What is Biology?

▪ two parent organisms

from the Greek words:
bios = life
logos = study
• Biology is the science of life
• branch of science which deals with
the study of living things
2. Asexual
Why study Biology?
▪ does not
❑ It helps you understand your body require
❑ Helps you become an informed citizen sex cells
▪ single
❑ Biology can open career opportunities
parent
❑ Biology can enrich your appreciation of
▪ offspring
the world
produce is an
Characteristics of Living Things exact clone of its
parent
1. Living organisms are organized

❑ living things belong to a hierarchy of

different levels of organization
4.Living things respond to stimuli

❑ stimuli - detectable changes in the

environment
Example:
▪ leaves of touch-me-not plant bend when
touched
▪ moving away from fire due to heat
2. Living organisms acquire material &
5. Living things are homeostatic
energy
❑ the ability to maintain a stable internal
❑ acquired materials & energy are
environment despite the change in the
transformed into different forms
external environment
❑ e.g., energy used for growth &
reproduction
3. Living organisms reproduce

❑ ensures continuity & diversity of life

❑ hereditary traits are passed on from

parents to offspring

❑ two types 6. Living things grow and develop

1.Sexual ❑ by eating food and nutrients

▪ union of sperm (male) & egg cells (female) ❑ growth = increase in size or mass
– sex cells
 Classification that all living things share
How many animal and plant species on
Earth?

❑~8 million
species?

❑~2-3 million
species?
• 1.2 million
described
7. Living things can adapt to their species
environment • more
works has to be done
❑ allows populations to change over time in
response to changing environment Systematics

❑ adaptations - are traits that increase an ❑ field of biology that studies the diversity
organism’s ability to survive in its of organisms and their evolutionary
environment relationships

❑ discipline of identifying, classifying, and

naming organisms according to specific
criteria
▪ organisms are given a universal name
“scientific name”, following the Binomial
System of Nomenclature by Carolus
Linnaeus (Father of Taxonomy)

7. Living organisms can evolve ▪ e.g., Oryza sativa (rice) typewritten =

italicize, handwritten = underline
❑ e.g.,
giraffes' Categories in Classifying Life
long neck is ❑Five Kingdom System - proposed by
a product Robert Whittaker
of
adaptation - assigned organisms to different Kingdoms
to feed on 1. Monera
growing tress (Lamarck vs Darwin) 2. Protista
Characteristics of living things 3. Mycota
1. Organized 4. Plantae
2. Acquire energy 5. Animalia
3. Reproduce new category
4. Responsiveness higher than
Kingdom is
5. Homeostatic proposed,
6. Growth & Development DOMAIN (Carl
Woese, 1990)
7. Capacity to adapt
 Water has a major role in the Earth’s climate
& help determine whether certain places in
the world are fit to live in.
- e.g., fishes are able to thrive in a pond
because the water temperature stay
relatively the same throughout the day

The Process of Science

2. High heat of vaporization - high amount
of heat needed to vaporize water
Heat of vaporization is the amount of
energy needed to change one gram of liquid
substance to gas at a constant temperature
- for water, 540 cal/g at 100°C (boiling point)

3. High polarity - water is a polar molecule

attracting other polar molecules (universal
Scientific Method solvent)
• Observation - sugar (polar molecules) dissolved in water
• Identification of the Problem
Polar molecule – one end of the molecule is
• Formulation of hypothesis
slightly “+”, while the other end is slight “-”
• Experimentation
• Gathering of Data
• Interpret Data or Results 4.Molecules are cohesive & adhesive
• Formulation of Conclusion & Cohesion – attraction between two same
Recommendation molecules
• Publications of findings
Adhesion – attraction between different
Molecules and Compounds molecules
• Molecule - two or more atoms bond
together
5.High surface tension
Surface tension – property of liquid surface
that allow resistance to an external force
• Compound - atoms of two or more - water is cohesive, molecules at the surface
elements bond together of the water “stick together” forming a type
Chemistry of Water of “skin”, strong enough to support very
light objects
• Water - 70 – 90% of living material
- polar molecule composed of 2 hydrogen &
1 oxygen atoms 6. High heat of fusion

