobilization of muscle leads to weakness and
severe atrophy (degeneration of muscles).
MOVEMENT OF BONES
 Skeletal Muscles has three parts
a. ORIGIN: End of muscle which remains fix during contraction
b. INSERTION: End of muscle that moves the bone
c. BELLY: Thick part in b/w origin and insertion which contracts
  There are total 650 muscles
muscle in human body
 Antagonistic muscles are those which
which work against each other

EXTENSION/
MUSCLE ORIGIN INSERTION FUNCTION
FLEXION
Medical surface
BICEPS 2 heads of scapula Lifts radius Flexion
of radius
BRACHIALIS Humerus Ulna Lifts ulna Flexion
BRACHIO-
Humerus Radius Lifts radius Flexion
RADIALUS
2 heads from scapula Olecranon Straightens
TRICEPS Extension
and 1 from humerus process of ulna elbow

v. Describe Muscle Fatigue, Tetany, and Cramp with their causes.

# MUSCLE FATIGUE TETANY TETANUS CRAMPS

DEFINITION

Acute infectious
State of
Disease due to low disease caused by Titanic contraction
physiological
blood calcium anaerobic of entire muscle
inability to contract
bacterium

 Relative  Low blood sugar

deficiency of ATP level
 Ionic imbalance  Electrolyte
CAUSES

 Anaerobic
 Accumulation of  Low calcium depletion
bacterium
lactic Acid level in blood
bl  Dehydration
Clostridium tetani
 Low pH  Irritability of
 Glucose spinal cord and
breakdown neurons
 Painful spasm of
 Excitability of some skeletal
neurons muscles
 Loss of sensation  Stiffness of jaws Taut and painful
SYMPTOMS

 Muscle twitches and neck muscles mostly of

 Muscle muscles thigh and hip
 Muscle ache
convulsions  Rigidity of jaws muscle and lasts
 Spasm of larynx (lock jaw) for few seconds to
 Respiratory  Spasm of trunk several hours
paralysis and limb muscles
 Death  Respiratory
failure

DO YOU KNOW BUDDY?

APLASIA: Decrease in number of muscle cells

HYPERPALASIA: Abnormal increase in number of muscle cells
MUSCLE ATROPHY: Increase in size of muscles
5H. Hormonal Control
I. Describe hormones and their composition.

CHEMICAL COORDINATION
In animals;
 Endocrine system → endocrine glands → hormones(Greek exciting or setting in
motion)
 Endocrine system consists of some 20 glands

HORMONES
Definition:
Organic compounds released into blood into small amounts and transported
throughout the body to distant target cells where they initiate physiological
response.
Characteristics:
 Poured directly and transported to blood to respective target tissue
 Do not initiate new biochemical reactions but produce their effects by regulating
enzymatic and other chemical reactions, already present
 May either stimulate or inhibit the function
 Control long term changes i.e. growth rate, metabolic activity rate & sexual
maturity
Types:
(i) Proteins
 (insulin and glucagon) – Cannot enter the cell
(ii) Amino acids & derivatives
 (T3, T4, Melatonin, epinephrine & nor epinephrine)
(iii) Polypeptides
 (ADH, oxytocin, TSH, ACTH, Gonadotrophins, MSH, Calcitonin,
Parathormone, Secretin, Gastrin)
(iv) Steroids
 (oestrogens, testosterone, cortisone, progesterone, corticosterone,
aldosterone, ecdysone)

ENZYMES HORMONES
Proteins + RNA Protein + Lipids
Quick action Slow / Quick action
Short term effect Long term effect
Produce locally Produced by specialized cells
Intra/Extracellular Extracellular
High Molecular Weight Low Molecular Weight
Non-Diffusible Diffusible
May be reversible Always irreversible
Catalyst Regulator
II. Discuss the effect of hypothalamus on the pituitary gland.

HYPOTHALAMUS
1. Part of fore brain – Almond sized
Secretion Production Control Function
 Many sensory stimuli converted into hormonal
responses
ADH Sensory Stimuli and
 Secrete ADH & oxytocin that travel down the
& Neuro-secretory
nerves of posterior lobe of pituitary gland to be
Oxytocin cell
stored and released after receiving nerve impulses
from hypothalamus

III. Describe the knowledge of pituitary gland and its hormones.

Anterior lobe: Somatotrophin, Thyroid Stimulating Hormone,
i. Adrenocorticotropic Hormone, Gonadotrophins (Follicle
Stimulating Hormone (FSH), Luteinizing Hormone (LH),
Luteotropic Hormone (LTH), Prolactin).
ii. Posterior lobe: Vasopressin, Oxytocin.

PITUITARY GLAND or Hypophysis cerebri

1. Ovoid structure about 0.5 grams in adult
2. Connected to brain through short stalk called infundibulum
 3. Three lobes i.e.
A. Anterior Lobe – Master Gland (produces Primary + Tropic Hormones)
PRIMARY HORMONES TROPIC HORMONES
Act on other endocrine
Directly act on cells
glands
All hormones of anterior
lobe are primary except Prolactin
prolactin
Secretion Production Control Function Disorders
 Controls growth
1. Gigantism
 Promotes protein
STH Excess during early life
SRF synthesis throughout
(Somatotrop 2. Acromegaly
(Somatotrophin the body when
hin Excess during later life
Releasing Factor) growth has mostly
Hormone) 3. Dwarfism
ceased after
Under secretion
adolescence
 Controls thyroids
TRF
 When thyroxin is low in blood it is produced in
TSH (Thyrotrophin
excess and vice versa
(Thyroid Releasing Factor)
 Secreted throughout life but increased during
Stimulating – controlled by
period of rapid growth & development
Hormone) thyroxin level in
 Directly acts on thyroid glands to increase its
blood
number and secretory activity
CRF
ACTH
(Corticotrophin
(Adreno-
Releasing Factor)
corticotrop
– controlled by
hic  Control of adrenal Disturbance of normal
steroids level in
Hormone / cortex adrenal function
blood and direct
Corticotrop
stimulation by
hic
hypothalamus as
Hormone)
result of stress
GH (Gonadotrophic Hormones)
a. FSH
 Female: follicle development & estrogen secretion
(Follicle
LHRF  Male: development of germinal epithelium of testis
Stimulating
& sperm production
Hormone)
b. Female:
LH
(Luteinising
 Female: lutenisation, estrogen secretion, ovulation,
Hormone)
maintenance of corpus luteum (with prolactin),
Male: ICSH LHRF
progesterone secretion
(Interstitial
 Male: testosterone secretion
Cell
Stimulating
Hormone)
Production:
c. Prolactin
Pituitary Gland
/ LTH
Inhibition:  Along with LH maintains and stimulates
(Luteotrop
Prolactin progesterone and milk production
hic
Inhibiting Factor
Hormone)
(PIF)
B. Median Lobe
Production
Secretion Function Disorders
Control

MSH  Stimulation of melanocytes

Addison’s Disease
(Melanophore External to produce brown pigment,
Excess MSH causing skin
Stimulating light melanin, which darkens the
darkening
Hormone) skin

C. Posterior Lobe
Secretion Production Control Function Disorders

1. Concentrated Urine
1. Decrease in BP,
Increase levels cause
blood volume,  Controls levels of
increased water
ADH osmotic pressure of water in body by
reabsorption from distal
(Antidiuretic blood (detected by affecting
ends
Hormone) / osmo- receptors in reabsorption of
2. Diabetes Insipidus
Vasopressin hypothalamus) distal parts of
Lack of hormone
2. External Sensory nephron
causing dilute urine and
Stimuli
great thirst

Distention of cervix,
 Contraction of
decrease in
sooth muscles of
progesterone level
uterus during
Oxytocin in blood, neural
childbirth and milk
stimuli during
ejection from
parturition &
mammary glands
suckling

IV. Explain the hormones of thyroid and parathyroid: Thyroxin (T3,

T4), Calcitonin, Parathormone.

THYROID GLAND
1. One of largest endocrine glands
2. In mammals it consists of two lobes situated below larynx
3. Active continuously but produces higher levels of secretions during periods of rapid
growth and sexual maturation and in stress situations such as cold and hunger
Production
Secretion Function Disorders
Control
 Increase basic 1. Graves’ Disease
Tetraiodo- TSH metabolic rate (by Excess thyroxin with
thyonine (Thyroid stimulating breakdown exophtahlimic goiter
(T4) Stimulating of glucose, heat release (protruding of eyes),
/ Thyroxin Hormone) and ATP generation) increase basal metabolic
 Increase Growth (with rate, cardiac failure (if
 STH) prolonged)
 Differentiation of brain 2. Cretinism
cells Lack of thyroxin
 Metamorphosis in abnormal development,
amphibians (if less than short stature, coarse scanty
tadpole lava grow to hairs, thick yellowish scaly
Tri-iodo large sized tadpole skin, mentally retarded, fail
thyronine instead to to develop sexually
(T3) metamorphose into 3. Myxoedema
frog) Under secretion, iodine
shortage, swelling of neck
(goiter), excess fat, increase
weight, puffiness of
hands/skin, all bodily/mental
processes retarded

Production
Excess or deficiency leads
High Ca++ in  Increase Ca++ level in
to disturbance of calcium
blood blood by mineralization
Calcitonin metabolism with affect on
Inhibition:  Work antagonistically to
nerves, skeleton, blood
Low Ca++ in Parathormone hormone
muscle etc
blood

PARATHYROIDS
A. Embedded in posterior pat of lateral lobes of thyroid
Production
Secretion Function Disorders
Control

Parat- 1. Under Activity

Production
hormone Drop in Blood Ca++ ions which
Low Ca++ in  Decrease of Ca++ level
(from leads to muscular tetany
blood in blood
posterior and 2. Over-Activity
Inhibition:  Work antagonistically
lateral sides Progressive demineralization
of thyroid
High Ca++ in to Calcitonin hormone
of bones (rickets) as well as
hormone) blood
formation of kidney stones

V. Discuss the adrenal gland in detail:

i. Adrenal cortex
(cortisol, corticosterone, aldosterone, androgens).
ii. Adrenal medulla (adrenaline and nor adrenaline).

ADRENALS
1. Pair present, one on top of each kidney
2. Adrenal Medulla: inner layer –
(I) epinephrine (adrenaline) (II) nor-epinephrine (non-adrenaline)
Adrenal Cortex: outer layer – corticosteroids
(I) Cortisol, (II) Corticosterone (III) Aldosterone (IV) Androgens
 Production
Secretion Function Disorders
Control
 Vasodilatation (skeletal
muscles)
 Increase in cardiac output
Rarely in excess causes
Adrenaline /  Release of glucose from
abnormal high blood
Epinephrine glycogen
pressure
 Reinforcing sympathetic
Rats:
system
Stress Adrenal Medulla
 Increase in blood pressure
removed surgically, the
 Vasoconstriction (Gut)
ability to withstand any
 Release of glucose from
Non-adrenaline stress situation is markedly
glycogen
/ Nor- diminished (Cold)
 Reinforcing sympathetic
epinephrine
system
 Increase in blood pressure
Increase in blood glucose1. Addison’s Disease
level mainly by its Destruction of adrenal
Cortisol
production from protein cortex causing
(Gluco-)
and by antagonizing insulin
 metabolic disturbance
action  muscle action weakness
Corticosterone Increase in blood glucose loss of salts
(Gluco- and  stress conditions lead to
level and regulates mineral
Mineral-) ion balance collapse and death
ACTH 2. Cushing’s Disease
Conserves the level of Na+
 too much cortical
Aldosterone ions in body by preventing
hormones is produced
(Mineral-) their loss from kidney
 excessive protein
tubules
breakdown
 muscles & bones
Development of secondary weakness
Androgens
male characters  disturbs metabolism in
diabetes

VI. Explain hormones of Islets of Langerhans i.e. Insulin, Glucagon.

ISLETS OF LANGERHANS (PANCREAS)

1. Under control of pituitary trophic harmonic STH & ACTH, respond directly to level
of blood glucose
2. β- cells : associated with insulin production – larger in number (70%)
α- cells: associated with glycogen production – smaller in number (20%)
Delta cells and Epsilon cells: (10%)
Production
Secretion Function Disorders
Control

STH,  Increases breakdown of Rare tumours causing over

ACTH & glycogen and fats to secretion which leads to high
Glucagon blood glucose blood glucose level and
glucose  Works antagonistically with damage of α-cells and β-
level insulin cells.
 1. Diabetes Mellitus
Insulin inhibits glycogen
hydrolysis in liver;
 High blood sugar level
 High urine sugar level
 Body osmotic equilibrium
 Decreases blood glucose disturbance
STH,
level by converting into  Derangement of nervous
ACTH &
glycogen, lipids & proteins system
Insulin blood
 Increase utilization and  Accumulation of toxic
glucose
decrease hydrolysis of metabolites
level
glycogen  Body becomes dehydrated
2. Hypoglycaemia
Excess insulin production,
there is utilization of too
much sugar & its falls which
upsets nerve & muscle
functioning

VII. Describe the hormones of alimentary canal (Gastrin,

Secretin).

GUT
Production
Secretion Function
Control
Due to protein
Gastrin
food by mucosa stimulates secretion of gastric juice
in pyloric region
Acidic food in stimulates secretion of pancreatic juice & bile from
Secretin
duodenum pancreas & liver

VIII. Discuss the hormones of ovaries and testes (oestrogen,

progesterone, testosterone).

GONADS
A. Ovaries
Production
Secretion Function Disorders
Control
 Development of secondary
sexual characters in female
 Thickening of uterine wall
Oestrogen
during menstrual cycle
(ripening Deficiency causes
 Exerts a positive feedback at
follicles / failure to mature
FSH a point during estrous or
interstitial sexually in young and
menstrual cycle
cells of sterility in adult
 Rise in LH
ovary)
 Healing & repair of uterine
wall after menstruation
 Protein provision to embryo
  Inhibits FSH secretion
 Inhibits follicle ripening,
thickening & vasculariation
Progesterone
of uterus
(ruptured LH
 Maintains pregnancy
follicle)
 Suppresses ovulation
 Major constituent of birth
control pill

B. Testes (Interstitial Cells)

 Development of sex organs Castration before

Testosterone in foetus puberty leads to
ICSH (LH)  Development of sexual failure of secondary
17 β-hydroxy characters in adult sexual characters with
testosterone  Sex drive female appearance

IX. Explain the disorders of endocrine gland i.e. diabetes

mellitus, diabetes insipidus, goiter, dwarfism, gigantism.

