BIOLOGY

EOY REVISION Chapters 1-10

CELL STRUCTURE AND

TOPIC OVERVIEW ORGANIZATION
A.​ Cell Structure and Organization
a.​ Cells
A CELLS
b.​ Adaptation and Functions
B.​ Movement of Substances
a.​ Diffusion
b.​ Osmosis
★​ building blocks of life
c.​ Active Transport ★​ characteristics of life
C.​ Biological Molecules
a.​ Carbohydrates
b.​ Fats A1 MICROSCOPE
c.​ Proteins
D.​ Enzymes
a.​ Description ★​ light (2000x magnification)
b.​ Characteristics ★​ electron (500,000x or more ‘’)
E.​ Nutrition in Humans ★​ pictures taken through this are called
a.​ Organs Associated with Food
micrographs
b.​ Organs Associated with the Gut
c.​ Digestion
d.​ Absorption A2 HISTOLOGY
e.​ Absorbed Nutrients
f.​ Effects of alcohol consumption
F.​ Transport in Humans
★​ Transverse
a.​ Components of Blood
b.​ Blood Groups ○​ cutting right angles along the
c.​ Blood Vessels Adaptation longitudinal plane
d.​ Blood Circulation
e.​ Heart Diseases
G.​ Respiration in Humans
a.​ Respiration
b.​ Gas Exchange
c.​ Breathing
d.​ Effects of Tabacco
H.​ Excretion in Humans
a.​ Organs Associated with Food
b.​ Organs Associated with the Gut
c.​ Digestion
d.​ Absorption
e.​ Absorbed Nutrients ★​ Longtitudinal
f.​ Effects of alcohol consumption
○​ cutting along the axis of the
I.​ Homeostasis and Hormone Control
a.​ Homeostasis cell
b.​ Control of Hormones
c.​ Maintaining Constant Temperature
J.​ Nervous System in Humans and Eye
a.​ Structure of Nervous System
b.​ Structure of the Eye
c.​ Sight

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A3 STRUCTURE BIOLOGICAL MOLECULES

Cell A CARBOHYDRATES
★​ consists of protoplasm
○​ cell surface membrane
★​ Organic molecules
○​ cytoplasm
★​ Made of C, H, O
○​ nucleus ★​ H:O = 2:1 ratio

Cell Surface Membrane Functions

★​ plasma membrane ➔​ Provide energy for cell activities
★​ partially permeable ➔​ Form supporting structures
★​ controls substance leaving and ➔​ Conversion into organic compounds
entering the cell ➔​ Form nucleic acids (e.g. DNA)
➔​ Synthesise lubricants
Cytoplasm ➔​ Synthesise nectar in flowers
★​ where most cell activities occur
★​ contains organelles: A1 SUGARS

Nucleus ➔​ Sweet and soluble in water

★​ contains: ➔​ Lowers water potential
○​ nucleoplasm, ➔​ Provides energy
○​ one or more nucleoli, and
○​ chromatin Monosaccharides (Simple Single Sugars)
■​ network of thread-like ➔​ Basic unit
structures ➔​ Can pass through cell membranes
■​ controls cell activities
■​ has DNA (hereditary ★​ Glucose
○​ Found in plants & animals
info.)
○​ Hexagon structure (6)
■​ condenses to ○​ Blood sugar: energy source for
chromosomes during most cells
cell division ★​ Fructose
★​ surrounded by nuclear envelope ○​ Common in plants, rare in animals
○​ Pentagon structure (5)
Cell Wall ○​ Fruit sugar: converts to glucose &
★​ present in plant cells only is metabolised
★​ fully permeable ★​ Galactose
★​ made of cellulose ○​ Found in plants & animals
○​ Hexagon structure (6)
★​ protects cell from injuries and gives
○​ Converts to glucose &
cell a uniformed shape metabolised

Disaccharides (Simple Double Sugars)

B ADAPTATIONS AND FUNCTIONS ➔​ Formed through condensation
➔​ E.g., glucose + glucose = maltose + water