Polar molecule – one end of the molecule is Heat of fusion – amount of energy required
slightly “+”, while the other end is slight “-” to change the state of matter of a
substance, e.g., solid to liquid (a.k.a.
Properties of Water melting)
1.High heat capacity - water absorbs a lot of
heat before it begins to get hot
Properties of Water Organic Molecules: TYPES
1. High heat capacity 1. Carbohydrates
2. High heat of vaporization 2.Proteins
3. High polarity 3. Nucleic Acids
4. Molecules are cohesive & adhesive 4. Lipids
5. High surface tension 1. Carbohydrates - contains C, O & H joined
by glycosidic bond - general formula
6. High heat of fusion
(CH2O)n
Organic Molecules
- function:
- molecules normally found in living systems
→ energy sources for the cells
- always contain carbon (C) and hydrogen
→ serves as principal sugar transported
(H)
throughout land plants (sucrose)
covalent bond → electrons are shared
→ as energy storage (glycogen in animals &
between atoms
starch in plants)
Organic Molecules
- Types based on the number of
sugar/saccharide:
a. Monosaccharide → simple sugars,
monomer
b. Disaccharide → 2 monosaccharides
c. Oligosaccharide → 3-10 monosaccharides
d. Polysaccharide → long chain of
monosaccharides

a. Monosaccharide
- simple sugar (CH2O)n
- basic building blocks of carbohydrates,
direct source of metabolic energy
a.k.a the biological molecules of life
- consists of 3-7 C atoms
- like glucose, fructose, galactose

b. Disaccharide
- sugars with 2 monosaccharides joined
through dehydration synthesis
 2. Proteins
- composed of 1 or more long chains of
amino acids linked by peptide bonds
glucose + fructose = sucrose
- composed of 1 or more long chains of
- like sucrose, maltose, lactose
amino acids linked by peptide bonds
- contain 4 elements: -
functional groups:
R-group
c. Oligosaccharide
- variable
- 3-10 monosaccharides joined through
-determines
dehydration synthesis
the identity of
- common in soybeans & legumes the amino acid.
- common in soybeans & legumes
- e.g., stachyose & raffinose Stachyose
d. Polysaccharide
- polymers consisting very long chains of
monosaccharides joined through
dehydration synthesis
- e.g., starch (plant) & glycogen (animal)
as energy storage - function:
- e.g., cellulose in plants (most abundant → defense (antibodies)
macromolecules on Earth)
→ transport (hemoglobin, myoglobin)
- e.g., chitin in animals (like crustaceans)
→ support/structural (collagen, keratin)
→ motion (actin, myosin)
→ regulation (insulin, oxytocin)
→ storage (casein)
→ enzyme catalysis (hydrolytic enzymes)
- enzymes:
→ special proteins that speeds up
reactions
Note the way → its name indicates its function
complex Sucrase → degrades sucrose
macromolecule are
built by linking simple repeating units. Lactase → degrades sucrose degrades
lactose
Maltase → degrades maltose
3. Nucleic acids
- composed of chains of nucleotides
with 3 components linked by hydrogen
bonds:
 Nucleic acid other types
- nucleotides not part of DNA or RNA

- composed of chains of nucleotides with

3 components:

4. Lipids
- loosely defined groups of molecules
insoluble in water
- primarily composed of
- fatty acids (FA) &
glycerol (building
- functions: blocks) are held by
→ storage of genetic information ester linkage

→ transmission & use of genetic

material - functions:
- 2 types: → energy storage (2x more than
carbohydrates)
→ protection & cushioning of body
organs
→ structural components of membranes
→ chemical messengers (hormones)
Lipid groups