DIABETES MELLITUS
Insulin inhibits glycogen hydrolysis in liver;
 High sugar level in blood and urine
 Body osmotic equilibrium disturbance
 Derangement of nervous system
 Accumulation of toxic metabolites and Loss of metal ions
 Dehydration

DIABETES INSIPIDUS
Lack of Anti-diuretic (vasopressin) hormone causing dilute urine and great thirst

GOITER
Swelling of neck due to under secretion of T3 or T4 hormones
 Iodine shortage
 Eyes protruding
 Excess fat
 Increase weight
 Puffiness of hands/skin
 All bodily/mental processes retarded

GIGANTISM
Excess secretion of Somatotrophin (Growth) Hormone during early life

ACROMEGALY
Excess secretion of Somatotrophin (Growth) Hormone during later life

DWARFISM
Under secretion of Somatotrophin (Growth) Hormone
 Nature of Hormones
SR. NAME OF HORMONE NATURE
ATURE
NO.
1 STH Protein
2 TCH Protein
3 ACTH Polypeptide
GnRHs
 FSH
4 Protein
 LH/ICSH
 Prolactin
5 MSH Polypeptide
6 ADH Polypeptide
7 Oxytocin Polypeptide
8 T3 and T4 Amino Acids
9 Calcitonin Polypeptide
10 Parathormone Protein
11 Insulin Protein
12 Glucagon Protein
13 Epinephrine Amino Acids
14 Nor-epinephrine
epinephrine Amino Acids
15 Cortisol Steroid
16 Corticosterone Steroid
17 Aldosterone Steroid
18 Androgens Steroid
19 Gastrin Polypeptide
20 Secretin Polypeptide
21 Oestrogen Steroid
22 Progesterone
esterone Steroid
23 Testosterone Steroid
24 17 β-hydroxy
hydroxy testosterone Steroid

INTERESTING INFORMATION

Number of thyroid gland ONE in humans

Number of lobes in thyroid gland TWO
Tetraiodo-thyonine
thyonine (T4) INACTIVE FORM of THYROXINE
Tri-iodo
iodo thyronine (T3) ACTIVE FORM of THYROXINE
PINNEAL GLAND (epiphysis cerebri)
It is a small, pine cone resembling endocrine gland in the epithalamus,
near the center of human brain, between the two hemispheres which
produces hormone melatonin that modulates sleep patterns in both
circadian and seasonal cycles.
cycl
6. Bioenergetics
A. Describe photosynthetic pigments (chlorophyll and
carotenoids).

Structure of Chlorophyll a, b
I. HEAD
a. Hydrophilic
b. C35H31
c. Porphyrin ring
i. Central
Magnesium
ii. 4-Pyrolle Rings

II. TAIL
a. Hydrophobic
b. C20H39O
c. Phytol
i. Hydrocarbons

Feature CHLOROPHYLL A CHLOROPHYLL B

Primary Photosynthetic Accessory Photosynthetic
Definition
Pigment Pigment
Functional Group -CH3 -CHO
Molecular Formula C55H72O5N4Mg C55H70O6N4Mg
Colour Blue green Yellow green
All plants, algae and Green algae and plants
Occurrence
cyanobacateria (embryophytes)
Energy Absorption 670 nm 640 nm
From the wavelength of blue- From the wavelength of
Energy Source
violet & orange-red light green light
Colours of Photosynthetic Pigments
 Reflected colours are visible while absorbed
absorbed ones are not visible.
 Energy transfer Carotenoids  Chlorophyll b  Chlorophyll a
 Accessory pigments protect human eye

PHOTOSYNTHETIC
PIGMENTS

Chlorophylls Carotenoids (accessory)

1. Chlorophyll a 1. Carotenes
2. Chlorophyll b 2. Xanthophylls
3. Chlorophyll c
4. Chlorophyll d
5. Bacteriochlorophylls

NAME COLOUR REFLECTED COLOUR ABSORBED

Chlorophylls Green, Yellow, Indigo
Green Violet-Blue
Blue and Orange
Orange-Red
Chlorophyll a Blue-green
green
Chlorophyll b Yellow
Yellow-green
Cartenoids Yellow
Yellow-orange / Red-orange Blue-Violet
Violet Range strongly
Carotenes Red-orange
orange
Xanthophylls Yellow
Yellow-orange

B. Understand the concept of absorption and action spectra.

Action Spectrum
um by T.W. Engelmann (Spirogyra)
The first action spectrum was obtained by German biologist, T.W. Engelmann in 1883.
He worked on Spirogyra.
Relative Absorption

Oxygen using Bacteria

Filament of
Green Algae
(Spirogyra)

Violet Blue Green Yellow Orange Red

400 450 500 600 650 700

Wavelength (nm)
Absorption Spectrum of Chlorophyll & Carotenoids
It indicates that absoprtion is;
(a) Maximum in blue and red parts of the spectrum.
i. Chlorophyll a has peaks at 430 and 670 nm.
ii. Chlorophyll b has peaks at 470 and 640 nm.
iii. Caretenoids have different absorption peaks.
(b) Minimum in other parts.

Action Spectrum for Photosynthesis

Relative Absorption

Violet Blue Green Yellow Orange Red

400 450 500 600 650 700

Wavelength (nm)

Feature ABSORPTION SPECTRUM ACTION SPECTRUM

How much light is Effectiveness of colours in
Shows
absorbed? photosynthesis
Allll the pigments (Chl a. b,
Shown by Only
nly chlorophyll a
carotene and xanthophylls)
Peaks Low High
Valleys Wide Narrow
Efficiency Less More
DO YOU KNOW BUDDY?
If equal intensities of light are given more photosynthesis will be
in: RED LIGHT
If unequal intensities of light are given more photosynthesis will
be in: BLUE LIGHT
 C. Discuss light dependent stage (cyclic and non-cyclic
phosphorylation).

Overview of photosynthesis

6CO2 + 12H2O Reactants

C6H12O6 6H2O 6O2 Products

PHOTOSYNTHESIS

Light Dependent Reactions Light Independent Reactions

(Energy Conversion) (Energy Conservation)

ATP and NADPH formation Formation of Carbohydrates

from H+ and 2e- of H20 from CO2 and, ATP and
formed from photolysis NADPH from LDRs

Difference between Light Dependent &

Independent Reactions
Light Dependent Light Independent (Dark)
Reactions Reactions
The reactions that require direct These reactions require no light
Definition involvement of light energy and energy directly. Bit indirectly they
light-absorbing pigments. use light
Area of
Thylakoids/Grana of chloroplasts Stroma of chloroplasts
Occurrence

Energy Energy Conversion Energy Conservation

Uses the energy from the high-
Uses low-energy electron carriers
Source of energy electron carriers created in
and converts the particles into
Energy the light-dependent reaction to
high-energy electron carriers
create CHOs.
Reactants H2O , ADP, NADP+ and Sunlight ATP, NADPH, CO2

Carbohydrates (Sugars), ADP,

Products ATP, NADPH, O2↑
NADP+

Speed Instantaneous speed Slow speed

 Photosynthesis Antenna Complex Structure

Light Harvesting Photosystem Primary Electron

Electron Transfer Acceptor
Photon Reaction Center

Chlorophyll - a

e-

Transfer
Antenna
of energy
Pigment
Molecules

PHOTOSYSTEM
(Light trapping systems)

Antenna Complex Reaction Center

1. Chlorophyll a 1. Chlorophyll a (1 or
2. Chlorophyll b more)
3. Carotenoids 2. Primary electron
acceptor
3. Associated ETC
electron carriers

1. ETC play an important role in formation of ATP by chemiosmosis.

2. Light energy absorbed by pigment molecules of antenna complex is transformed
ultimately to the reaction center and converted into chemical energy.
 PHOTOSYSTEM

PHOTOSYSTEM-I PHOTOSYSTEM
PHOTOSYSTEM-II

It has chlorophyll a molecule, It has chlorophyll a molecule,

which absorbs maximum light which absorbs maximum light
of 700 nm and is called P700. of 680 nm and is called P680.

Phosporylation

Phosphorylation
ADP + P = ATP

Mitochondria Cytoplasm Chloroplast

Oxidative Substrate level Photo

Photo-
Phosphorylation Phosphorylation Phosphorylation

Cyclic Non
Non-Cyclic
Phosphorylation Phosphorylation

PS-I PS-II and PS

PS-II
ATP ATP & NADPH2
No Oxygen release Oxygen release

DO YOU KNOW BUDDY?

Removal of Electrons OXIDATION
Addition of Electron REDUCTION
Plastoquinone is oxidized by TWO CYTOCHROME
CYTOCHROMES COMPLEX
Plastoquinone is reduced by PRIMARY ELECTRON ACCEPTOR

In cyclic
Ferredoxin is oxidized by: phosporylation
A) NADP+ reductase C) Plastocyanin D is correct
B) Primary Electron Acceptor D) Cytochrome Complex while for non-
cyclic A is
correct
 Non-Cyclic Phosporylation

i. Z-Scheme (Six Steps process)

1. Excitation of Photosystem II – P680
2. Photolysis (water splitting) – In lumen of thylakoids
H2 O ⇌ 2H+ + 2e– + ½ O2
(ETC II) (P680) (into air)

3. Electron Transport Chain – I

 Plastoquinone (Pq) = Have quinine
 Two Cytochromes Complex = Have iron
 Plastocyanin (Pc) = Have Copper

4. ATP generation by chemiosmosis

5. Excitation of Photosystem I – P700
6. Electron Transport Chain – II
 Ferredoxin (Fd) = Have iron
 NADP+ reductase
NADP+ reductase Coenzyme NADP
2H+ + 2e– ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ H2 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ NADPH2
(Photolysis) (P700)

ii. Passage of electrons

Photosystem-II  Primary Electron Acceptor  Pq  Two Cytochrome Complex 
Pc  Photosystem -I  Primary Electron Acceptor  Fd  NADP+ reductase
 Cyclic Phosporylation

i. Stimulus
1. Low ATP
2. NADPH accumulation in
chloroplast
ii. ATP generation is done by
chemiosmosis
iii. There is no release of oxygen
or NADPH
iv. Only ATP formation

v. Passage of electrons

Primary
Photosystem
Electron
I (P-700)
Acceptor

Plastocyanin Ferredoxin

Two
Cytochrome
Complex

Non-Cyclic Cyclic
Feature
Phosporylation Phosporylation
Definition Long Pathway Short Circuit
Electrons Not reused Reused
First Electron
Water P700 (PS-I)
Donor
Photosystems Photosystem I and II Photosystem-I
Last Electron
NADP+ P700 (PS-I)
Acceptor
Net Products ATP, NADPH and O2 ATP only
Under low ATP and high NADPH
Process Normal
stimulus
Oxygen Released Not released
Chemiosmosis
Chemiosmosis is the movement of ions across a semipermeable membrane, down
their electrochemical gradient e.g. generation of ATP by the movement of hydrogen
ions across a membrane during cellular respiration or photosynthesis.
 Concentration of H+ ions is high due to:
1. Active pumping across membrane
2. Splitting of water molecule
D. Discuss light independent stage (Calvin cycle).

Calvin Cycle

3CO2 + 9ATP + 6NADPH2 ⎯⎯ (CH2O)3 + 9ADP + 9Pi + 6NADP + 3H2O

PHASES
The Calvin cycle refers to the light independent reactions in photosynthesis
reactions in photosynthesis that take place in three key steps. Although the Calvin
Cycle is not directly dependent
ndent on light, it is indirectly dependent on light since the
necessary energy carriers (ATP & NADPH) are products of light-dependent
light dependent reactions.
1. Carbon Fixation:
Light-independent
independent reactions are initiated; CO2 is fixed from an inorganic to an
organic molecule.
2. Reduction:
ATP and NADPH are used to reduce 3PGA into G3P; then ATP and NADPH are
converted to ADP and NADP+, respectively
3. Regeneration of CO2 acceptor:
RuBP is regenerated, which enables the system to prepare for more CO2 to be
fixed.

DO YOU KNOW BUDDY?

 Highly reactive phosphorylated 5-carbon
5 carbon sugar
RIBULOSE BISPHOSPHATE (RUBP)
(R
 RuBP is catalyzed by enzyme
RIBULOSE BISPHOSPHATE CARBOXYLASE (Ru (Rubisco)
 Most abundant protein in chloroplasts and on Earth
RIBULOSE BISPHOSPHATE CARBOXYLASE (Rub (Rubisco)
 Other names of Light Independent Reactioons
CALVIN CYLCE – C3 PATHWAY – DARK REACTIONS
E. Describe the respiration at cellular level including:
● Glycolysis (with preparatory and oxidative phase), Kreb’s
cycle (with reference to production of NADH, FADH and ATP),
Electron Transport Chain with its carriers.
● Anaerobic Respiration and its types (alcoholic and lactic
acid fermentation).