❖​ Break down through hydrolysis

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❖​ E.g., maltose + water = (broken down by ○​ Protects plant cells from bursting
the enzyme maltase) to glucose + or damage
glucose ○​ Cannot be digested
○​ Has dietary fibre that prevents
★​ Maltose = Glucose + Glucose constipation
○​ Malt sugar ○​ Present in the cell walls of plants
○​ Product of starch digestion
★​ Sucrose = Fructose + Glucose
○​ Cane sugar, Table sugar
★​ Lactose = Galactose + Glucose Hydrolysis of Starch
○​ Milk sugar ➔​ Amylase breaks starch into maltose
○​ Important in infant nutrition ➔​ Maltase breaks maltose into glucose

*All monosaccharides and disaccharides (except

sucrose) are reducing sugars. A2 TESTS

Polysaccharides (Complex Sugars) Testing for Reducing Sugars: Benedict’s Test

➔​ made up of a long chain of glucose ➔​ 2cm³ of Benedict’s Solution to the same
molecules measure of food sample
➔​ Shake mixture
★​ Starch ➔​ Heat in a boiling bath for 2-3 minutes
○​ Storage form of carbohydrates in
plants Results:
○​ Found in the storage organs of ➢​ Blue - no reducing sugar
plants ➢​ Green - traces
○​ Digested to glucose (to provide ➢​ Yellow/orange - moderate amount
energy) ➢​ Red - large amount

Testing for Starch: Iodine Test

➔​ 2cm³ of food sample into a clean test
★​ Glycogen tube
○​ Storage form of carbohydrates in ➔​ Add a few drops of iodine
animals
○​ Found in the liver and muscles of Result:
mammals ➢​ Blue-black - starch present
○​ Digested to glucose (to provide ➢​ Brown - starch absent
energy)

B FATS

★​ Type of lipid
★​ Organic molecules
★​ Made of C, H, O
★​ Less oxygen in proportion to hydrogen
★​ Not fixed proportions

Functions
➔​ Source and storage of energy
➔​ Insulating material to prevent excessive
★​ Cellulose heat loss

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➔​ Solvent for fat-soluble vitamins and ★​ Omnipresent in all cells

some hormones ★​ Smaller basic unit: amino acids
➔​ Forms the main part of the cell
membrane ➔​ Synthesises new protoplasm for cell
➔​ Reduce water loss from the skin surface growth
➔​ Repair worn-out cells
➔​ Synthesises enzymes and some
B1 FAT MOLECULE
hormones
➔​ Synthesises antibodies
➔​ Glycerol
➔​ Fatty acid chains
C1 FORMATION
➔​

★​ AAs are building blocks

★​ Peptide bonds link AAs to form a
polypeptide
★​ 2 ≥ polypeptide chains fold to form a 3-D
molecule (protein)

Hydrolysis of Fat
➔​ Produces glycerol and fatty acids

C2 AMINO ACIDS

★​ Building blocks
★​ Made up of
○​ Amino group
B2 TEST ○​ Acid group
○​ Side chain
Testing for Fats: Ethanol Emulsion Test
➔​ 2cm³ of ethanol to the same measure of
food sample
➔​ Shake tube vigorously
➔​ Decant 3cm³ of water into test tube
➔​ Shake mixture

Results:
➢​ Cloudy white - fats present
➢​ Clear - fats absent

C2 TEST
C PROTEINS

Testing for Proteins: Biuret Test

★​ Organic molecules ➔​ 2cm³ of sodium hydroxide to the same
★​ Made of C, H, O, N measure of the food sample
(sulfur may be present) ➔​ Shake mixture thoroughly

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➔​ Add 1% of copper(II) sulfate solution drop *remember, fat is hydrolysed into fatty acid &
by drop glycerol
➔​ Shake the mixture after each drop
Examples of Digestion
Results: ❖​ Amylase - starch to maltose
➢​ Violet - proteins present ❖​ Maltase - maltose to glucose
➢​ Blue - proteins absent ❖​ Protease - proteins to amino acids
❖​ Lipase - fats to fatty acids and glycerol