Monomer/ Polymer Bond

Building block
Monosaccharide Carbohydrate Glycosidic
bond
Amino Acid Protein Peptide
bond
Fatty acid, Lipid Ester
Nucleic acids base pairing glycerol Linkage
Nucleotide Nucleic acid Hydrogen
bond
The CELL

❑ basic and smallest unit of life

❑ first described by Robert Hooke (1665)

from a thin slice of cork
The Modern CELL Theory

❑ existing cells are descendants of the first

cells formed early in the evolutionary
history of life on Earth

❑ scientists behind Cell Theory:

- Matthias Schleiden (botanist)
- Theodor Schwann (zoologist)
- Rudolf Virchow (pathologist)
- Louis Pasteur (chemist & microbiologist) Cell: MOVEMENT * & PROTISTS
The Modern CELL Theory ❑ through locomotory structures
1. Every living cell is made up of one or
more cells.
2. Cells are the smallest complete living
organisms →the basic unit of organization
of multicellular organisms.
3. Cells arise only from pre-existing cells
through the process of cell division.
Cell: Shapes & Sizes
Cellular Organelles (little organs)
1. Mitochondria Function: energy
suppliers
2. Chloroplasts
3. Ribosomes Function:
4. Endoplasmic reticulum manufacturers

5. Golgi complex or apparatus

6. Lysosomes Function: digestion
Cell: Types based on structure 7. Vacuoles Function: storage and elimination
9. Nucleus Function: control/regulation

MITOCHONDRIA
- powerhouse of the cell
- site of cellular respiration/aerobic
metabolism
-have their own DNA & ribosomes
-self-replicating - amino acids that synthesize protein
- energy converting organelle a. Attached ribosome
- have enzyme assemblies that synthesize - make proteins for the membranes or
the energy- carrier molecule, ATP
- make proteins for exports
b. Free ribosome
- produces most proteins use in the
cytoplasm
- occurs freely in the cytoplasm
double-membraned organelle: GOLGI APPARATUS
(i) outer membrane - smooth - stacks of flattened sacs
(ii) inner membrane - with numerous - processing, packaging & distribution of
infoldings cristae that increase its proteins & lipids (like a post office) that are
surface area& consequently synthesized at one location in the cell and
enhance its ability to produce ATP used at another place
CHLOROPLAST LYSOSOMES
- site of photosynthesis - membrane -enclosed sacs, filled with
- contains chlorophyll hydrolytic enzymes
- contains DNA and ribosomes - digest or breaks down macromolecules
(intracellular digestion centers )
- energy converting organelle
- destroys worn -out cell components (like a
- double-membraned organelle
garbage disposal )
a. outer membrane
- sometimes called “suicide capsules” as the
b. inner membrane enzymes released by them kill can the cell
c. stroma - semi fluid material enclosed by NUCLEUS
the inner membrane
- storage of genetic library
d. thylakoids - interconnected, hollow, disk-
- control center of the cell
shaped flattened sacs embedded within the
stroma - storage & synthesis of DNA & RNA
ENDOPLASMIC RETICULUM - double-membraned structure usually
located in the center of the cell
- site of protein synthesis/modification
NUCLEOLUS
- distribute substances
- dense structure at the center of nucleus -
a. Rough ER
composed of DNA, RNA & protein
- covered with ribosomes
- makes ribosomes
- manufactures secretory proteins
VACUOLE
- folds, modify & transport
- large, single membrane-bound and filled
b. Smooth ER with fluid
- lacks ribosomes - means “empty space” because it has no
- lipid synthesis & hormones internal structure

RIBOSOMES
- for storage of substances (esp. toxic) - some molecules can freely pass across the
“dumping site of the cell” membrane following their concentration
gradient (high to low)
- large molecules & some ions & charged
molecules are unable to freely cross the
membrane BUT may move using channel
proteins, carrier proteins, or by vesicle
formation
- large molecules may move using channel
proteins, carrier proteins, or by vesicle
formation
Plasma Membrane: PROTEINS
a. Channel protein - has a channel allowing
substance to move through the membrane
Plasma Membrane: STRUCTURE b. Carrier protein (gated protein) -
combines with a substance & help it move
through the membrane
c. Cell recognition protein - glycoproteins
helping the body recognize when invaded
by pathogens so that the immune reaction
can occur
d. Receptor protein - have a shape which
allows certain molecules to bind to it
e. Enzymatic Proteins (transport) - combines
Fluid Mosaic Model
with a substance & help it move through
the membrane