RESPIRATION
i. Universal process by which organism breakdown complex compounds
ii. Types
1. External respiration
Exchange of respiratory
respiratory gases between organism and environment
2. Internal respiration
Better known as cellular respiration
CELLULAR RESPIRATION
i. Process by which energy is made available to cell in step by step breakdown
of C-chain
chain molecules in cells
ii. Most common fuel is GLUCOSE
GLUC
iii. Glucose is split into pyruvic acid prior entering into mitochondria. This is called
glycolysis. It takes place in both aerobic and anaerobic respiration.
2NAD 2NADH2

C6H12O6 ⎯⎯ 2C3H4O3 + Energy

(Glucose) (Pyruvic Acid)
iv. Types
1. Aerobic respiration
Respiration taking place in presence of oxygen
C6H12O6 + 6O2 ⎯⎯ 6CO2 + 6H2O + 2900 kJ/mol
2. Anaerobic respiration
Respiration taking place in absence of oxygen
i. ALCOHOLIC FERMENTATION
ii. LACTIC ACID FERMENTATION
FERMEN
 ANAEROBIC RESPIRATION
FEATURE ALCOHOLIC FERMENTATION LACTIC ACID FERMENTATION
Muscle cells of human and
 Primitive Cells
Occurrence animals during extreme physical
 Some eukaryotic cells as yeasts
activities as sprinting
Energy
Very small amount Very small amount
Utilized
ATP formation 2% of glucose into ATP 2% of glucose into ATP

2NADH2 2NAD 2NADH2 2NAD

Reaction 2C3H4O3 ⎯⎯ 2C2H5OH + 2CO2 2C3H4O3 ⎯⎯⎯⎯⎯ 2C3H6O3

(Pyruvic Acid) (Ethyl Alcohol) (Pyruvic Acid) (Lactic Acid)

AEROBIC RESPIRATION
C6H12O6 + 6 O2 + 6 H2O + 38 ADP +38 P  6 CO2 + 12 H2O + 38 ATP + 420 Kcal

STEPS OXYGEN SITE OF OCCURRENCE

Glycolysis Independent Cytoplasm

Pyruvate
Dependent Mitochondrial Matrix
Oxidation

Kerbs Cycle Dependent Mitochondrial Matrix

Electron Transport Inner membrane of

Dependent
Chain Mitochondria (Cristae)

For 1 glucose molecule

STEPS TIMES
Glycolysis 1
Pyruvate Oxidation 2
Kerbs Cycle 2
Electron Transport Chain 12
1. GLYCOLYSIS
i. Splitting of sugar in cytoplasm
ii. No oxygen required i.e. occurs in both aerobic and anaerobic respiration
iii. It has 2 phases
1. Preparatory phase – 1 time
2. Oxidative phase – 2 times
iv. ATP and NADPH production
1. Preparatory phase – 2 ATP utilized
2. Oxidative phase – 4 ATP produced + 2 NADH produced
3. Net ATP produced = 2
v. 1 time it produces
i. ATP = 2
ii. NADH = 2
iii. FADH2 = 0
iv. CO2 = 0
1. Preparatory Phase – (1 time)
Conversion
onversion of glucose to glyceraldehyde 3 – phosphate via phos
phosphorylation.

ENZYMES
1. Hexokinase
Phosphorylates
hosphorylates the glucose
molecule to form glucose 6 –
phosphate.
2. Phosphohexose Isomerase
Helps
elps convert glucose 6 –
phosphate to fructose 6 –
phosphate.
3. Phosphofructokinase
fructokinase – 1
Most
ost important enzyme in
terms of regulatio
regulation.
4. Aldolase
Helps split the 6 carbon sugar
phosphate to form the 3
carbon sugar phosphates.
5. Triosephosphate
hosphate Isomerase
Converts
onverts DHAP molecule into
G3P molecule.

2. Payoff/Oxidative Phase – (2 times)

Conversion
onversion of G3P to pyruvate via oxidation and the formation of both ATP and
NADH

ENZYMES
6. Glyceraldehyde 3 – phosphate
dehydrgenase
Catalyzes
atalyzes the oxidation of the
aldehyde group to a carboxylic
group and phosphorylates the
G3P to 1,3 – BPG
7. Phosphogylcerate kinase
1,3 BPG loses a phosphate
group which is transferred to an
ADP molecule to form ATP
8. Phosphoglycerate mutase
Phosphate
hosphate group on carbon 3 is
removed and the one on
carbon 2 remains.
9. Enolase
Dehydrogenation
ehydrogenation occurs.
10. Pyruvate kinase
Form
orm ATP when converting PEP
to pyruvic acid.
2A. PYRUVATE OXIDATION
i. Conversion of pyruvate in to acetyl co-A in mitochondrial matrix
ii. It runs for 2 times for 1 glucose molecule
iii. 1 time it produces
 ATP = 0
 NADH = 1
 FADH2 = 0
 CO2 = 1
iv. ENZYMES
 Pyruvate Decarboxylase
 Pyruvate Dehydrogenase

2B. KREBS CYCLE

i. Also called citric acid cycle or tri-carboxylic acid cycle.
ii. Entrance of pyruvate in form of acetyl co-A
iii. It runs for 2 times for 1 glucose molecule
iv. It utilizes 3 water molecules
v. ATP is indirectly generated during phosporylation of GDP to GTP
vi. 1 time it produces
 ATP = 1
 NADH = 3
 FADH2 = 1
 CO2 = 2
3A. ELECTRON TRANSPORT CHAIN
i. System where electrons are transported in series of oxidation-reduction steps
to react ultimately, with molecular oxygen
ii. It runs for 12 times for 1 glucose molecule
iii. Sequence of electron flow:
Coenzyme Q  Cytochrome b  Cytochrome c  Cytochrome a  Cytochrome a3
3B. OXIDATIVE PHOSPORYLATION
PHOSP
i. Syntheis of ATP in presence of oxygen
ii. Coupled with respiratory chain
NADH + H+ + 3ADP + 3Pi + ½O2 ⎯⎯ NAD+ + H2O + 3ATP
iii. In oxidative phosphorylation
phosphory
 1 NADH = 3 ATP
 1 FADH2 = 2 ATP
CALCULATIONS
STEPS ATP NADH FADH2 CO2
Glycolysis x 1 4x1 2x1 - -

Pyruvate Oxidation
dation x 2 - 1x2 - 1x2
Kerbs Cycle x 2 1x2 3x2 1x2 2x2

Total 6 10 2 6
6x1 10 x 3 2x2
ATP CALCULATION 6 30 4 -

40

i. Total ATP produced = 40

ii. Net ATP produced in eukaryotes = 36
 2 utilized in glycolysis
 2 utilized in NADH pumping
iii. Net ATP produced in prokaryotes = 38
 2 utilized in glycolysis

INTERESTING INFORMATION

High level of NADH2 in pyruvate PYRUVATE DECARBOXYLA

CARBOXYLASE
oxidation INHIBITED
Shortcut to remember Krebs Cycle OFFICER! CAN I KILL
ILL
SOMEONE FOR MONEYONEY
Activates phosphofructokinase
phosphofruc LESS AMOUNT OF CITRATE
Inhibits phosphofructokinase
phosphofruc HIGH AMOUNT OF ATP
Oxidation EVERY NEXT MEMBER OXIDIZES
THE PRIOR ONE
Reduction EVERY MEMBER REDUCED
THE NEXT ONE
 TEST YOUR SELF

Q.1 Oxidative phosphorylation, Q.8 The terminal electron acceptor in

synthesis of ATP in the presence of electron transport chain is
oxygen occurs in: A) Hydrogen
A) All Types of Cells B) Iron
B) All Anaerobic Cells C) Cytochrome
C) All Primitive Cells D) Oxygen
D) All Aerobic Cells
Q.9 The end product of glycolysis is
Q.2 Glycolysis is the breakdown of A) ADP
glucose into two molecules of B) Reduced FAD
A) Glycerate C) Citric acid
B) Lactic Acid D) Pyruvate
C) Pyruvate
D) Succinic Acid Q.10 One molecule of FADH2 is
produced in Krebs’s cycle during
Q.3 Before entering Krebs’s cycle, the conversion of
pyruvate is first decarboxylated A) Fumarate Malate
and oxidized into B) Succinate Fumarate
A) α-Ketoglutaric
Ketoglutaric Acid C) Malate Oxaloacetate
B) Citric Acid D) α-Ketoglutarate
Ketoglutarate Succinate
C) Glyceric Acid
D) Acetic Acid Q.11 Every molecule of NADH, fed into
Q.4 Some electron from the second ETC produces:
primary acceptor may pass back A) 2 ATP
to chlorophyll molecules by B) 3 ATP
electron carrier system, yielding C) 4 ATP
ATP. This process is called D) 6 ATP
A) Phosphorylation
B) Photophosphorylation
phosphorylation Q.12 Final acceptor of electrons in
C) Non-Cyclic
Cyclic Phosphorylation respiratory chain is:
D) Cyclic Phosphorylation A) Cytochrome a
B) Oxygen
Q.5 Z-scheme
scheme is used for C) Cytochrome a3
A) Non-Cyclic
Cyclic Photophosphorylation D) Cytochrome c
B) Cyclic Photophosphorylation
C) Both A and B Q.13 The endnd product of anaerobic
D) Oxidative Phosphorylation respiration in humans and other
mammals is:
Q.6 The product(s) of cyclic A) Pyruvic acid
photophosphorylation
rylation is / are: B) Ethanol
A) ATP C) Lactic acid
B) NADP D) Glucose
C) NADP and ATP
D) NADP, ATP, and O2 Q.14 A biochemical process which
occurs within a cell to breakdown
Q.7 Total NADH formed by one glucose complex compounds to produce
molecule during Krebs’s Cycle are energy is called:
A) 6 A) Respiration
B) 3 B) Photosynthesis
C) 8 C) Oxidation reduction
D) 18 D) Photophosphorylation
Q.15 Which part of chlorophyll molecule Q.22 In glycolysis, glycerate-1,3-
absorbs light? bisphosphate is converted into
A) Phytol glycerate-3-phosphate by losing
B) Porphyrin ring _____________ phosphate
C) Pyrrole molecules.
D) Thylakoid membrane A) 3
B) 2
Q.16 Oxidative phase of glycolysis starts C) 1
with dehydrogenation of D) 4
A) Glycolysis
B) Ribulose Bisphosphate Q.23 Malate is oxidized by _______ to
C) Glyceraldehyde 3-phosphate oxaloacetate in Krebs’s Cycle.
D) NADH A) ATP
B) NADP
Q.17 In one turn, the Krebs’s cycle C) NAD
produces one molecule of ATP, D) FAD
one molecule of FADH2 and
__________ molecules of NADH Q.24 In electron transport chain, the
A) 1 electrons from NADH and FADH2
B) 2 are passed to;
C) 3 A) Cytochrome a
D) 4 B) Cytochrome a3
C) Co-enzyme c
Q.18 Which one of the following is the D) Co-enzyme Q
stage of cellular respiration for
which oxygen is not essential? Q.25 Carriers of the respiratory chain are
A) Glycolysis located on:
B) Pyruvate oxidation A) Matrix of mitochondria
C) Krebs’s cycle B) Outer mitochondrial membrane
D) Electron Transport Chain C) Inner mitochondrial membrane
D) Cytoplasmic matrix
Q.19 Pyruvate, the end product of
glycolysis moves from cytosol to
mitochondrial matrix where it is Q.26 Each _____ consists of a light
oxidized into _______ producing gathering antenna complex and
CO2 as a by-product. reaction center.
A) Acetic acid (active) A) Chlorophyll
B) Citrate B) Photosystem
C) NAD C) Photon
D) FAD D) Electron

Q.20 Pyruvate Acetyl CoA Q.27 Photosystem I has chlorophyll a

molecules which absorb maximum
? ? light of:
A) 680 nm
A) FAD+ FADH B) 780 nm
B) NAD+ NADH C) 700 nm
C) NADH  NAD + H+ D) 580 nm
D) FADH+ FAD + H+
Q.28 Cyclic flow or C4 photosynthesis
Q.21 In light independent stage of produces:
photosynthesis, the CO2 combines A) ATP and CO2
with _______ to form an unstable 6- B) ATP
carbon intermediate. C) Only CO2
A) Ribulose bisphosphate D) Only Oxygen
B) Hexose sugar
C) Glycerate-3-phosphate
D) Glyceraldehyde-9-phosphate
Q.29 Immediate product formed after Q.30 Functional group of chlorophyll a
CO2 fixation in Calvin Cycle is: is:
A) Unstable 6-carbon compound A) —CH3
B) Unstable 5-carbon compound B) —CHO
C) Unstable 4-carbon compound C) —COOH
D) Unstable 3-carbon compound D) —OH

Q.1 C Q.11 B Q.21 A

Q.2 C Q.12 B Q.22 C
Q.3 D Q.13 C Q.23 C
Q.4 D Q.14 C Q.24 D
Q.5 A Q.15 B Q.25 C
Q.6 A Q.16 C Q.26 B
Q.7 A Q.17 C Q.27
C
Q.8 D Q.18 A Q.28 B
Q.9 D Q.19 A Q.29 A
Q.10 B Q.20 B Q.30 A
8. Ecosystem
A. Define succession and describe various stages of xerosere.

Succession
1. Succession is sequence of events in community structure of ecosystem over
period of time.
a. PIONEERS: Succession begins by a few hardly invaders
b. CLIMAX COMMUNITY: Diverse and stable community at the end
2. Types:
a. PRIMARY SUCCESSION:
Succession starting from bare rock san or clear glacial pool where there
is no trace of previous life.
b. SECONDARY SUCCESSION:
Development of new ecosystem after an existing ecosystem is disturbed
by forced fire or an abandoned farm field.
3. Primary Succession Types:
a. Hydrosere:
Primary succession starting in pool is called hydrosere. Such plants are
called hydrophytes.
b. Xerosere:
Primary succession starting on dry soil or habitat is called xerosere. Such
plants are called xerophytes. Such plants withstand prolonged periods
of water shortage. Succulent plants like cacti have water stored in large
parenchyma cells.
XEROSERE
DESCRIPTION
STAGE
 Crust is external protective surface
 Crustose means crusts on substratum
 Special types lichen gets impregnated in lichen form.
Crustose
 Live in extreme conditions
lichen stage
 Surface is wet due to rain and dew drops
 Quiescent or dormant
 Normally desiccated(dried) during dry season so absorb water
 Licjens are just like crumbled leaves attached at one point
 Provides shades to crustose lichen and reduce their growth
Foliage lichen
 Area become rough with more and more fissure , depressions
stage
 Soil is more porous with litter of lichens
 EXAMPLES: (a) DERMATOCARPON (b) PERMELLIA
 Compete with lichen for water
 Penetrate much deeper into soil than lichens
Moss stage
 Add more humus to soil
 EXAMPLES: (a) POLYTRICHUM (b) TORTULA
Herbaceous  Small seedlings of herbaceous plants establish
stage  More availability of moisture, humus and soil for anchorage
 Shrubby plants started growing
Shrub stage
 Herbaceous plants die due to shadows and add humus to soil
 Woody plants develop due to improved soil
Climax stage
 Remains same throughout except change is surrounding happen
B. Describe the significance of human activity on ecosystem
such as Population, Deforestation, Ozone Depletion,
Greenhouse Effect, Acid rain, Eutrophication and Pesticides.