ENZYMES
C2 ANABOLIC REACTIONS
★​ A protein
★​ Functions as a biological catalyst (A/C) ★​ Building up of complex substances
★​ Lowers activation energy (B) ★​ Proteins from amino acids
★​ Required in minute amounts
★​ Highly specific in action (D)
C3 CATABOLIC REACTIONS

A BIOLOGICAL CATALYSTS
★​ Breakdown of complex substances
★​ Glucose during respiration
★​ Alter or speed up a chemical reaction
★​ Isn’t chemically changed at the end of
D HIGH SPECIFICITY
the reaction

B ACTIVATION ENERGY ★​ A unique enzyme catalyses each reaction

★​ This is due to its 3-D shape

★​ Needed to start a chemical reaction Lock-and-Key Hypothesis

★​ Substrate (key) can fit into the enzyme's
active site (lock)
★​ Active site - where the substrate
attaches
★​ Substrate - a specific molecule that the
enzyme works on
★​ This formation makes an
enzyme-substrate complex
★​ After the reaction, the substrate becomes
products
C CATALYSED REACTIONS
★​ Products leave the site, and the enzyme
is used again for another substrate

C1 DIGESTION

★​ Some food molecules are large and

insoluble in water
★​ Cannot diffuse across the cell
membrane,
★​ ​have to be converted or digested into
smaller, simpler molecules to do so

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■​ If not at the optimum pH

level, the enzyme
denatures.

NUTRITION IN HUMANS

★​ The process by which organisms obtain

food and energy for the growth, repair,
and maintenance of the body.

Process
➔​ Ingestion (feeding)
◆​ Food taken into the body
➔​ Digestion
◆​ Large food molecules are broken
down (into smaller, soluble ones)
Denaturation ➔​ Absorption
★​ Causes the active site to change shape ◆​ Nutrients move (from the small
★​ Factors include: intestine) into the bloodstream
○​ Change in Temperature ➔​ Assimilation
■​ Very low - inactive ◆​ Conversion of energy or making
■​ Low - low kinetic energy new cytoplasm
■​ Optimum - collision of ESC ➔​ Egestion
■​ Very high - denature ◆​ Undigested matter is removed
from the body

A ORGANS ASSOCIATED WITH FOOD

Human Digestive System

★​ Consists of:
○​ Gut (or alimentary canal) and
○​ Organs

○​ Change in pH Level

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*Carbohydrase - a type of enzyme that breaks

down carbohydrates into simple sugars
E.g. Amylase and Maltase

A2 PHARYNX

★​ Connects the buccal cavity to the

esophagus and the larynx (voice box)
★​ Leads to the trachea (windpipe)

Gut (alimentary canal)

★​ 9 meters of road in the body

➔​ Mouth (and buccal cavity)

➔​ Pharynx (throat area)
➔​ Esophagus (food pipe)
➔​ Stomach
➔​ Small intestine (duodenum, jejunum, ★​ During breathing, the larynx is lowered,
ileum) and the glottis opens
➔​ Large intestine (colon and rectum) ★​ During swallowing, the larynx is raised,
➔​ Anus and the glottis is covered by the
epiglottis
Organs
➔​ Liver
➔​ Gall bladder
➔​ pancreas

A1 THE MOUTH AND BUCCAL CAVITY

★​ Food -> mouth -> buccal cavity *This prevents choking and food from entering
★​ Mouth - entrance + space the trachea (windpipe)
○​ Physical digestion
○​ Chemical digestion A3 THE OESOPHAGUS
(Carbohydrase*)
★​ Buccal cavity - mainly the inner space for
digestive work ★​ Aka gullet
★​ The buccal cavity is the beginning of the ★​ Narrow and muscular tube
alimentary canal ★​ Connects the mouth and stomach

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★​ Consists of muscle layers ◆​ Hydrochloric acid