Plasma Membrane: FUNCTIONS Movement of substance inside the cell

differ
1. It protects cell contents.
– passive (free) or active (needs energy
2. Regulates entrance & exit of molecules in
& out of the cell. Plasma Membrane: MECHANISM of
TRANSPORT
Plasma Membrane: SELECTIVE
PERMIABILITY A. Passive transport - does not require
energy as substances move across the
- only specific substances can move across
membrane down a concentration
the membrane while others cannot
gradient
 followed by pinching of the plasma
membrane
b. Endocytosis
1.Phagocytosis
▪ also known as “cell eating”
▪ occurs when substances taken in by
endocytosis is large, such as food particle
or another cell
▪ diffusion of water
across a differentially 2. Pinocytosis
permeable ▪ also known as “cell drinking”
membrane due to
concentration ▪ occurs when vesicles form around
difference liquid or very small particles

▪ osmotic pressure develops 3. Receptor-mediated

▪ form of pinocytosis that uses a receptor
protein found within coated pits on the
plasma membrane

B. Active transport
- requires energy
to transport
molecules across
the plasma
membrane and
against a
concentration The TISSUE
gradient ❑ group of cells of similar structure
▪ e.g., vesicle performing a common function
formation Tissue: CATEGORIES
B1. Vesicle formation
- molecules are too large to be transported
by carrier proteins in & out of the cell
B1. Vesicle formation
a. Exocytosis - cell release substances, a
vesicle fuses with the plasma
membrane as secretion occurs
b. Endocytosis - cells take in substances 1. Epithelial Tissue
by vesicle formation
❑ consists of tightly packed cells forming
- portion of the cell membrane a layer that:
invaginates to envelope the substance,
▪ cover body surfaces
▪ line internal organs & cavities - physical protection
▪ functions: absorption & secretion - containment

✓epithelial tissues lining intestines B. Glandular epithelium

absorb nutrients from our food - cells specialized to secrete substances
✓epithelial tissues lining airways secret such as milk, wax, perspiration, sex cells,
mucus to keep them moist or hormones

❑ may possess specialized epithelial 1A. Epithelial Tissue TYPES

cells involved in secretion & absorption: ❑ based on the number of cell layers:
cilia 1. Simple – one layer of
Ciliated cell cells

- respiratory tract
- moves fluids in sweeping motion 2. Stratified – two or more
layers of cells
microvilli
3. Pseudostratified (false-
Cells with microvilli stratified) – one layer of cells
- small intestine but appear to be stratified
because the cells vary in
- increase surface area ideal for
length
absorption
goblet cell
❑ based on cell shape in the apical surface:
- lungs & lower digestive tract
SIMPLE (1 layer)
- secrete mucus
1. Squamous
❑ other function:
– thin & flat (like
important for achieving homeostasis as it floor tiles)
borders the external & body’s internal
– exchange of materials via diffusion e.g.,
environment
air sacs of the lungs
Apical surface
2. Cuboidal
- faces the outside of an organ or inside
– cube-shaped (like a
of a tube/passageway
dice)
Basement membrane or basal lamina
– large cytoplasm for secretion & absorption
- consists of fibrous proteins & of materials e.g., thyroid gland
polysaccharides
3.Columnar
- separates from underlying tissues
– long (like bricks)
(barrier)
– large cytoplasm for
- regulates transport of materials
secretion & absorption of materials e.g.,
between epithelial & connective tissues
intestines
1. Epithelial Tissue TYPES
1B. Epithelial Tissue TYPES
A. Covering and Lining
1. Exocrine glands
- selective diffusion
- ducts going to the outside
- absorption/secretion
- mammary glands
2. Endocrine glands → Specialized loose CT
- ductless, secretes directly into the - does not have fibroblast or real matrix
bloodstream & only few fibers
- thyroid & pituitary glands - function as cushioning against damage
to body organs
2. Connective Tissue (CT)
→ adipose tissue
❑ sparse population of cells scattered in the
matrix (ground substance) - stores fat