Population
Demography:
Demography is the study of human populations and things that affect them.
Population of Pakistan:
The population of Pakistan was 32.5 million at time of independence in 1947. It has
now increased to 150 -160 million people in year 2000. In view of limited resources
available and necessity of our learning how we will manage our resources is a
question.
Population Explosion:
About 20 years ago the human population was increasing at the rate of 2% a year
and was doubling every 35 years thus increasing demands for food, space and
other resources.
There are various factors affecting population growth, such as,
i. Increase in life expectancy due to better living conditions
ii. Education
iii. better food
iv. medicine
Reasons for world population explosion:
i. Disease prevention medicine, public, personal and food hygiene.
ii. Improved nutrition by efficient agriculture.
iii. Housing and improved living standards
iv. Child care, maternity, parent- craft and welfare services.
Consequences of Population Increase:
i. Overcrowding, less living space more people more crime, violence and social
diseases.
ii. Starvation through lack of sufficient food.
iii. Populations will outstrip food supply.
iv. Destruction of the countryside, plants, and animals and wildlife.

Deforestation
Clearance of vast areas of forest for procuring lumber, planting crops or grazing
cattle is called deforestation leading to desertification.
AFFORESTATION REFORESTATION
Establishment of new forests
Replanting in forests where
where no forests existed
forests existed previously.
previously.
Primary Succession Secondary Succession
 Forests are environmental buffers because they break speed of wind, rain and
floods.
 Forest has great importance in the environment of human. It is important
because it provide.
i. Timber – construction wood for houses
ii. Fire wood
iii. Medicine (herbal medicine, wax, honey) and many other products
 About half of rain which falls in tropical forests comes from transpiration of trees.
 Biodiversity refers to total number of different species with in an ecosystem and
resulting completely of interaction among them.
Ozone Depletion
1. Ozone (O3) is a form of oxygen gas.
2. Self replenishing gas
3. In this molecule three atoms of oxygen are bounded together.
4. It is a layer of atmosphere extending from 10-50 kilometers above earth, which
filters most of ultraviolet radiations and protects us from it. This is called ozone
layer.
5. In pure form ozone is bluish explosive and highly poisonous gas.
6. A single molecule can destroy 1 million ozone molecules.

Causes:
The main cause of ozone depletion is increase of chlorofluorocarbon (CFCs) which
contains chlorine, fluorine and carbon. These are chemicals that are largely used in
cooling systems (refrigerators air conditioners) and extinguishers etc. The CFCs is
percolating up through atmosphere and reducing O3 to O2 i.e. destroying the ozone
layer.

Harmful effects:
i. The layer of ozone is becoming thinner and the holes are appearing on it due
to pollution therefore more ultra violet rays are reaching on earth.
ii. The level of ozone in the ozone layer above Antarctica has fallen drastically
and has led to a hole. The ozone layer has also been found to decrease over
arctic regions.
iii. If this depletion of ozone continues then more ultraviolet rays will affect all life
on earth by increase in temperature, cancers and cataracts in human. It can
also affect crops, plants, trees and even marine plankton and it will destroy
weather pattern.

Green House Effect

Greenhouse has many glass windows through which light rays from sun penetrate
inside and absorbed by plants and soil and then reradiate as longer wave infra red
radiation. The glass does not allow these rays to escape outside and so heat remains
within green house.

Role of Carbon Dioxide:

The role of carbon dioxide is same as that of glass sheet of green house. Carbon
dioxide absorbs the energy of sun but do not allow it to escape outside as result of
which the temperature of atmosphere increases. This increase in while temperature
and it is known as green house effect.

Global Warming – Cause of Greenhouse Effect:

The causes of green house effect are increasing rate of the people migrating
towards the big cities, deforestation and industrialization. All these factors are
increasing the temperature on earth. This increase in temperature is called global
warming. It is estimated that if global warming continues then the ice caps and
glaciers will melt and will bring floods.

Effects:
i. Rising of the Sea Levels and Floods
ii. Melting of Glaciers
iii. Heat Waves and Severe Precipitation
iv. Killer Storms
v. Drought
vi. Species becoming Extinct
Acid Rain
Acid rain occurs when these gases react in the atmosphere with water, oxygen, and
other chemicals to form various acidic compounds. The result is a mild solution of
sulfuric acid and nitric acid.

Causes:
The burning of fossil fuels and discharges from industries are emitting sulphur dioxide
and nitrogen dioxide in the air. Both these gases when enter the atmosphere
combine there with water vapours and forms acid.
Water vapours
Nitrogen dioxide Nitric acid + Nitrous acid
Water vapours
Sulphur dioxide Sulphurous acid + Sulphuric acid

Effects:
i. Acid rain destroys life. Many fish species and other aquatic animals are dying
and are unable to reproduce under these conditions.
ii. It causes destruction of farms, lakes and forests.
iii. It kills very important decomposer and microorganisms.
iv. It can destroy the huge buildings such as Taj Mahal. It is being destroyed due
to “stone cancer” caused by acid rain.
v. Acid rains can washouts essential nutrients from such as calcium and
potassium.
vi. Plants get poisoned and deprived of nutrients become weak and vulnerable
to infection and insects attack.

Eutrophication
It is a process in which fresh water bodies enriched with nutrients which increases its
productivity and organic debris.

 Process of eutrophication:
It is a gradual process in which large amount of plant life develops and
eventually decays. But this natural process is highly speeded up by human
activities. Human excreta, phosphates from washing powder and nitrates and
phosphates from fertilizers are adding large quantities of mineral and organic
nutrients. Due to large amount of minerals algal production rate is increased
and turn the water green called algal bloom. As die dead alga are
decomposed by aerobic bacteria they decrease the concentration of
oxygen in the water. This depletion of oxygen causes the death of aquatic
animals. In this way the water develops unpleasant color and smell.
 Death Process
1. Nutrients load up i.e. phosphates, nitrogen, calcium
2. Algal blooms
3. No light
4. Oxygen deficiency due to lack of photosynthesis
5. Organism dead i.e. unpleasant smell and odour
6. Decomposition by aerobic bacteria
 Life that only left behinds = Anaerobic bacteria
 Agro Chemical Products
Fertilizers, insecticides and pesticides are agro chemical products. Nowadays these
chemicals are widely used to increase the quality and quantity of crops.
Insecticide kills INSECTS
Fungicide kills PARASITIC FUNGI
Herbicide kills WEED PLANTS
 Insecticides:
Insecticides are the chemicals used to kill those insects which cause the harm
to crops.
 Pesticides:
On the other hand pesticide is a chemical which destroys agricultural pests or
competitors. Pesticides are harmful substances as they remain in our food in
small quantity. Peeling apples and potatoes removes most of surface
pesticides but alter pesticides are not sure to be removed. The use and
quantity of pesticides must be approved by ministry of agriculture.
 Fertilizers:
These are the chemical substances used to add additional nutrient in soil to
increase fertility. These fertilizers increase the productivity of crops. Many of
these chemical elements leave ecosystem by being bleached from hand
and drained into rivers which can cause high level of pollution. Man moves
chemical elements and minerals into ecosystem from concentrated natural
deposits for use as inorganic fertilizers.

C. Describe Nitrogen cycle (ammonification, nitrification,

assimilation, depletion).

Nitrogen Cycle
7. Biogeochemical cycle
8. Chief Reservoir of Nitrogen = Atmosphere 78%
9. Most living things cannot use atmospheric N2 or its compounds ; they are
dependent on N2 in soil, so shortage of N2 is soil is limiting factor in plant growth
10. Process by which limited amount of nitrogen is circulated and re-circulated
throughout the world of living organisms is called nitrogen cycle.
11. Nitrogen is a key component of the bodies of living organisms. Nitrogen atoms
are found in all proteins and DNA
12. When fertilizers containing nitrogen and phosphorous are carried in runoff to
lakes and rivers, they can result in blooms of algae—this is called eutrophication.
13. Three principle stages:
1. AMMONIFICATION
a. Before ammonification, nitrogen fixation takes place
i. Done in 3 ways
 ATMOSPHERIC NITROGEN FIXATION
&
N2(g) ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Nitrogen oxides ⎯ Nitous/Nitric Acid

 BIOLOGICAL NITROGEN FIXATION

N2(g) ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Nitrates

 INDUSTRIAL NITROGEN FIXATION

N2(g) + 3H2(g) ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ 2NH3(g)

 b. Most of nitrogen in soil is result of decomposition of organic materials
c. This nitrogen is in complex form i.e. protein, nucleotides, amino and
nucleic acids
d. Decomposed into simple compounds by soil dwelling bacteria and
fungi
Complex nitrogenous compounds ⎯⎯⎯⎯⎯⎯⎯⎯⎯ NH3 + NH4+

2. NITRIFICATION
a. Several bacteria are able to oxidize ammonia or ammonium ions
called nitrification
b. It involves two steps
i. Oxidation to nitrites

NH4+ ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ NO2‾

ii. Oxidation to nitrates

NO2‾ ⎯⎯⎯⎯⎯⎯⎯⎯ NO3‾

3. ASSIMILATION
a. Ammonium can be directly taken by plants
b. Nitrate is the form in which most of nitrogen is moved from soil to roots
c. This process requires energy
d. Within plants

Nitrates ⎯ NH4+ ions ⎯ Carbon containing compounds ⎯ Amino acids

DENITRIFICATION

a. Nitrates in soil are lost due to soil erosion, fire, and water percolating
down through the soil.
b. Nitrates are also lost as result of activities of certain soil bacteria
because in absence of oxygen they break nitrates, releasing nitrogen
back to atmosphere and using oxygen for their own respirtation
D. Define and explain Energy Flow, Trophic Levels (producers,
consumers, decomposers), Productivity, Food chain, Food
web.

Trophic Levels
Ecosystem is made of main three components:
1. PRODUCERS
 Green photosynthetic plants
 Light capturing
 Autotrophic organisms i.e. they prepare their food (organic
compounds) themselves from simpler inorganic substances
2. CONSUMERS
 They are all animals i.e. herbivores, carnivores, omnivores
i. HERBIVORES
 The animals feeding on producers (green plants)
 They are primary consumers
ii. CARNIVORES
 The animals feeding on herbivores (animals) are primary
carnivores
 The animals feeding on primary carnivores are called
secondary carnivores and so no
 They are starting from secondary consumer to onward
iii. OMNIVORES
 Such animals which can feed on both plants and animals
are called omnivore e.g. humans
 Heterotrophic organisms i.e. obtain energy directky or indirectly from
producers as ready-made organic food
3. DECOMPOSERS
 They are mainly fungi and bacteria
 Obtain energy from dead and decaying plants and animals and
release chemical elements as ions i.e. nitrates, ammonia, phosphate,
potassium, calcium
Food Chain
 The process of eating and being eaten up in an ecosystem

GRASS ⎯ CATERPILLAR ⎯ BLUE BIRD ⎯ EAGLE

(Producer) (Herbivore) (Primary Carnivore) (Secondary Carnivore)
Primary Consumer Secondary Consumer Tertiary Consumer

Food Web
 The combination of many food
chains
 They are not as simple as described
i.e. complex
 They always begin with green plants
 Variety of food chains in the food
web is done to maintain the stability
of an ecosystem
Productivity
 Productivity is the rate at which energy is added to the bodies of a group of
organisms (such as primary producers) in the form of biomass.
i. Gross primary productivity is the overall rate of energy capture.
ii. Net primary productivity is lower, adjusted for energy used by
organisms in respiration/metabolism.
respiration/metab It is called plant biomass
biomass.

Energy Flow
 Total energy trapped by producers in ecosystem = 1%
 99& of solar energy is used in evaporation, heating and lost to outer space
 Energy as bioproduct of respiration = 80 to 90%
 Short food chains are more efficient
effici than long food chains

 10% of energy of one trophic level is transferred to next trophic level

%
SUN ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ PRODUCERS ⎯ CONSUMERS ⎯ DECOMPOSER
100% energy 10% energy 1% energy
 TEST YOUR SELF

Q.1 Which one of the following is Q.7 The distinct levels or links of food
depleting and causing thinning of chain are called
ozone? A) Trophic level
A) Chlorine B) Food web
B) Bromine C) Energy pyramid
C) Chlorofluorocarbon D) Food chain
D) Carbon
Q.8 A relationship between two or
Q.2 The typical environment of a more organisms of different species
particular organism population in which all partners get benefit is
community is called called
A) Niche A) Symbiosis
B) Ecosystem B) Parasitism
C) Habitat C) Commensalism
D) Biosphere D) Predation

Q.3 Excessive enrichment of water with Q.9 Bacteria and fungi are examples of
nutrients by human activity by A) Producers
which large amount of living C) Consumers
organic matter grows is called B) Decomposers
A) Archeotrophication D) Denvers
B) Eutrophication
C) Enrichment Q.10 The cause of acid rain is
D) Low Trophication A) Oxides of carbon
B) Oxides of nitrogen and Sulphur
Q.4 In an ecosystem,
cosystem, mycorrhizae is an C) Oxides of Sulphur
example of D) Oxides of nitrogen
A) Symbiosis
B) Predation Q.11 In an ecosystem mycorrhizae are
C) Commensalism an example of:
D) Parasitism A) Predation
B) Symbiosis
Q.5 Successive stages of eating and C) Mutualism
being eaten by which recycling of D) Parasitism
materials and flow of energy takes
place is called Q.12 As a result of destruction of ozone
A) Food Chain layer there is significant increase
B) Food Web in:
C) Trophic Level A) Ultra-violet radiations
adiations
D) Food Link B) Greenhouse gases
C) Nitrogen oxide
Q.6 What is the niche of an organism in D) Sulphur oxide
an ecosystem?
A) Role played by many organisms Q.13 Higher rate of a biological activity
in an ecosystem in a nutrient rich pond water is
B) Role played by a dead called:
organism in an ecosystem A) Water pollution
C) Role played by community of B) Air pollution
microorganisms in an ecosystem C) Eutrophication
D) Role played by an organism in D) Industrial effects
its ecosystem
Q.14 Living part of ecosystem is: Q.20 The relationship in which one
A) Lithosphere organism gets benefit and the
B) Hydrosphere other is not affected is called
C) Community A) Mutualism
D) Biosphere B) Commensalism
C) Predation
Q.15 A living association between two D) Parasitism
living organisms of different species
which is beneficial to both the Q.21 Ozone is a layer of atmosphere
partners is called: extending from _______ km above
A) Commensalism earth and absorbs ultraviolent
C) Mutualism radiations.
B) Parasitism A) 10-50
D) Predation B) 50-60
C) 5-30
Q.16 Individual successions are known D) 10-80
as
A) Primary successions Q.22 Light rays from the sun are
B) Secondary successions absorbed by CO2 and re-radiate
C) Seres as ________ radiations.
D) Xeroses A) Ultraviolent
B) Indigo
Q.17 Which one of the following is the C) Infra-Red
ultimate distributional unit within D) Green
which a species is restrained by the
limitations of its physical structure Q.23 The gases which are produced by
and physiology? burning of fossils fuels and are
A) Niche responsible for acid rain are:
B) Biome A) CFCs
C) Ecosystem B) CO2 and CO
D) Habitat C) HCl and Oxides of Nitrogen
D) SO2 and Oxides of Nitrogen
Q.18 All herbivores belong to which
trophic level in the food chain? Q.24 During successions, the first
A) T1 organisms that develop on bare
B) T2 rock are:
C) T3 A) Lichens
D) T4 C) Moss
B) Shrubs
Q.19 How many food chains are present D) Herbs
in following food web?
Q.25 Trophic level of a herbivore in
Fox given food-web is:

Grass Snake Dog Owl Dog Fox

Frog
Beetle Spider
Rat Rabbit Bettle
Caterpillar Slug Wood Boring Bettle Wood Louse

Grass
Leaves Wood Bark
A) 1
A) 5 B) 3
B) 3 C) 4
C) 6 D) 2
D) 4
Q.26 The organisms of third trophic level Q.29 The change from bare rock or
are: open area is rapid, especially in
A) Primary consumer the initial stages and follows a
B) Primary producer series of recognizable and hence
C) Tertiary consumer predictable stages. This process is
D) Secondary consumer called:
A) Pioneers
Q.27 The ultimate source of energy in an B) Xerosere
ecosystem is: C) Succession
A) Photosynthesis D) Secondary succession
B) Sun
C) Plants
D) Water Q.30 The decline in the thickness of
ozone layer is caused by:
Q.28 All the food chains and food webs A) Increasing level of NOx
begin with: B) Decreasing level of O2
A) Detritus C) Decreasing level of CFCs
B) Herbivores D) Increasing level of CFCs
C) Green plants
D) Omnivores

Q.1 C Q.11 B Q.21 A

Q.2 C Q.12 A Q.22 C
Q.3 B Q.13 C Q.23 D
Q.4 A Q.14 D Q.24 A
Q.5 A Q.15 C Q.25 D
Q.6 D Q.16 C Q.26 D
Q.7 A Q.17 A Q.27
B
Q.8 A Q.18 B Q.28 C
Q.9 B Q.19 D Q.29 C
Q.10 B Q.20 B Q.30 D
9. Evolution
A. Compare the theory of Darwin and Lamarck.

Origin of life
Prokaryotes Evolution = 3.5 Billion year ago
Eukaryotes Evolution = 1.5 Billion year ago

1. HYPOTHESIS I – VENT HYPOTHESIS

a. Hot water springs underground
b. Archeabacteria supports this vent hypothesis – tolerate up to 120 °C

2. HYPOTHESIS III – MEMBRANE INVAGINATION HYPOTHESIS

3. HYPOTHESIS II – ENDOSYMBIONT HYPOTHESIS

a. Proposed by Lynn Margulis

Jean Baptiste Lamarck’s Theory

1. Published in 1809 (the year Darwin born)
2. Main points of the theory
a. Use and misuse of organs
Parts of body which are used extensively to cope with environment
become larger and stronger while others that are not used deteriorate.
b. Inheritance of acquired characteristics
Modifications that organism acquires during its lifetime can be passed
along to its offspring e.g. long neck of giraffe
Charles Darwin’s Theory
1. 1831 – Start journey from UK on Voyage of Beagle
a. Observe and collected thousand of specimens of floura and faua
b. Mainly observed floras and faunas of Galapagos Islands where he
collected 13 types of finches
2. 1836 – End of journey
3. 1844 – Essay ‘Origin of Species” published
4. 1858 – Wallace send papers
5. 1859 – Book of Darwin
6. CONCLUSION
New species would arise from ancestral from by gradual accumulation of
adaptations to different environments, separated from original habitat by
geographical barriers. Over many generations, the two populations could
become dissimilar enough to be designated as separate species.
7. MAIN POINTS OF THEORY
a. Descent with Modification
Life history is like tree with multiple branching and re-branching from
common truck all the way to the tips of living twigs, symbolic of the
current diversity of organisms.

b. Natural Selection and Adaptation

Overproduction > Struggle for existence > Survival of Fittest (Natural
Selection) > Evolution
8. NEO-DARWINISM
a. 1940
b. Supporting Darwin theory with other branches of science
i. Paleontology
ii. Taxonomy
iii. Biogeography
iv. Population genetics

LAMARCKISM DARWINISM
1. This theory states that there is an 1. This theory does not believe in the
internal vital force in all organisms. internal vital force.
2. It considers that new needs or desires 2. It contends that needs and/ or desires
produce new structures and change do not form part of Darwin’s natural
habits of the organism. selection theory.
3. According to this theory if an organ is 3. An organ can develop further or
constantly used it would be better degenerate only due to continuous
developed whereas disuse of organ variations.
results in its degeneration.
4. It does not consider struggle for 4. Struggle for existence is very important
existence. in this theory.
5. All the acquired characters are 5. Only useful variations are transferred to
inherited to the next generation. the next generation.
6. Lamarckism does not believe in survival 6. Darwin’s natural selection theory is
of the fittest. based on survival of the fittest.
B. Discuss evidences of evolution from Paleontology,
Comparative anatomy, Molecular biology and Biogeography.

Biogeography
1. Geographical distribution of species
2. Firstly suggested Darwin regarding evolution
3. EXAMPLES: Contemporary armadillos are modified descendants of earlier
species that occupied America and neighboring areas and the fossil record
conforms that such ancestors existed
Paleontology
1. Study of fossils
2. Forms of Fossils
a. Imprints
b. Cast/Mold
c. Body parts preservation in sedimentary rocks, gums, resins, ice
3. Fossils Ascending Sequence

A. Archeabacteria B. Cyanobacteria C. Eubacteria D. Eukaryotes

4. Vertebrates Sequence

Cotylosaurs D. Mammals
A. Fishes B. Amphibians C. Reptiles
Archaeopteryx E. Birds

Comparative Anatomy
1. Compares and contrasts anatomy of different species
2. HOMOLOGY: Similarity in characteristics resulting from common ancestry

HOMOLOGOUS ORGANS ANALOGOUS ORGANS VESTIGIAL ORGANS

Oldest, homologous and
Same structures Different structures
rudimentary structures
Functional in ancestors
Different functions Same functions
but now non-functional
Diveregent Evolution Convergent Evolution -
Examples: Examples: Examples:
 Forelimbs of bat, frog,  Wings of bat, birds and  Skeleton of whales and
fish and humans insects snakes have vestiges of
pelvis and leg bones of
walking ancestors
 Vermiform appendix in
carnivores
 Ear muscles in man
 Comparative Embryology
1. Compares and contrasts embryos of different species at different stages
2. Gives recap of the past explaining simplicity of organisms
3. EXAMPLES:
The embryo of fishes, frogs, snakes, birds, humans and all other vertebrae are
more apparent than different. As Gill pouches on the side of their throats.
 Fishes = GiIl pouches into gills
 Terrestrial vertebra = Gill pouches into other structures
 Human = Gill pouches into Eustachian tube that connects middle ear
with throat

Molecular Biology
1. Study of structure and function of the macromolecules essential to life.
2. DNA, proteins ,genes and gene products
3. EXAMPLES:
 Common genetic code = All life is related = unity of life = Diversity of life
 Proteins in common between human and bacteria
CYTOCHROME C, A RESPIRATORY PROTEIN (in all aerobic species)

C. Explain Hardy-Weinberg Theorem and factors affecting gene /

allele frequency

Hardy-Weinberg Theorem
1. Discovered in 1908 by Hardy and Weinberg independently
2. STATEMENT
“The frequencies of alleles and genotypes in a population gene pool remain
constant over the generations unless acted upon by agents other than sexual
reproduction.”
3. No effect of gene shuffling on this theorem by
a. Meiosis
b. Random fertilization
4. HARDY WEINBERG’S EQUATION
p² + 2pq + q² = 1
p = frequency of dominant allele (A)
q = frequency of recessive allele (a)
In other words
p is equal to all of the alleles in individuals who are homozygous dominant
(AA) and half of the alleles in people who are heterozygous (Aa) for this
trait in a population. In mathematical terms, this is
p = AA + ½Aa
Likewise, q equals all of the alleles in individuals who are homozygous
recessive (aa) and the other half of the alleles in people who are
heterozygous (Aa).
q = aa + ½Aa
Because there are only two alleles in this case, the frequency of one plus the
frequency of the other must equal 100%, which is to say
p+q=1
Since this is logically true, then the following must also be correct:
p=1–q or q=1–p
Here
 (p + q)² = 1 or p² + 2pq + q² = 1
p² = predicted frequency of homozygous dominant (AA)
2pq = predicted frequency of heterozygous (Aa)
q² = predicted frequency of homozygous recessive (aa)

Genotype Frequency:
Number of genotypes in population
Genotype frequency =
Total number of genotypes in population

Allele Frequency:

Number of copies of allele in population

Allele frequency =
Total number of gene copies in population

Genotype and Allele relation:

1 Genotype = 2 Alleles

Factors affecting gene/allele frequency

FACTOR DESCRIPTION
 Spontaneous change in any part of DNA
 Ultimate source of all changes
Mutation
 Individual mutations occur very rarely i.e. they do not effect allele
frequency much
 Movement of organism from one place to another in search of
food, shelter etc
Migration
 Very potent agent of change
 Emigration and immigration cause much disturbance in gene pool
 Change in frequency of alleles at a locus that occurs by chance
 Occur more strongly in small population i.e. limiting such genes in
Genetic Drift
that population which is fail to reproduce
 Such genes are lost from small populations
  Individuals with certain genotypes sometimesometimes mate with one
another more commonly than would be expected on random
Non-Random basis.
Mating  Inbreeding is common form
 Do not alter allele frequency but lessens the proportion of
heterozygote individuals
indi
 Some individuals leave behind more progeny than others, ansd
the rate at which they do so is affected by their inherited
characteristics. This is called selection.
ARTIFICIAL SELECTION NATURAL SELECTION
 Breeders select for desired  Environment select for the
traits traits
Selection
 Little resemblance to wild  Amplify or diminish
ancestors inheritable traits
 Achieved in short period of  Achieved in vast span of
time time
 E.g. Mule  E.g. Antibiotic resistance in
bacteria

TEST YOUR SELF

Q.1 The comparative embryology of all Q.4 Which one of the fo following is
vertebrates shows development of considered as strong evidence of
A) Hairs evolution?
B) Gill pouches A) Embryology Record
C) Scales B) Molecular Record
D) Fins C) Biochemical Record
D) Fossil Record
Q.2 The structures which are reduced
during the course of evolution and Q.5 Structures found in different species
have no apparent function are which are believed to have a
called: common evolutionary origin are
A) Regenerated organs
rgans called:
B) Vestigial organs A) Homologous
C) Salutatory organs B) Analogous
D) Useless organs C) Vestigial
D) Fossilized
Q.3 From evolutionary point of view,
which respiratory protein is
common in many organisms?
A) Cytochrome a
Q.1 B Q.3 C Q.5 A
B) Cytochrome b Q.2 B Q.4 D
C) Cytochrome c
D) Cytochrome d
10. Genetics (Part – I)
A. Explain the terms: Gene, locus, allele, dominant, recessive, co-
dominant, linkage, F1 and F2, phenotype, genotype,
homozygous, heterozygous, mutation, epistasis, multiple allele,
Rh factor, dominance relations, polygenic inheritance.

Genes:
 Units of inheritance
 Physically, a sequence of DNA bases that specify the order of amino acids in
an entire protein or, in some cases, a portion of a protein.
 At specific locations, or loci, on a chromosome
 Responsible for the hereditary traits in plants and animals
 TYPES:
 ALLELIC GENE: Genes occurring in form of pairs
 NON-ALLELIC GENES: Genes occurring in unpaired forms e.g. haemophilia

Gene pool:
 All the genes/alleles found in breeding population at given time collectively
 Total genetic information

Locus:
 Location of allelic genes on chromosome

Allele:
 Alternate forms/varieties/partners of a gene
 Alleles for same trait occupy same locus or position on homologous chromosomes

GENE ALLELE
Genes are something we inherit from our Alleles determine how they are expressed
parents in an individual.
There is no such pairing for genes Alleles occur in pairs
No such generalization can be assigned to A pair of alleles produces opposing
genes. phenotypes
Genes we inherit are same for all humans. How genes manifest themselves is actually
determined by alleles!
Dominant Allele:
 An allele that masks presence of a recessive allele in phenotype.
 Dominant alleles for a trait are usually expressed if genotype is
 HOMOZYGOUS DOMINANT
 HETEROZYGOUS

Recessive Allele:
 An allele that is masked in the phenotype by presence of a dominant allele.
 Recessive alleles are expressed in the phenotype when the genotype is
 HOMOZYGOUS RECESSIVE
Co-dominant Allele:
 Different alleles of a gene that are both expressed in phenotype
independently when genotype is
 HETEROZYGOUS
DOMINANT RECESSIVE
GENE/FACTOR/TRAIT/ALLELE GENE/FACTOR/TRAIT/ALLELE
Able to express itself even in presence of its Unable to express its effect in presence of
recessive allele dominant allele
Does not require another similar allele to Produces its phenotypic effect only in the
produce its effect on the phenotype presence of a similar allele
Can form complete polypeptide or Can form an incomplete or defective
enzyme for expressing its effects polypeptide or enzyme so that the
expression consists of absence of the
effect of dominant allele
Linkage:
 Phenomenon of certain genes staying together during inheritance through
generations without any change or separation due to their being present on
the same chromosome.
 Man has 23 linkage groups
 Genes for haemophilia, gout, colour blindness = X-chromosome
 Genes for sickle cell anemia, leukemia, albinism = Chromosome 11
 Linked genes who loci are close do not assort independently during meiosis.
 It minimizes
 Genetic recombination
 Variations among offspring
First Filial Generation F1:
 First offspring (or filial) generation
 The next and subsequent generations are referred to as F2, F3 onward
Second Filial Generation F2:
 Second offspring (or filial) generation
 First offspring (or filial) generation will be parental generation for F2
Phenotype:
 Appearance of trait
 Physical or biochemical characteristics of an organism which are determined
by their genetic make-up or environment.
Genotype:
 Set of alleles carried by an organism at a particular locus
 Genetic makeup of an individual
 Organism's entire genetic makeup
GENOTYPE PHENOTYPE
Gene complement of an individual External manifestation of gene product
brought to expression
Remains the same throughout the life of an May change with time, e.g., infant,
individual. adolescent, young and old.
Cannot be studied directly. Can be known through direct observation.
Not influenced by phenotype Genotype establishes boundaries within,
which phenotype can be expressed.
Similar genotypes will produce similar Individuals with similar phenotypes may not
phenotypes. belong to same genotype.
Not influenced by environment Can change with change in environment
Homozygous:
 Individual having same alleles at same locus on both members of a pair of
homologous chromosomes are called homozygotes
 Genotype consists of two identical alleles of a gene for a particular trait. An
individual may be
 Homozygous dominant (AA)
 Homozygous recessive (aa)

Heterozygous:
 Individual having different alleles at same locus on both members of a pair of
homologous chromosomes are called heterozygotes
 Genotype consists of two different alleles of a gene for a particular trait (Aa).