○​ Longitudinal - outer side ●​ pH level of ~1.5-3.5
○​ Circular - inner side ●​ kills microbes
◆​ Pepsinogen
*Both muscles are present along the whole gut ●​ inactive enzyme
(oesophagus to the rectum). ●​ activated by HCl to pepsin
●​ digests proteins into
Peristalsis peptides
➔​ Rhythmic, wave-like muscular ◆​ Mucus
contractions in the alimentary canal wall ●​ continuously secreted
➔​ Enables food to be mixed with digestive ●​ protects the stomach
juices lining from self-digestion
➔​ Helps to push or propel the food along and acid
the gut
➔​ Antagonistic movement (opposite)
A5 THE SMALL INTESTINE
Contract & Relax - refers to muscles
Constricts & Dilates - refers to the lumen space ★​ 6 metres long organ
★​ Most digestion and absorption of
Detailed Process nutrients occur here
Before the bolus (food mass)
➔​ Longitudinal muscles: relax Parts
➔​ Circular muscles: contract Duodenum (~25cm)
➔​ Lumen Space: constricts ➔​ First section
➔​ Receives
At the bolus ◆​ Chyme from the stomach
➔​ Longitudinal muscles: contract ◆​ Bile from the liver
➔​ Circular muscles: relax ◆​ Pancreatic juice from the
➔​ Lumen Space: dilates. pancreas
➔​ Major site for chemical digestion
A4 THE STOMACH
Jejunum (~2.5cm)
➔​ Middle section
★​ Located on the left side of the ➔​ The main site of nutrient absorption
abdominal cavity
★​ Partly covered by the liver Ileum (~3.5m)
★​ Has numerous gastric pits with gastric ➔​ Final section
glands -> secretes gastric juice ➔​ Absorbs remaining nutrients (e.g. bile
★​ Serves as a temporary storage site for salts, vitamin B12)
food
★​ Mechanical and physical digestion
Main Functions
Mechanical Digestion Digestion
➔​ Muscular walls churn the food to mix it ➔​ Enzymes from the pancreas and
with gastric juices intestinal walls digests carbohydrates,
➔​ Turns food into chyme (semi-liquid proteins, and fats
mixture)
Absorption
Chemical Digestion ➔​ Nutrients are absorbed through the
➔​ Gastric glands secrete lining into

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◆​ Blood capillaries
Enzyme Substrate Product
(sugars, amino acids)
Maltase Maltose Glucose
◆​ Lacteals
(fats) Sucrase Sucrose Glucose +
Fructose
Transport
➔​ Moves chyme slowly to give ample time Lactase Lactose Glucose +
for 2 main processes Galactose

Peptidase Peptides Amino acids

Adaptations for Absorption
Feature Function Lipase (from Fats Fatty acids +
the pancreas) glycerol
Villi Finger-like projections ->
increases surface area End Products Absorbed
➔​ Glucose, amino acids = blood capillaries
Microvilli Tiny projections on villi -> even ➔​ Fatty acids, glycerol = lacteal
more surface area ➔​ Vitamins, minerals = blood

Thin walls One-cell thick for efficient

diffusion A6 THE LARGE INTESTINE

Rich blood Transports nutrients quickly ->

supply maintains diffusion gradient ★​ Final part of the digestive system
★​ Absorb water and minerals
Lacteals Absorbs fatty acids and ★​ Form and store feces
glycerol into the lymphatic ★​ ~1.5m long, wider in diameter,
system comparable to the small intestine

Parts
Digestive Juices Involved ➔​ Caecum
Source Secretions Function ◆​ Where the appendix is
➔​ Colon
Liver Bile (stored in the Emulsify fats ➔​ Rectum
gallbladder) for easier ◆​ Temporary storage site for feces
digestion ➔​ Anus
◆​ Exit of feces via egestion
Pancreas Pancreatic Digests
enzymes carbs,
B ORGANS ASSOCIATED WITH THE GUT
(amylase, lipase, proteins, and
trypsin) fats
★​ Not part of the main digestive track
Intestinal Intestinal Final ★​ However, assists in the digestion process
Glands enzymes (e.g., breakdown through its secretions
maltase, of nutrients
peptidase)
B1 THE SALIVARY GLANDS