▪ matrix (liquid/gel-like/solid) have - for protection

embedded fibers (padding),
insulation
Fibroblasts – cell that secrete protein fibers
(prevent heat
& macrophages that engulf foreign particles
loss) & energy
& cellular debris by phagocytosis
storage
❑functions:
❑ based on how loose or dense fibers are:
▪ bind structures together
2.Fibrous CT
▪ provide support & protection
– characterized by
▪ fill spaces, store fats & form blood cells dense collagenous
fibers – dense
▪ provide the source cells for muscle &
packing of fibers maximizes strength of
skeletal cells in animals that can regenerate
tissues
lost parts
– e.g., tendons (attach muscles to bones) &
2.Connective Tissue (CT) TYPES
ligaments (connects bones & joints)
❑ based on how loose or dense fibers are:
3. Specialized CT
1. Loose CT
– include several different tissues with
– most common CT specialized cells & unique matrices
–binds epithelial cells to underlying tissues – tissues could be solid or strong, fluid
or flexible
(e.g., underneath the skin) & holds organ in
place – e.g., cartilage, bones & blood
3.Specialized CT: CARTILAGE
– consists of CT
cells embedded – strong but flexible gel-like matrix
in gel-like matrix consists of collagen fibers
with loose – the matrix is secreted by
weave of fibers chondroblasts that matures into
chondrocytes (cartilage cells)
– chondrocytes lie in cavities (spaces)
1. Loose CT fiber types called lacunae
– support, absorbs shock, maintain
shape of structure
3.Specialized CT: BONE
– hard, calcified matrix with many collagen
fibers (bone not brittle)
– compact bone consists if repeating units
called osteons (structural & functional unit
of bone)
– bone cells (osteocytes) located in lacuna & The PLANT BODY
communicate with canaliculi (hair-like
❑ plants are multicellular like animals
canals)
–protects organs, stores calcium & other
minerals & fat, produces red & white blood
cells through the bone marrow
3. Specialized CT: BLOOD
– with a fluid extracellular matrix called
plasma → water, salts & dissolved oxygen

2 Broad Groups of Flowering Plants

3.Muscular Tissue
– most abundant
– consists of long cells called muscle fibers
containing contractile proteins (actin and
myosin) allowing muscle to contract The PLANT ORGANS

– for movement

A. ROOTS: Types & Functions

Types:

4. Nervous Tissue
– senses stimuli & rapidly transmits
signal from one part of the body to
another
– consists of neurons (basic unit of the
nervous system ) & neuroglia (support &
protect neurons)
– e.g., in brain & spinal cord
Summary: Animal Tissues Functions:
a. anchors a plant to the ground
b. absorbs & transports water & minerals
c. stores food (products of
photosynthesis)
A. ROOTS: Adaptations & Associations A. ROOTS: Organization
- developed adaptations & associations
to better perform their function
a. Adventitious- roots originate from
stem
b. Mycorrhizae- symbiotic fungi & root
association
- plant as carbon source
- fungi supplies minerals
c. Rood nodules
- formed on legumes
-symbiotic relationship of plant &
nitrogen-fixing microorganisms
A. ROOTS: Organization

The PLANT ORGANS: STEM

▪ function: support &
translocation
▪ develop from apical
meristem
B. STEM: Tissues Dicot : palisade & spongy
Monocot : spongy
C. LEAVES: Diversity
a. Based on blades

b. Based on leaves arrangement

B. STEM: Epidermis specialized

structures

How does water and nutrients

transported in plants?
Xylem – water
Phloem – food

Water transport (down-up)

a. Water is stored as capillary
water in soil are absorbed by
roots through root hairs.
Remember: water is cohesive,
they stick together
b. Water is carried to leaves
The PLANT ORGANS: LEAVES through xylem.
▪ function: c. As water evaporates, more
- solar energy collector water is pulled up (tension).