HOMOZYGOUS HETEROZYGOUS
Pure for a trait and breeds true Seldom pure and produces offspring with
different genotypes
Both alleles of a character are similar Dissimilar alleles
Either dominant or recessive alleles at one Both dominant and recessive alleles at one
time time
Produces one type of gametes Produces two type of gametes

Mutation:
 Change in the base pair sequence of DNA or RNA
 Mutations in germ cells = can be inherited
 Mutations in somatic cells = cannot be inherited

Epistasis:
 Interaction of two gene pairs located on different loci
 Expression of ABO Blood type antigens IA and IB gene = gene H.
 ABO locus = chromosome 9
 H-locus = chromosome 11
 H-gene produces an enzyme that inserts a sugar on to a precursor
glycoprotein on RBC surface while h-gene cannot attach it.
Antigen + H gene = sugar attached
Antigen + h gene = no sugar attached

IA antigen + H gene = sugar attached = A blood group

IB antigen + H gene = sugar attached = B blood group
IA IB antigen + H gene = sugar attached = AB blood group
No antigen + H gene = no sugar attached = O blood group
Multiple Allele:
 Three or more kinds of gene which occupy the same locus are referred to as
multiple alleles.
 EXAMPLE:
 ABO Blood group System in man

Rh-Factor:
 Rhesus (Rh) factor is an inherited protein found on the surface of red blood
cells.
 If your blood has the protein (DD, Dd),, you're Rh positive.
 If your blood lacks the protein (dd),, you're Rh negative.
 Enclosed by 3 genes C, D and E
 Alleles of D occupy on same locus – more important
 D is completely dominant over d
 Alleles of C and E alternatively on other locus

Dominance Relations:
Relations
 Physiological effect of an allele over its partner allele
 4 relations
 COMPLETE DOMINANCE:
When one allele is completely dominant over the other.
Dominant = Expressed dependently
Recessive = Masked dependently
Phenotype = Same in Dominant Heterozygote & Homozygote
Genotype = Different in Heterozygote & Homozygote

 INCOMPLETE DOMINANCE:
When phenotype
phenotype of heterozygote is immediate between phenotypes of
the two homozygotes.
homozygotes
Dominant = Expressed dependently
 Recessive = Expressed dependently
Phenotype = Different in Heterozygote & Homozygote
Genotype = Different in Heterozygote Homozygote
Example: 4 o’clock
o’c flower

 CO-DOMINANCE:
DOMINANCE:
When phenotype of heterozygote is immediate between phenotypes of
the two homozygotes.
homozygotes
Dominant = Expressed independently
Recessive = Expressed independently
Phenotype = Different in Heterozygote & Homozygote
Genotype = Different in Heterozygote Homozygote
Example: MN Blood Group System (on basis of specific antigens in RBC)

 OVER DOMINANCE:
Over-dominant
dominant heterozygote exceeds in quantity the phenotypic
expression of both homozygotes.
Dominant = Expressed at same time
Recessive = Expressed at same time
Phenotype = Different in Heterozygote & Homozygote
Genotype = Different in Heterozygote Homozygote
Example: Fruit fly Drosophila, the heterozygote (w+/w) has more
quantity of fluorescent pigments in eyes than wild (w+/w+) or white eye
(w/w) homozygotes.
 Polygenic Inheritance:
 Polygenic inheritance occurs when one characteristic is controlled by two or
more genes. Often the genes are large in quantity but small in effect.
 Continuously varying trait
 Genes are called polygenes
 EXAMPLES
 Human height
 Human skin color
 Human eye color
 Human weight

B. Explain law of segregation and law of independent assortment

through Punnet square, solve problems related to monohybrid,
dihybrid crosses and testcross.

Punnet square:
 Can be used to predict genotypes (allele combinations) and phenotypes
(observable traits) of offspring from genetic crosses.

Monohybrid Cross:
 Mono-hybrid cross is when the offspring of homozygous parents that only differ
on a single trait are bred to come up with the second generation.

Dihybrid Cross:
 Di-hybrid cross is pretty similar to a monohybrid cross except that the parents of
the first generation differ in two traits.

MONOHYBRID CROSS DIHYBRID CROSS

Cross between two pure organisms in Cross between two pure organisms of a
order to study the inheritance of a single species in order to study the inheritance
pair of alleles. of two pairs of alleles.
Produces a phenotypic monohybrid ratio Produces a phenotypic di-hybrid ratio of
of 3 : 1 in F2 generation. 9 : 3 : 3 : 1 in F2 generation
Produces genotypic ratio of 1 : 2 : 1 in F2 Produces genotypic ratio of 1 : 2 : 1 : 2 : 4
: 2 : 1 : 2 in F2 generation

Test cross:
 Can be used to determine whether an organism with a dominant phenotype is
homozygous or heterozygous.

Dominant Phenotype x Recessive Phenotype

(Yellow-seeded plant) x (Green-seeded plant)
YY or Yy x yy
Mendel’s Pea Traits:
Traits
A. Law of segregation:
segregation
 Only
nly one of the two gene copies present in an organism is distribut
distributed to each
gamete (egg or sperm cell) that it makes, and the allocation of the gene
copies is random. When an egg and a sperm join in fertilization, they form a
new organism, whose genotype consists of the alleles contained in the
gametes.

B. Law
w of independent assortment:
assortment
 Alleles
lleles of two (or more) different genes get sorted into gametes independently
of one another. In other words, the allele a gamete receives for one gene
does not influence the allele received for another gene.
Probability:
 Chance of an event to
occur
 PRODUCT RULE:
For independent events
X and Y, probability (P)
( of
them both occurring:
P(X) . (P(Y)

 SUM RULE:
For mutually exclusive
events X and Y,
probability (P) that one
will occur:
P(X) + (P(Y)
 DO YOU KNOW BUDDY?

ABO Blood Group System is controlled by single polymorphic gene

BLOOD DONATION RULE:
“Antigen
Antigen of donor and antibodies of recipient must be different
different”
ANTIGEN ANTIBODY GENETICS GROUP DONATION
A B IAIA, IAi A A, AB
B A IBIB, IBi B B, AB
A, B None IAIB AB AB
None A, B ii O A, B, AB, O

C. Discuss gene linkage and sex linkage in human (haemophilia

and colour blindness).

Gene Linkage:
 “Phenomenon
Phenomenon of certain genes staying together during inheritance through
generations without any change or separation
separation due to their being present on the
same chromosome is called linkage”
 Man has 23 linkage groups
 Genes for haemophilia, gout, colour blindness = X-chromosome
 Genes for sickle cell anemia, leukemia, albinism = Chromosome 11
 Linked genes who loci are
are close do not assort independently during meiosis.
 It minimizes
 Genetic recombination
 Variations among offspring
Sex Linkage:
 No. of chromosomes in humans = 46 = 23 homologous pairs
 Autosomal = 44 = 22 pairs
 They are common in both sexes
 Sexual = 2 = 1 pair
p
 Different in both male and female
FEMALE (She) MALE (He)
2 similar chromosomes 2 different chromosomes
XX XY

Homogametic Heterogametic

 Y is much short chromosome.

 SRY is the male determining gene located at tip of short arm of Y
Y-
chromosome.
 SRY
RY stands for “SEX
“ determining REGIONS of Y”
 This gene is present from 6th week of pregnancy
 CHROMO
TRAIT EXAMPLE INHERITANCE OCCURRENCE CROSS
SOME
M F
 Albinism
Equal from
 Sickle cell 1st to Both male
Autosomal both
anemia 22nd pair and female
parents
 Leukemia

M F
 Hypo- Not equal
X-linked Females
phosphatemic X from both
dominant mostly
rickets parents

 Testicular M F
feminization
Not equal
X-linked syndrome Males
X from both
recessive  Haemophilia mostly
parents
 Colour
blindness
M F

Father to
Y-linked  Maleness Y Male only
son

M F
Equal from
Pseudo-  Bobbed gene Both male
X or Y both
autosomal in drosophila and female
parents

Haemophilia:
 X-linked recessive / autosomal disease
 Royal disease
 Bleeding disease i.e. Blood fails to clot properly after an injury
 Reduction or malfunction or complete absence of blood clotting factors
 Types (3 types)
FEATURE HAEMOPHILIA A HAEMOPHILIA B HAEMOPHILIA C
Trait X-linked recessive X-linked recessive Autosomal (4)
Percentage 80% 20% less than 1%
Clotting factor VIII IX XI
Non-allelic Males only Males only -
Allelic Females only Females only Both male & female
Effect MOST COMMON IN MALES EQUAL

XHXH XHXh XhXh XHY XhY

Homozygous Heterozygous Homozygous Hemizygous Hemizygous
DOMINANT (carrier) RECESSIVE
Colour Blindness:
 X-linked recessive
 True colour blindness = MONOCHROMACY
FEATURE RED OPSINS GREEN OPSINS BLUE OPSINS
Trait X-linked recessive X-linked recessive Autosomal (7)
Non-allelic Males only Males only -
Allelic Females only Females only Both male & female
Effect MOST COMMON IN MALES EQUAL

XCXC XCXc XcXc XCY XcY

Homozygous Heterozygous Homozygous Hemizygous Hemizygous
DOMINANT (carrier) RECESSIVE

Vision

Day Night

Cone Cells Rod Cells

Red Opsins Green Opsins Blue Opsins

X-chromosome X-chromosome Autosome No 7

Colour Vision

Normal Partial Blind Complete Blind

Trichromacy Anomaly Dichromate Monochromate

Protonomalous Deuteonomalous Tritanomalous Can see 2 Can see 1

colours only colour only
Red Blind Green Blind Blue Blind
E.g. Blue Cone
monochromacy
Testicular feminization syndrome (tsf):
 Rare X-linked
linked recessive
 Androgen insenditivity syndrome
 Testosterone is produced but has no effect on them
 Genotypically MALE XY
 Phenotypically FEMALE XX
 They have breast, female ginitilia, a blind vagina but no uterus

SRY

tfm TFM X Y
no receptors recep
receptors testosterone

FEMALE MALE

Hypophosphatemic rickets:
rickets
 X-linked dominant
 True hereditary disease
 Genetic communication failure at molecular level
 More common in females than males
 Non-allelic
allelic in males but allelic in females

XDXD XDXd XdXd XDY XdY

Homozygous Heterozygous Homozygous Hemizygous Hemizygous
DOMINANT (carrier) RECESSIVE

Maleness:
 Y-linked
 Transfer from male to son only
FEATURE RED OPSINS GREEN OPSINS BLUE OPSINS
Trait X-linked
linked recessive X-linked recessive Autosomal (7)
Non-allelic Males only Males only -
Allelic Females only Females only Both male & female
Effect MOST COMMON IN MALES EQUAL

XX XYSRY
Homozygous Heterozygous
Diabetes:
INSULIN DEPENDENT (IDDM) NON-INSULIN
INSULIN DEPENDENT (NIDDM)
Type – I Type – II
Before 40 years After 40 years
Autoimmune disorder Genetic or due to obobesity
No insulin production Insulin produced but no response
External insulin can work External insulin cannot work

 2-5%
5% of NIDDM is before age of 25 years is called MODY ((Maturity Onset
Diabetes of the Young).
oung).
 Diabetes Type – I and Blood pressure are examples of multi-factorial
factorial disease.

DO YOU KNOW BUDDY?

SEX
EX LIMITED TRAITS are those which are limited to one sex only but
are control by sex-linked
sex or autosomal genes or both e.g. milk
production in females and beard growth in males.
males But such such genes
can cross from parents to both daughters and sons.
SEX INFLUENCED TRAITS are those which occur in both males and
females but more common in one sex. It is controlled by dominant allele
in one sex while recessive in the opposite sex. It may be d
due to
hormonal differences in both sexes e.g. Pattern baldness. It is
autosomal dominant in males while autosomal recessive in females.
Heterozygous male will be bald but not heterozygous females
females.
Homozygous recessive females will be bald.
D. Discuss hypothesis about DNA Replication, Meselson and Stahl
experiment and mechanism of replication.