Enzymes in the Small Intestine

★​ Located in the mouth

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★​ Secretes saliva that contains:

○​ Amylase
■​ pH level 7 (neutral)
■​ Starch into maltose
○​ Mucus
■​ Moistens and lubricates
food
★​ Starts a chemical reaction by forming the
bolus

B2 THE LIVER
Breakdown of Hormones
★​ Largest organ ➔​ Hormones are broken down once they’ve
★​ Digestion and regulation served their purpose in the liver
➔​ Hormones are
Production of Bile ◆​ Chemical substance produced (in
➔​ Bile emulsifies fats - globules to small very small amounts) by the
droplets endocrine gland
➔​ Provides an alkaline environment in the ◆​ Can influence growth,
S.I. for enzyme activity development, and activity
◆​ Chemical messengers
Deamination of Amino Acids
➔​ Excess amino acids are transported to Detoxification
the liver ➔​ Harmful substances absorbed are made
➔​ Amino groups are removed and harmless by the liver cells
converted to urea ➔​ Breaks down alcohol
➔​ Urea is removed through urine ➔​ Has an enzyme that converts alcohol into
➔​ Remains of the deaminated AA are compounds for respiration
converted into glucose
➔​ Excess glucose is converted to glycogen

Regulation of Blood Glucose Concentration

➔​ Carbohydrate metabolism
➔​ The amount of glucose in the blood is to
be constant
➔​ The pancreas secretes the hormonal
insulin and glucagon into the
bloodstream to regulate glucose levels

TRANSPORT IN HUMANS

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■​ involved in immune
A COMPONENTS OF BLOOD
defense (antibodies)
○​ Fibrinogen
■​ essential for blood clotting
A1 PLASMA

A2 RED BLOOD CELLS

★​ yellowish liquid
★​ contains:
○​ mainly water ★​ circular, biconcave shape w/o nucleus
○​ blood cells ★​ has red pigment (haemoglobin)
■​ around the body ★​ flexible
○​ excretory products
■​ e.g: urea, CO₂ acid Functions
■​ to excretory organs for Transports…
removal ➔​ oxygen from the lungs to other parts of
○​ substances the body
■​ glucose, amino acids, fats,
salts, hormones, vitamins Adaptations
■​ nutrients from small ➢​ haemoglobin can combine reversibly
intestine to other parts of with oxygen
the body
■​ hormones from endocrine [insert img and expla]
glands to target organ
➢​ biconcave shape increases surface
area-to-volume ratio (increasing rate of
Functions absorption and release of oxygen)
Transports… ➢​ flexibility and ability to turn bell-shaped
➔​ blood cells around the body for easy flow through narrow blood caps
➔​ nutrients from small intestines to other ➢​ no nucleus allows more space for
parts of the body haemoglobin to be stored
➔​ excretory products from organs to
excretory organs
A3 WHITE BLOOD CELLS
➔​ hormones from endocrine glands to
target organs
★​ crucial part of immune system
Adaptations ★​ circulates in the blood and lymphatic
➢​ high water content system, defending the body against
○​ water is an excellent solvent infection, illness, and disease
○​ allows plasma to dissolve and ★​ produced in the bone marrow
carry nutrients, hormones, and
waste products Functions
○​ fluid nature enables easy flow ➔​ phagocytes
through blood vessels ◆​ phagocytisis
➢​ carries plasma protein ●​ englfs and destroys
○​ Albumin pathogens (bacteria, etc.)
■​ maintains osmotic ➔​ lymphocytes
pressure ◆​ produces antibodies that:
■​ prevent excessive fluid loss ●​ recognises and destroys
from capillaries into tissues pathogens
○​ Globulins