- main organ for photosynthesis Phloem transport (up-down-up)

a. Active transport.

C. LEAVES: Tissues
Energy

❑ ability to do work

❑ interconvertible
Energy Source
SUN → main source of energy for life on
earth
State of Energy
1. Potential energy (PE) Energy (E) in Chemical Reactions
- stored energy ❑ chemical reaction always have: -
- not moving reactants and products

- can be used to do work

- influenced by height & position
2. Kinetic energy (KE)
- energy in motion
- moving
- actively engaged in doing work Types of Chemical Reactions
Energy

❑ can be converted from 1 form to

another

Energy is Never Lost

❑ Law of Thermodynamics
→ energy is never lost, but is transferred
→ during transfer more energy Energy in Cellular Metabolism
dissipates as heat
❑ Cellular metabolism
❑First law of thermodynamics:
→ sum of chemical reactions that occur
→ energy can be transferred or in a cell
transformed but neither created nor
destroyed → reactions mediated by enzymes

❑ Biomass Pyramid –how biomass flow ❑ Cell is like a miniature factory

from one trophic level to the other → various reactions occur within
 → energy converted in many ways → captures light energy from the sun to
build complex organic molecules
❑ Energy currency of the cell
(carbohydrate) from simple inorganic
→ Adenosine Triphosphate (ATP) materials (CO2 and H2O)
Energy Currency of Cells → expressed in the general equation
below:
❑ Adenosine Triphosphate (ATP)
→ power every energy-requiring process
within the cells
→ high energy compound because of the
energy stored in the chemical bonds of Role of light
the phosphates • Sunlight - a type of energy called radiation
or electromagnetic radiation
❑ ATP functions:
• is a form of electromagnetic energy, which
→ synthesize macromolecules
travels in wave
→ pump substances across plasma
• Wavelength
membrane
• the distance between the crests of waves
→ muscle contraction or movement of
cell organelles • determines the type of electromagnetic
energy
Redox Reaction (Chemical Reaction)
• The electromagnetic spectrum
❑ Oxidation-Reduction Reaction
• the entire range of electromagnetic
→ important role in the flow of energy thru
energy, or radiation
biological systems
The Visible Light Spectrum
→ oxidation: atom/molecule
losses an electron →colors of light we can see

→ reduction: atom/molecule →includes wavelengths that drive

gains an electron photosynthesis

Photosynthetic Pigments

❑ pigments
→ organic molecule that captures energy by
Energy Transformations in Living Systems absorbing light energy from the sun

❑ 2 major processes →3 types

1. Photosynthesis : chlorophyll (green)

→ captures light energy : carotenoids (yellow or red)

2. Glucose metabolism : phycocyanins (blue or purple)

→ release of energy
Photosynthesis

❑ most important biological process

Photosynthesis
Photosynthetic Pigments GLUCOSE METABOLISM
• involves breaking down of glucose
into CO2 and H2O
• process by which energy from food is
converted into chemical energy in the
form of ATP
• reverse of the chemical reactions for
glucose synthesis by photosynthesis
• harvests chemical energy in sugars by
Site of Photosynthesis both substrate level phosphorylation
and by aerobic respiration
Chloroplasts: the sites (organelle) of
photosynthesis in plants Substrate-level Phosphorylation