DNA Replication Hypotheses:

FEATURE HYPOTHESIS 1 HYPOTHESIS 2 HYPOTHESIS 3
Name Conservative Semi-conservative Dispersive
Proposed by - Watson and Crick Max Delbrück
“The entire DNA
molecule acted as a
“Breaks the DNA
template for the “Two strands of a
backbone every 10
synthesis of an DNA molecule
nucleotides or so,
entirely new one. separate during
untwists the molecule,
Statement Histone proteins bind replication. Each
and attaches the old
to the DNA, revolving strand then acts as a
strand to the end of
the strand and template for synthesis
the newly synthesized
exposing nucleotide of a new strand.”
one.”
bases for hydrogen
bonding.”
Unwinding of
Done Done Not done
2 strands
After One duplex old + All One old + One new Each duplex is mixture
replication duplex new strand in each duplex of old and new DNA

Meselson and Stahl Experiment:

 They used DNA of E. coli bacteria.
 They proved that DNA replication is done by semi-conservative way.
 PROCEDURE:
 They growth bacteria in medium containing heavy isotope of nitrogen
N-15
 When grown on medium containing heavy N-15 the bacteria took up
the nitrogen and used it to synthesize new biological molecules,
including DNA.
  Then they transfer bacteria from N-15
N to N-14
14 medium and collected
DNA at different intervals.
 They dissolved the different samples of collected DNA in cesium
chloride and spun it at very high speed in an ultra-centrifuge.
ultra centrifuge.
 Ultracentrifuge great gradient
gradient of CsCl i.e. density in the bottom and
help in separating the DNA at various densities.

OBSERVATION RESULT
GENERATION
N-15 Inter N-14 TOTAL

0 100% - - 1 Heavy duplex -

Dispersive and
1 - 100% - 2 Hybrid duplex
Semiconservative
2 Hybrid duplex
2 50% 50% Semiconservative
2 light duplex
2 Hybrid duplex
3 25% 75% Semiconservative
6 light duplex
2 Hybrid duplex
4 12% 88% Semiconservative
14 light duplex

DNA Replication Mechanism:

Mechanism
 Begins at one or more sites on DNA molecules where
where there are sequences of
nucleotides.
 ENZYMES
1. DNA HELICASE
 Opening of DNA at replication fork
2. TOPOISOMERASE
 Works
orks at the region ahead of the replication fork to prevent
supercoiling.
3. DNA POLYMERASES (5 in human, 3 in bacteria)
 Cannot initiate synthesis of new strand at its own but need
another enzyme

FEATURE DNA POLYMERASES I DNA POLYMERASES II DNA POLYMERASES III

Polymerizaion
Low Low High
Rate
Processivity Low Low High
3 to 5 and 5 to 3 3 to 5 3 to 5
Proof Reading
Exonulease activity Exonulease activity Exonulease activity
Primer
Best - -
Removal
Strand Lagging + Leading
Lagging strand No role
Synthesis strand
DNA repair Active Active -
10 times larger +
Size Small -
Complex + Dimer
Threads the DNA
through enzyme
Supporting role in True E.Coli
Function complex at rapid rate
DNA replication replicating enzyme
of 1000 nucleotides per
second

4. PRIMASE
 A sequence of about 10 RNA nucleotides complementary to
parental DNA template
5. DNA LIGASE
 Enzyme for attachment of leading to lagging strand

 STRANDS

1. LEADING STRAND
 Strand,
trand, which runs 5' to 3' towards the replication fork,
 Easily made
 Made
ade continuously, because the DNA polymerase is moving in
the same direction as the replication fork
2. LAGGING STRAND
 Strand,
trand, which runs 5' to 3' away from the fork
 Not easily made
  Made
ade in fragments because, as the fork moves forward, the DNA
polymerase (which is moving away from the fork) must come off
and reattach on the newly exposed DNA.
 These small fragments are called Okazaki fragments
a) About 100-200 nucleotidess long in eukaryotes
b) About 1000-2000
2000 nucleotides long in prokaryotes

 DNA replication in Bacteria

1. Helicase opens up the DNA at the replication fork.
2. Single-strand
strand binding proteins coat the DNA around the replication fork
to prevent rewinding of the DNA.
3. Topoisomerase
poisomerase works at the region ahead of the replication fork to
prevent supercoiling.
4. Primase synthesizes RNA primers complementary to the DNA strand.
5. DNA polymerase III extends the primers, adding on to the 3' end, to
make the bulk of the new DNA.
6. RNA primers
imers are removed and replaced with DNA by DNA polymerase II.
7. The gaps between DNA fragments are sealed by DNA ligase
ligase.

E. Explain mechanism of gene expression: Transcription and

Translation.

TRANSCRIPTION
 First
irst step in gene expression.
 Copying
opying a gene's DNA sequence to make an RNA molecule.
 Occurs in nucleus
 TEMPLATE/ANTISENSE STRAND:
STRAND One one of two strands of DNA transcribed
 CODING/SENSESENSE STRAND:
STRAND One one of two strands of DNA not transcribed
 Main
ain enzyme involved = RNA polymerase
 Prokaryotes: 1 type (rRNA, mRNA, tRNA)
 Eukaryotes: 3 types i.e. I(rRNA), II(mRNA), III(tRNA)
 It uses a single-stranded
single stranded DNA template to synthesize a complementary
strand of RNA in the 5' to 3' direction, adding each new nucleotide to
the 3' end of the strand.

 PROMOTER: RNA polymerase

polymerase binding site where transcription started
 Prokaryotes = 2 binding sites
1. TTGACA = –35 sequence
2. TATAAT = –10 sequence
  Eukaryotes = 2 binding sites
1. TTGACA = –75 sequence
2. TATAAT = –25 sequence
 TRANSCRIPTION BUBBLE: Before transcription can take place, the DNA double
helix must unwind near the gene that is getting transcribed. The region of
opened-upup DNA is called a transcription bubble.
 Transcription has three stages
 Initiation
 Elongation
 Termination

A. Initiation
1. RNA polymerase
binds to a sequence
of DNA called
the promoter,, found
near the beginning
of a gene.
2. Once bound, RNA
polymerase
separates the DNA
strands, providing
the single-stranded
template needed
for transcription. The
region called
transcription bubble..

B. Elongation
1. One strand of DNA, the template strand,, acts as a template for RNA
polymerase.
2. As it "reads" this template one base at a time, the polymerase builds an RNA
molecule out of complementary nucleotides, making a chain that grows from
5' to 3'.
3. The RNA transcript carries the same
sa information as the non-template
template ((coding)
strand of DNA, but it contains the base uracil (U) instead of t hymine (T).
C. Termination
1. Sequences called terminators signal that the RNA transcript is complete.
2. Once they are transcribed, they cause the transcript
transcript to be released from the
RNA polymerase. An example of a termination mechanism involving
formation of a hairpin in the RNA is shown below.

After transcription
 Prokaryotes = Directly release of mRNA into cytoplasm
 Eukaryotes = Release of mRNA fromfrom Nucleus to Ribosomes to Cytoplasm
 Journey aided in several way to protect from nucleases and
phosphatases
 Cap of 7 methyl GTP linked to 5’ to 5’ with first nucleotide
 Tail of poly A tail linked to 3’ end of mRNA

TRANSCRIPTION
 Second step in gene expression.
expres
 mRNA is "decoded" to build a protein containing
contain specific series of amino acids.
 Occurs in ribosomes

 AMINOACYL tRNA SYNTHETASE is activating enzyme fir attachment of specific

amino acids (out of all 20) to particular tRNA molecules.
 Translation hass three stages
 Initiation
 Elongation
 Termination
A. Initiation
1. Ribosome assembles around the mRNA to be read
2. tRNA carrying the amino acid methionine (N-formyl formyl methionine + Small
ribosome subunit unit = Initiation factor proteins
3. Initiation factor (proteins) position tRNA on ribosome at P site
4. P – site = Peptiydyl site = Peptide bond formation site
5. A – site = Aminoacyl site = Successive amino acid bearing tRNA binding site
6. E – site = Exit site = Empty tRNA exiting site
7. This is called initiation complex
B. Elongation
1. tRNA is binded by Large ribosome subunit + Anticodon = Elongation factor
proteins
2. Elongation factor help in binding tRNA to exposed mRNA at A – site
3. Chemical reaction between adjacent amino acids take place
4. Initial methionine release from tRNA and
and attached with help of larger ribosome
subunit to second amino acid.
5. Movement of this ribosome over three more nucleotides along mRNA take
place in 5 to 3 direction
6. More elongation factors release, initial tRNA translocated to E site and ejects
from ribosome
ome while it repositions the growing polypeptide chain to A – site
7. Same process is repeated
 C. Termination
1. Chain elongation continue in this fashion until chain terminating non-sense
codon (UAG, UAA, or UGA) enters the ribosome due to release factors,
triggering a series of events that separate the chain from its tRNA and allow it
to drift out of the ribosome.

After translation
After termination, the polypeptide may still need to fold into the right 3D shape,
undergo processing (such as the removal of amino acids), get shipped to the right
place in the cell, or combine with other polypeptides before it can do its job as a
functional protein.

F. Describe Genetic code and its properties.

Genetic Code:
 “Combination of 3 nucleotides which specify a particular amino acid”
 2-nucleotide codon is not acceptable as for 4 DNA nucleotides only 42 or 16
different pairs will be formed which are not enough to code for 20 different
amino acids.
42 = 16 
43 = 64 
 Tested for any errors by making artificial mRNAs and triplet codons by
 Crick
 Marshall Nirenberg
 Philip Leader
 Har Gobind Khorana
 Total Codon = 64
 Non-sense codons = Stop codons = 3 (UAA, UAG, UGA) – present at end of genes
 Inititation Codon = AUG (encloses methionine)
 It is universal i.e. almost same in all organisms
 AGA species arginine in bacteria, humans and all organisms
 It is not universal i.e. not same in few cases

CODON NORMALLY MITOCHONDRIAL DNA

UGA Stop Codon Reads tryptophan
AUA Isolecine Methionine
AGA Reads Arginine Termination of protein synthesis
AGG Reads Arginine Termination of protein synthesis

G. Explain sex chromosomes and discuss different systems of sex

determination (XO-XX, XY-XX, ZZ-ZW)

Sex determination patterns:

 ZZ-ZW is firstly discovered by J-Seiler in 1914 in moths.
 FEATURE XY--XX XO-XX ZZ-ZW
Heterogametic –XY Heterogametic –XO
 X-chromosome
chromosome  X-chromosome Homogametic – ZZ
Male
 Y-chromosome
chromosome  Nullogamete
Heterogametic –ZW
Homogametic – XX Homogametic – XX  ZZ-chromosome
Female
 WW-chromosome
 Birds
 Drosophila  Grasshopper
Examples  Butterflies
 Humans etc  Protenor bug etc
 Moths

P1 XX XY XX XO ZZ ZW

X ½X ½Y X ½X ½O Z ½Z ½W
Egg Sperms Egg Sperms Sperms Egg

Gametes

F1
XX XY XX XO ZZ ZW

Offspring ratio 1 : 1 1 : 1 1 : 1

DO YOU KNOW BUDDY?

Q.1 The sex of individuals of next Q.2 Which of the following will be
generation always depends on hemophilic?
onee of the parents who is A) XHXh
A) Heterogametic B) XHXH
B) Homogametic C) XhY
C) Isogametic D) XHY
D) Isomorphic
Q.3 Which of the following is an Q.10 In men, sex determination depends
example of X-linked recessive trait upon the nature of
in humans? A) Heterogametic male
A) Hypophospatemic Rickets B) Homogametic female
B) Colour Blindness C) Heterogametic female
C) Baldness D) Homogametic male
D) Beard Growth
Q.11 A character determined by three
Q.4 Which trait in human in an example alleles is:
of multiple alleles? A) Human skin colour
A) Eye Colour B) Human blood group
B) Skin Colour C) Human eye colour
C) ABO-Blood Group D) Human Rh factor
D) Rh-Blood Group
Q.12 When a gene suppresses the effect
of another gene at another locus
Q.5 When a gene pair at one locus the phenomenon is termed as:
interacts with another gene at A) Over dominance
another locus, the interaction is B) Pleiotropy
called C) Epistasis
A) Dominance D) Co-dominance
B) Multiple Alleles
C) Pleiotropy Q.13 Phenylketonuria is an example of:
D) Epistasis A) Polyploidy
B) Transmutation
Q.6 When the presence of a gene at C) Inversion
one locus suppresses the effect of D) Point mutation
a gene at another locus, the
phenomenon is called Q.14 A situation in which one gene
A) Hypostasis affects two or more unrelated
B) Pleiotropy characters is called:
C) Epistasis A) Epistasis
D) Epitropy B) Pleiotropy
C) Dominance relation
Q.7 The gene for ABO-blood group D) Polygenes
systems in humans is represented
by symbol: Q.15 The mutation which causes change
A) X in the sequence of DNA is called:
B) I A) Point mutation
C) Y B) Chromosomal mutation
D) O C) Deletion
D) Inversion
Q.8 When a single gene affects two or
more traits, the phenomenon is Q.16 When a gene expresses the effects
called of a gene at another focus, this is
A) Epistasis known as
B) Pleiotropy A) Epistasis
C) Dominance B) Co-dominance
D) Over dominance C) Complete dominance
D) Mutation
Q.9 Which one of the following is X-
linked trait? Q.17 In male the sex determining gene
A) Male pattern baldness is
B) Diabetes mellitus A) XY
C) Haemophilia B) SRY
D) Erythroblastosis fietalis C) SYX
D) SXX
Q.18 A gene which affects two or more Q.26 One of the pyrimidine bases is
unrelated characteristics is called absent in DNA
A) Pleiotropic A) Uracil
B) Epistatic B) Thymine
C) Dominant C) Cytosine
D) Mutant D) Adenine

Q.19 Position of a gene within a DNA Q.27 Which of the following combination
molecule is of base pair is absent in DNA?
A) Locus A) A–T
B) Origin B) C–G
C) Amplicon C) A–U
D) Filial D) T–A

Q.20 Sickle cell anemia is a type of Q.28 Which of the following is purine:
A) Insertion A) Guanine
B) Transposition B) Cytosine
C) Deletion C) Thymine
D) Base Substitution D) Uracil

Q.21 X-linked recessive trait is: Q.29 If the genetic code is made up of
A) Hypophosphatemia three nucleotides, then total
B) Vitamin-D resistant rickets possible genetic codes will be
C) Haemophilia A) 4
D) Diabetes Mellitus B) 20
C) 64
Q.22 Human skin colour is a good D) 61
example of?
A) Sex-linked inheritance Q.30 Number of base pairs in one turn of
B) Polygenic inheritance DNA:
C) x-linked inheritance A) 10
D) y-linked inheritance B) 2
C) 34
Q.23 The total number of genes in a D) 54
population is called:
A) Gene pool
B) Allele pool
Q.1 A Q.11 B Q.21 C
C) Genome Q.2 C Q.12 C Q.22 B
D) Genomic library
Q.3 B Q.13 D Q.23 A
Q.24 Number of pairs of autosomes in
humans in: Q.4 C Q.14 B Q.24 D
A) 23
B) 24
Q.5 D Q.15 A Q.25 C
C) 21 Q.6 C Q.16 A Q.26 A
D) 22
Q.7 B Q.17 B Q.27 C
Q.25 ABO blood system is an example
of: Q.8 B Q.18 A Q.28 A
A) Polygenes
B) Multiple genes
Q.9 C Q.19 A Q.29 C
C) Multiple Alleles Q.10 A Q.20 D Q.30 A
D) Multiple Mutation
10. Genetics (Part – II)
H. Know cell cycle and its phases.