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●​ causes pathogens to ○​ easily stick to broken surfaces of

clump together for easy blood vessels
ingestion by phagocytes ➢​ no nucleus
●​ neutralise the toxins ○​ more space for clotting factors
produced by bacteria and quicker response
➢​ contain clotting factors in cytoplasm
Adaptations ○​ initiate clotting cascade to form
➢​ Phagocytes fibrin mesh
○​ iIrregular shape to squeeze ➢​ surface proteins
through capillary walls into ○​ help them stick to each other and
tissues to damaged vessel walls
○​ flexible membrane to engulf
pathogens
○​ cytoplasm contains lysosomes A5 BLOOD CLOTTING
with enzymes to digest
pathogens ★​ blood exposed to air will soon clot or
○​ can detect and move towards coagulate*
chemicals from pathogens ★​ clotting seals the wound
(chemotaxis) ★​ prevents
➢​ Lymphocytes ○​ excessive loss of blood
○​ large, round nucleus to produce ○​ pathogens to enter the
antibodies bloodstream
○​ some differentiate into memory ★​ haemophilia
cells for faster response to the ○​ blood clotting mechanism is
same pathogen in future greatly impaired
○​ antibodies attach to antigens on
pathogens to neutralise or destroy Clotting Process
them ➔​ platelets covert soluble protein
(fibrinogen) to insoluble threads (fibrin)
A4 PLATELETS ➔​ fibrin threads entangle blood cells and
the whole mass, forming a clot (or scab)
[insert img]
★​ small, cell fragments (not full cells) found
in blood
★​ made in bone marrow from large cells A6 ORGAN TRANSPLANT AND TISSUE
REJECTION
called megakaryocytes
★​ no nucleus
★​ recall role of white blood cells
Functions ★​ in some medical procedures (e.g. organ
➔​ help blood clot transplant, blood transfusion), the
◆​ prevent excessive bleeding when immune system may recognise the
blood vessels are damaged donated organ or blood as foreign
➔​ form a temporary plug and trigger a ★​ this can lead to tissue rejection
chain of chemical reactions (clotting ★​ tissue matching (e.g. matching blood
cascade) leading to formation of a fibrin groups) is important to reduce the risk of
mesh. rejection

Adaptations
➢​ small, irregular shape​ B BLOOD GROUPS

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C BLOOD VESSELS ADAPTATION

B1 FOUR GROUPS

C1 CIRCULATORY SYSTEM
Blood Groups Table

Made up of…
➔​ heart
➔​ blood vessels
◆​ arteries/arterioles
◆​ blood capillaries
◆​ vein/venule

★​ antigens are on the surface of the RBC

★​ antibodies are in the blood plasma,
produced by WBC
Structure and Functions
Mixture of Blood Groups Table Artery
★​ thick, muscular, and elastic wall
○​ to withstand high blood pressure
★​ elasticity helps artery wall to stretch n
recoil
★​ contraction and relaxation of arterial
walls
○​ diverts blood to certain organs
★​ agglutination happens when blood ○​ e.g. dilation of arterioles of the
clumps together (blocks blood vessels) skin to divert blood to skin
capillaries during
thermoregulation
→ has clumping (agglutinaion)
→ blood groups are incompatible

→ no clumping
→ blood groups are compatible

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Factors affecting Diffusion:

➔​ Temperature*
➔​ Surface area
➔​ Diffusion distance
➔​ Steep concentration gradient
*does not matter since constant in body

Vein
★​ has tissue
★​ thin, (some) muscular, and (little) elastic
wall
○​ blood flows more slowly and
smoothly (compared to arteries)
★​ has valves to prevent backflow (due to
gravity)
Blood Capilliary ★​ transports blood back to the heart
★​ walls: partially permeable, one-cell thick
○​ enable efficient diffusion of
certain substances
○​ in: oxygen, glucose, amino acids,
hormones, nutrients
○​ out: carbon dioxide, urea,
metabolic wastes
★​ vessels: tiny and numerously branched to
○​ increase the surface area for
exchange of substances
○​ increase the total cross-sectional
area of the blood vessels––slowing
blood down for substance
exchange
★​ formed by branched out small arteries

Note !