- An enzyme transfers a phosphate group

from an organic substrate to ADP, forming
ATP
Two Phases of Photosynthesis CELLULAR RESPIRATION
1. Light - dependent reaction (Light Phase)
• Photo division
• Energy capturing
2.Light - independent reaction (Dark Phase)
• Synthesis division
• Energy storage
1.Light - dependent reaction (Light Phase)
- Photochemical phase or Light phase
- occur only in the presence of light
MAJOR STEPS
- take place in the thylakoids of the
1. Glycolysis
chloroplast
• a series of enzymatic reactions
- light is captured by photosystems which breaks glucose into 2
- water is split with chemical energy molecules of pyruvate
released used in synthesizing ATP & NADPH • does not depend on the
availability of oxygen
2. Light-independent Phase • proceeds exactly the same way
- Carbon Reduction Phase under both aerobic (with oxygen)
and anaerobic (without oxygen)
- takes place in the stroma
conditions
- plants utilize CO2 with ATP & NADPH from • occurs in the cytoplasm
light phase to produce glucose
SUMMARY: GLYCOLYSIS Summary Reactions: Acetyl Co-A Formation
• two major
phases
– Energy investment
phase
– Energy payoff
phase
• products per
molecule of
glucose: 2. Citric Acid Cycle or
Tricarboxylic Acid
— 2 pyruvate
(TCA) Cycle
—2 ATP (net gain) • also known as
Krebs Cycle
— 2 NADH
because it
ENERGY BALANCE FOR GLYCOLYSIS was discovered by Hans Krebs
(1937)
• products: 2 CO2 , 1 ATP, 3
NADH and 1 FADH2 per acetyl
CoA molecule
• also occurs in the matrix of the
MAJOR STEPS
mitochondria
2. Cellular Respiration
Citric Acid Cycle
• a cellular process that requires O2
and gives off • The citric acid cycle oxidizes organic fuel
CO2 derived from pyruvate.
• breaks down
• The acetyl group of acetyl CoA joins the
pyruvic acid
cycle by combining with the compound
completely to
oxaloacetate, forming citrate.
CO2 and H2O
• occurs in the mitochondria of • The next seven steps decompose the
eukaryotic cells citrate back to oxaloacetate, thus a cycle.

STAGES: CELLULAR RESPIRATION • Each cycle produces: 3 NADH+H+ , 1

FADH2 , 2 CO2 , 1 ATP
1. Acetyl CoA Formation (Oxidation of
Pyruvate)
• occurs in the matrix of the
mitochondria
• pyruvate (3-C) loses CO2 and
becomes a 2-C acetyl group
attached to a molecule of
coenzyme A (acetyl CoA)
• NAD+ is reduced to NADH as it
picks up two H atoms, one
associated with pyruvate and one
from CoA
 FERMENTATION
• breaks down glucose under
anaerobic conditions (absence of
oxygen)
• glycolysis → pyruvate → lactic acid or
ethyl alcohol and carbon dioxide
• occurs in bacteria and some
eukaryotic cells
3. Electron Transport System (ETS)
• also referred to as the respiratory — Ex. yeast and muscle cells of animals
chain
FERMENTATION: TYPES
• involves a series of enzymes
called cytochromes 1. Alcoholic Fermentation-
• occurs in the inner membrane Glucose→pyruvate→CO2 + ethanol + 2 ATP
and intermembrane 2. Lactic Acid Fermentation- Glucose→2
compartments of the pyruvate→2 lactate + 2 ATP
mitochondria

As the hydrogen molecule goes down the

respiratory chain, ATP is formed.
– NADH yields 3 ATPs
– FADH2 yields 2 ATPs
SUMMARY OF GLUCOSE METABOLISM

ALCOHOLIC FERMENTATION
• Used in wine production

ATP YIELD PER MOLECULE OF GLUCOSE

LACTIC ACID FERMENTATION

• used in the production of yoghurt,
sour cream and cheese
Lactic acid fermentation (in muscle cells)
• Occurs during strenuous activities
due to insufficient oxygen supply
• In the absence of oxygen, glucose is
broken down into lactic acid and
accumulation of this will cause
muscle pain
• In the presence of oxygen, lactic acid
is converted back into pyruvic acid in
the liver
PHOTOSYNTHESIS VS. RESPIRATION