Cell Cycle:
 Series
eries of growth and development steps a cell undergoes between its “birth”
 STAGES:
 Interphase
 Mitotic (M) phase

IINTERPHASE MITOTIC PHASE

 Cell
ell grows and makes a copy of  Cell
ell separates its DNA into two
its DNA sets and divides its cytoplasm,
forming two new cells.
 Period of non-apparent
apparent division  Period of apparent division

Interphase:
 Period of life cycle between two consecutive divisions (2 mitotic phases) i.e.
misleadingly resting phase
 STAGES: (3 principle stages)

AVERAGE TIME
PHASE
IN HUMANS
G1 phase 9 hours
S phase 10 hours
G2 phase 4.5 hours
M phase 30 minutes
Total 24 hours

 Gap 1 phase (G1)

 Cell grows physically larger
 Copies organelles
 Makes
akes the molecular building blocks it will need in later steps i.e.
enzymes and base units of DNA
 Synthesis phase (S)
 Cell
ell synthesizes a complete copy of the DNA in its nucleus
 Duplicates
uplicates a microtubule-organizing
microtubule organizing structure called the
centrosome which help separate DNA during M phase
centrosome,
  Gap 2 phase (G2)
 Cell grows more and store energy for chromosome movements
 Makes proteins,
proteins, RNA, microtubule units (for spindle)
 Begins to reorganize
reorganiz its contents
nts in preparation for mitosis
 Ends when mitosis begin
 Gap 0 phase (G0)
 Post mitotic cell can end the cell cycle during G1, entering G0
phase
 Remain for days, weeks, or the life time (nerve cells, cells of eye
lens)

I. Describe events of mitosis and

and meiosis along with their
significance.

MITOSIS
 Ensures same number of chromosomes in daughter cells as in parent cells.
 Daughter and parent cells are identical
 Take place in both haploid and diploid cells in body
 Continuous process
 1 parent cell = 2 daughter
dau cells
 MAJOR PHASES:
 Karyokineses – Division of nucleus
 Cytokinesis – Division of cytoplasm
Karyokinesis:
 FOUR PHASES:
 Prophase
 Metaphase
 Anaphase
 Telophase

The
he chromosomes in the nucleus each
consist of two connected copies,
called sister chromatids

Prophase

 Mitotic
itotic spindle starts to form
 Chromosomes
hromosomes start to condense and appear as thin threads (0.25
(0.25-50 μm long)
 Nucleolus
ucleolus disappears.
  Nuclear envelope breaks down
releasing the nuclear material
(chromosomes) in cytoplasm
(making it viscous).
 Chromosomes are fully
condensed.

Metaphase
 Chromosomes line up at
metaphase
hase plate, under tension
from mitotic spindle.
 Two
wo sister chromatids of each
chromosome are captured by
microtubules from opposite
spindle poles.

Anaphase
 Sister
ister chromatids separate and
are pulled towards opposite
poles of cell.
 Microtubules
icrotubules not attached
at to
chromosomes push two poles of
spindle apart, while kinetochore
microtubules pull chromosomes
towards poles.
Telophase
 Spindle disappears
 Nuclear
uclear membrane re-forms
re
 Nucleolus reappears
 Chromosomes de-condense
condense

Cytokinesis

 Animal Cell:
An actin contractile ring around middle of cell pinches inward, creating an
indentation called the cleavage furrow.
 Plant Cell:
Cell
ell plate forms down the middle of the cell, creating a new wall
(phragmoplast) that partitions it in two. Started in metaphase and completed
to fuse in telophase.

MEIOSIS
 Number of chromosomes is reduced to half in daughter cells as compared to
parent cell
 Daughter and parent cells are not identical
 Take place in diploid cells only
 Animals – at gamete formation
 Plants – at spores formation
 1 diploid parent cell = 4 haploid daughter cell
 CONSECUTIVE DIVISIONS:
 Meiosis I – Reduction division
 Meiosis II – Just like mitosis
 Meiosis – I

Prophase – I
 Longest phase
 Chromosomes behave as homologous chromosomes (SIMILAR, NOT
NECESSARILYY IDENTICAL).
IDENTICAL). Each diploid cell has 2 chromosomes of each type
one from each parent.
 Lack G-2 phase

1. LEPOTENE (few hours)

a. Chromosomes = visible, short and thick
b. Nucleus = increase in size
c. Chromosomes = start getting closer

2. ZYGOTENE (few hours)

a. Synapsis = Highly specific and pointed pairing of
homologous chromosomes starts
b. Bivalent/Tetrad = Each paired (not fused) complex structure

3. PACHYTENE (for days, weeks, years)

a. Synapsis = Completed
b. Chromosomes = more visible, short and thick
c. Crossing Over
ver = Non-sister
sister chromatids of homologous
chromosomes exchange their segments to
reshuffle genetic material in ch
chiasmata
formation

4. DIPLOTENE
a. Paired Chromosomes = repel each other
b. Separation = only remain united by chiastmata only

5. DIAKINESIS
a. Chromosomes
somes = Maximum condensation
b. Separation = completed (Only end points remain united)
Metaphase – I
 Spindles form
 Nuclear membrane disorganize
 Homologue pairs (bivalent/tetrad)—not
(bivalent/tetrad) not individual chromosomes
chromosomes—line up at
the metaphase plate for separation.
Anaphase – I
 Homologues pairs (bivalent/tetrad) separate to opposite ends of the cell.
(Sister
Sister chromatids stay together.)
together.
Telophase – I
 Chromosomes
hromosomes arrive at opposite poles of the cell.
 Nuclear
uclear membrane re-forms
re
 Chromosomes
hromosomes decon
decondense

Meiosis – II
 Cytokinesis
kinesis usually occurs at the same time as telophase I, forming two haploid
daughter cells.
 Cells experience small interphase without any DNA replication
 Simply called the mitosis of haploid cells i.e. all phases same as mitosis
 FEATURE MITOSIS MEIOSIS
Two cells, having the same Normally four cells, each with
End result number of chromosomes as the half the number of
parent chromosomes as the parent
Production of gametes (sex cells)
Cellular reproduction, growth,
Function in sexually reproducing
repair, asexual reproduction
eukaryotes
Reproductive cells of almost all
Where does it All proliferating cells in all
eukaryotes (animals, plants,
happen? eukaryotes
fungi, and protists)
Prophase I, Metaphase I,
Prophase, Prometaphase,
Anaphase I, Telophase I,
Steps Metaphase, Anaphase,
Prophase II, Metaphase II,
Telophase
Anaphase II, Telophase II
Genetics Identical to parent Not Identical to parent
Yes, normally occurs between
Crossing over
No each pair of homologous
happens?
chromosomes
Synapsis No Yes
Occurs in Telophase I and
Cytokinesis Occurs in Telophase
Telophase II
Does not occur in Anaphase I,
Centromeres split Occurs in Anaphase
but occurs in Anaphase II

J. Discuss meiotic errors (Down’s syndrome, Klinefelter’s

syndrome, Turner’s syndrome).

Non-disjunction
Inability of chromosome to separate after crossing over during anaphase &
telophase of meiosis

FEATURE DOWN’S KLINEFILTER’S TURNER’S

Sex Male or Female Male Female
Chromosome 21st Autosome Sex Chromosome Sex Chromosome
No of Trisomy Trisomy Monosomy
Chromosomes 2n + 1 = 47 2n + 1 = 47 2n -1 = 45
Gamete 24 Ova 24 Sperm 22 Egg
Abortions 1/40 0 1/18
Teen age mother = 1/1000
Births
40 years = 1/100 1/1500 1/600
Frequency
45 years = 3/100
 Phenotypically male  Often do not survive
 Flat, broad Face with enlarged breasts pregnancy
 Squint Eyes with skin  Tendency to tallness  Aborted mostly
folded in the inner  Obesity  If survived have female
Affected corner  Small testes appearance
Individuals  Protruding tongue  No sperms at  Short stature
 Mental retardation ejaculation  Webbed neck
 Defective  Underdevelopment of  No ovaries
development of CNS secondary sex  Absences of germ cells
characters (Complete)
Chromosomal
45 autosome + XY 44 autosome + XXY 44 autosome + Y
Relation
 Patau (M/F) Edward (M/F) Metafemale (F) Jacobs (M)
Trisomy 13 Trisomy 18 Trisomy (XXX) Trisomy (XYY)

Apoptosis and
nd Necrosis
FEATURE APOPTOSIS NECROSIS
Apoptosis (Greek word: dropping
off or falling off) is internal Cell death due to tissue damage is
programme of events and called necrosis. It damages
Definition
sequence of morphological neighbouring cells and cause
chang by which cell commits
changes inflammations.
suicide.
Other Name Cell Suicide Cell Murder
Role Beneficial Harmful
Release of intracellular
No Yes
constituents

Cancer
 Cancer is uncontrolled cell division.
 Tumor is unwanted clone of cells, which can expand indefinitely.
 They are of two types
i. Benign tumors are localized and not transferred to other parts; cells behave
like normal and have little deleterious effects.
ii. Malignant tumors invade surrounding tissue, divide rapidly and metastasize
 Metastasis:
Metastasis: Spread of tumor cells and establishment of secondary
areas of growth.
 Malignancy:
Malignancy: Presence of invading cells in an otherwise normal tissue
 Cancer cells are less differentiated,
differentiated, high nucleus to cytoplasmic ratios, prominent
nucleoli and much mitosis.

TEST YOUR SELF

Q.1 When chromosomes uncoil, the A) Crossing Over

nucleoli are reformed and two B) Attachment
nuclei are the two poles of the cell; C) Pairing
stage is known as D) Leptotene
A) Prophase
B) Metaphase Q.4 Healing of a wound and repair is the
C) Telophase phenomenon which takes place by
D) Anaphase the process of
A) Mitosis
Q.2 Mental retardation, short stature, B) Meiosis
broad face and squint eyes are C) Cell Growth
symptoms of D) Mitosis & Meiosis
A) Down’s syndrome
B) Klinefelter’s syndrome Q.5 Which one of the followin
following is the
C) Turner’s syndrome main cause of cancer?
D) XYZ syndrome A) Mutation
B) Controlled Cell Division
Q.3 Chiasmata formation takes place C) Regulated Mitosis
during
ng the process which
w is known D) Haploid Division
Q.6 In which phase of the cell division Q.14 The most critical phase of mitosis
the metabolic activity of the which ensures equal distribution of
nucleus is high? chromatids in the daughter cells is
A) Mitosis A) Prophase
B) Interphase B) Metaphase
C) Meiosis C) Anaphase
D) Cell Cycle D) Telophase

Q.7 Exchange of segments between Q.15 Non-disjunction of 21st pair of

homologous chromosomes is called chromosomes in one of the gamete
A) Segregation leads to 47 chromosomes in one
B) Independent assortment individual. This condition is called
C) Crossing over A) Turner’s syndrome
D) Mutation B) Klinefelter’s syndrome
C) Down’s syndrome
Q.8 If a person has 44 autosomes + XXY, D) Jacob’s syndrome
he will suffer from
A) Klinefelter’s syndrome Q.16 During maternal mitosis, non-
B) Down’s syndrome disjunction of autosomal
C) Turner’s syndrome chromosome pair results in the
D) Edward’s syndrome formation of an egg having 24
Q.9 In which stage of Interphase, there chromosomes in:
is increase in cell size and many A) Klinefelter’s Syndrome
biochemical are formed? B) Down’s Syndrome
A) G2 phase C) Turner’s Syndrome
B) G1 phase D) Jacob’s Syndrome
C) S phase
D) C phase Q.17 Typical symptoms like enlarged
breasts and small testis in male are
Q.10 In Down’s syndrome, which one of attributed to:
the following pair of chromosome A) Down’s Syndrome
fails to segregate? B) Turner’s Syndrome
A) 7 C) Klinefelter’s Syndrome
B) 18 D) Phenylketonuria
C) 21
D) 19 Q.18 Turner’s syndrome is characterized
by having:
Q.11 Down's syndrome is a result of non- A) Trisomy 21
disjunction of ______ pair of B) 44 + XXY
chromosomes that fails to C) Trisomy 18
segregate: D) 44 + XO
A) 21st
B) 22nd Q.19 The disease in which an individual
C) 18th has extra sex chromosome (44 +
D) 24th XXY) is known as:
A) Down’s syndrome
Q.12 During animal cell division, the B) Tuner’s syndrome
spindle fibres are formed from C) Klinefelter’s syndrome
A) Mitochondria D) Jacob’s syndrome
B) Centrioles
C) Ribosomes Q.20 Down’s syndrome is characterized
D) Lysosomes by __________ at chromosome 21.
A) Trisomy
Q.13 During which period of interphase B) Monosomy
(cell cycle) DNA is synthesized? C) Polysomy
A) G1 D) Disomy
B) G2
C) S
D) G0
Q.21 Which of the following is an
example of autosomal non-
disjunction?
A) Turner’s Syndrome
B) Jacob’s Syndrome
C) Metastasis
D) Down’s syndrome

Q.22 Infertility, short height, webbed

neck and low hairline at lack are
symptoms of syndrome?
A) Turner’s
B) Down’s
C) Edward’s
D) Patau’s

Q.1 C Q.9 B Q.17 C

Q.2 A Q.10 C Q.18 D
Q.3 A Q.11 A Q.19 C
Q.4 A Q.12 B Q.20 A
Q.5 A Q.13 C Q.21 D
Q.6 B Q.14 C Q.22 A
Q.7 C Q.15 C
Q.8 A Q.16 B