Adaptations must ensure that:

➔​ surface area is maximised

Micrograph of Transverse Sec. of Art. n Vein
➔​ diffusion distance is minimised
➔​ concentration difference is maximised

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★​ colourless fluid that filled the spaces

between cells in tissue
★​ transport dissolved substances between
blood capillaries and tissue cells

D BLOOD CIRCULATION

➔​ the circular shape with more muscles is D1 CIRCULATORY SYSTEM

the artery
➔​ the triangular shape with more lumen
space is the vein Double Circulation

C2 SITTING FOR LONG

Movement of blood:
→ From the heart to the
lungs to the heart
→ From the heart to the
rest of the body back to
the heart
→ In a double circulation,
the blood has to pass
through the heart twice in
one complete circuit.

➔​ sitting for too long without much

movement can build pressure up in the
veins of the lower limbs
➔​ causes poor blood circulation and blood
to pool in the legs
➔​ skeletal muscles and movement are
important to ensure blood returns to the
heart

C3 TISSUE FLUID

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Blood Vessels around the Body

D2 PARTS OF THE HEART

➔​ semi-lunar valve:
◆​ aortic (L)
◆​ pulmonary (R)
➔​ tricuspid valve
Through and From the Heart ◆​ 3 flaps
➔​ upper vena cava ◆​ Right
➔​ lower ‘’ ➔​ bicuspid valve
➔​ pulmonary vein ◆​ 2 flaps
➔​ ‘’ artery ◆​ Left
➔​ aorta
D3 HOLE IN THE HEART
Through and From the Lungs
➔​ pulmonary vein
➔​ ‘’ artery

Through and From the Liver

➔​ hepatic vein
➔​ ‘’ portal vein
➔​ ‘’ artery

Through and From the Kidneys

➔​ renal vein
➔​ ‘’ artery

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★​ hole in the median septum will cause the

mixing of oxygenated and deoxygenated
blood
★​ this reduces the concentration gradient 1 - slight increase of ventricular pressure as atrial
of oxygen and carbon dioxide, reducing muscles contract, forcing blood to the ventricles
gas exchange efficiency
★​ possible condition: shortness of breath, 2 - ventricluar muscles start to contract; BC
fatigue, and heart failure
3 - ventricular muscles continue to contract,
volume of blood does not change, pressure rises
D4 CARDIAC CYCLE
4 - ventricular pressure becomes higher than
Systole aorta; SO (aortic valve); blood volume in ventricle
★​ contraction lowers as it is forced out of aorta
★​ Atrial and Ventricular
5 - ventricular muscles begin to relax, drop in
Diastole pressure closes the aortic valve
★​ relaxtion
★​ Atrial and Ventricular 6 - ventricular muscles continue to relax, no
change in blood volume
Process
➔​ Atrial muscles contract, Ventricular 7 - ventricular pressure becomes lower than
muscles relax atrium; BO
➔​ Ventricular muscles contract, Atrial
muscles relax 8 - ventricular pressure slightly increases as
➔​ Both muscles relax blood from atrium comes in

Graph - Ventricle E HEART DISEASES

Coronary Heart Disease

★​ fatty deposits that narrows the lumen
space

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EOY REVISION Chapters 1-10

★​ muscle cells carry out anaerobic

RESPIRATION IN HUMANS respiration to meet demand through
Lactic acid.
★​ the small amt of energy from anaerobic +
A RESPIRATION large amt of energy from aerobic = meets
the energy demand (for continued
★​ breakdown of food molecules to glucose muscle contraction)
for release of energy ★​ the insufficient oxygen causes muscles to
★​ occurs in the mitochondria (powerhouse) incur oxygen debt

Oxygen Debt
A1 AEROBIC ➔​ amt of oxygen required to remove lactic
acid through
◆​ continuation of fast heart rate
★​ presence of oxygen
●​ continued & fast transport
of lactic acid from muscles
Word Equation
to liver and oxygen from
glucose + oxygen -----> water + large amt of
lungs to liver
energy + carbon dioxide
◆​ ‘’ of deeper and faster breathing
●​ continued & fast intake of
Chemical Equation
oxygen by lungs to remove
𝐶6𝐻12𝑂6 + 6𝑂2 −> 6𝐻2𝑂 + 6𝐶𝑂2 + 𝑒𝑛𝑒𝑟𝑔𝑦 (𝑙𝑎𝑟𝑔𝑒 𝑎𝑚
lactic acid from blood
➔​ once lactic acid is removed, debt is paid
A2 ANAEROBIC
A4 BREATHING VS RESPIRATION

★​ no oxygen
Breathing
Word Equation ★​ movement of air in and out of lungs
glucose + lactic acid + small amt of energy
Respiration
Chemical Equation ★​ cellular respiration
𝐶6𝐻12𝑂6 −> 2𝐶3𝐻4𝑂2 + 𝑒𝑛𝑒𝑟𝑔𝑦 (𝑠𝑚𝑎𝑙𝑙 𝑎𝑚𝑡)

A4 STUDYING RESPIRATION
A3 VIGOROUS ACTIVITIES
Test for presence of 𝐶𝑂2 - Aerobic
★​ muscle cells aerobically respire at a high
rate
○​ causes panting to remove 𝐶𝑂2
○​ faster heart beat
★​ however, there is a limit to the increase in
rate of breathing and heartbeat
★​ when it continues, muscle contractions
are so vigorous that maximum aerobic
respiration cannot meet energy demand

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 BIOLOGY
EOY REVISION Chapters 1-10

Test for presence of 𝐶𝑂2 - Anaerobic;

Fermentation

★​ nasal passages
★​ pharynx
★​ larynx
★​ trachea
★​ bronchi*
★​ bronchioles*
★​ alveoli*
★​ thoracic cavity
★​ ribs
B GAS EXCHANGE ★​ diaphragm
*part of the lungs

★​ exchange of games between an The Nose

organism and the environment ➔​ external nostrils
★​ unicellular organisms have large surface ➔​ walls are fringed with hair
area-to-volume ratio for gas exchange ◆​ traps dust, foreign particles, and
○​ occurs through diffusion bacteria
★​ humans and complex organisms have ➔​ nostrils lead to nasal passage
relatively small surface area ◆​ lined with moist mucous
○​ hence, needs special organs for membrane
gas exchange ◆​ the air passing is warm and moist,
preventing irritation
◆​ harmful chemicals may be
B1 GAS EXCHANGE SYSTEM
detected by small sensory cells

Parts of the System Nose to Trachea

➔​ nasal passage to pharynx
➔​ pharynx to larynx
➔​ larynx to trachea

Trachea
➔​ windpipe

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 BIOLOGY
EOY REVISION Chapters 1-10

➔​ supported by C-shaped cartilage rings

◆​ keeps lumen open
➔​ epithelium membrane is next to lumen
that has
◆​ gland cells - secretes mucus
◆​ ciliated cells - hair-like structures
named cilia
●​ sweeps dust-trapped
mucus towards pharynx to
be coughed out or
swallowed

Adaptation of Lungs for Efficient Gas Exchange

★​ numerous alveoli
■​ large surface area
★​ walls of aveoli
○​ one cell thick
■​ short diffusion distance
Bronchi and Bronchioles ○​ thin film of moisture on inner
➔​ two tubes separated by trachea walls
➔​ singular: bronchus ■​ allow for oxygen to
➔​ carries air into lungs dissolve
➔​ has similar structure to trachea ○​ surrounded by numerous blood
➔​ each bronchus branch produces capillaries
numerous bronchioles (v. fine tubes) ■​ maintain concentration
➔​ each bronchioles end with air sacs gradient
(alveoli)
B4 GAS EXCHANGE IN ALVEOLUS
B2 STRUCTURE OF ALVEOLI

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 BIOLOGY
EOY REVISION Chapters 1-10

B5 OXYGEN TRANSPORT AROUND THE

BODY

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