Photosynthesis and
Cellular Respiration
Why are oxygen bubbles a good
?
indication of photo
Oxygen is produced as a waster products
when H2O is broken down by photons. It
leaves out of the stomatas. You can see the
rate of photosynthesis by counting the
bubbles that rise in the water. More bubbles
more oxygen produced more photosynthesis.
Why is there more photosynthesis with
white than green?
Pigments in plants do not use green light.
They reflected it so with green light there is
little photosynthesis. White light is all colors
mixed together so there will be a variety of
wavelengths available for the pigments.
Why is it better that there is more
pigments than one?
When there are multiple pigments, then the
plant an absorb can use multiple
wavelengths. If they only had chlorophyll a
then thy would only absorb the extreme of
violents and reds. By having chlorophyll b
and carentoids, pigments can absorb other
blues oranges, and yellows. This allows the
plant to absorb many more wavelengths.
Why do the leaves change color in the
fall?
Chlorophyll a and b reflect green and are
the dominant pigments. In the fall, dissolve
first leaving acessory pigments such as
the carentoids which reflecy reds and
oranges. SO the leaves will lose their
green color first so that we can see the
carentoids.
Purpose of Photosynthesis
GLUCOSE!!!!!!!!!
What Do Plants Need to
Complete Photosynthesis?
 How Do the Materials Enter
the Plant?
 We must learn the different
parts of the cell that is
important first!!!!
Light Energy Harvested by Plants &
Other Photosynthetic Autotrophs
6 CO2 + 6 H2O + light energy → C6H12O6
+ 6 O2
THE BASICS OF PHOTOSYNTHESIS
• Almost all plants are photosynthetic autotrophs, as
are some bacteria and protists
– Autotrophs generate their own organic matter through
photosynthesis
– Sunlight energy is transformed to energy stored in the
form of chemical bonds
(c) Euglena
(b) Kelp
(a) Mosses, ferns, and
flowering plants
(d) Cyanobacteria
Parts of the Leaf!!!
Parts of Plant Important to
Photosynthesis



Parts of the Leaf
Mesophyll - middle layer of leaf where
chloroplast are concentrated.
Stomata - pores on bottom of leaf
where carbon dioxide enters and
oxygen leaves.
Chloroplasts: Organelles that contain
pigments which absorbs light.
What Parts do You Know?
Stomata (stoma)

Pores in a plant’s cuticle through which
water and gases are exchanged between
the plant and the atmosphere.
Oxygen
(O2)
Carbon Dioxide
(CO2)
Guard Cell
Guard Cell
Stomata
Guard Cells
open and close
depending on
vacuoles!!!!
Mesophyll Cell
Nucleus
Cell Wall
Chloroplast
Central Vacuole
Mesophyll
Chloroplast

Organelle where photosynthesis takes
place.
Stroma
Outer Membrane
Inner Membrane
Thylakoid
Granum
Chloroplasts Parts



Stroma - Thick fluid around grana
where sugars are made in Calvin
Cycle
Thylakoid - membrane sacs that
contains pigments and enzymes
Grana - Stacks of thylakoids
Occurs in the membrane of the thylakoids
Thylakoid
Thylakoid Membrane
Granum
Thylakoid Space

The location and structure of chloroplasts
Chloroplast
LEAF CROSS SECTION
MESOPHYLL CELL
LEAF
Mesophyll
CHLOROPLAST
Intermembrane space
Outer
membrane
Granum
Grana
Stroma
Inner
membrane
Stroma
Thylakoid
Thylakoid
compartment
Other Important Parts
Xylem – vessels that carry water
from roots to leaves for
photosynthesis.
 Phloem – vessels that carry
sugars from the leaves to other
parts of the plant.

WHY ARE PLANTS GREEN?
Plant Cells
have Green
Chloroplasts
The thylakoid
membrane of the
chloroplast is
impregnated with
photosynthetic
pigments (i.e.,
chlorophylls,
carotenoids).
THE SUN: WHY IS IT
IMPORTANT?
Source of light energy
Source of heat energy
Gravitational attraction
Source of radiation
Day and night
Source of all energy(electricity)
Source of food for all organisms!!!!
What part of the
spectrum do we see?
Visible light – 380 - 750
Sun’s Electromagnetic
Spectrum




The Sun’s energy travels to Earth in
waves.
Wavelength - Distance between 2 crest of
waves.
Shorter the wave the more energy it
contains.
UV waves - short waves that damage
organic tissue(cancer).
Electromagnetic Spectrum and
Visible Light
Gamma
rays
X-rays
UV
Infrared &
Microwaves
Visible light
Wavelength (nm)
Radio waves
SUN’S SPECTRUM
WHY ARE PLANTS GREEN?
Different wavelengths of visible light are seen by
the human eye as different colors.
Gamma
rays
X-rays
UV
Infrared
Visible light
Wavelength (nm)
Microwaves
Radio
waves
THE COLOR OF LIGHT SEEN IS THE
COLOR NOT ABSORBED


Chloroplasts
absorb light
energy and
convert it to
chemical energy
They absorb all
colors but green
Light
Reflected
light
Transmitted
light
Chloroplast
Absorbed
light
The feathers of male cardinals
are loaded with carotenoid
pigments. These pigments
absorb some wavelengths of
light and reflect others.
Sunlight minus absorbed
wavelengths or colors
equals the apparent color
of an object.
Why are plants green?
Transmitted light
Pigments




Pigments - light-absorbing molecules
located in the thylakoid membranes of
chloroplast.
They absorb some light and reflect the
others.
Which would we see?
Reflected!!!
Chlorophyll Molecules- IT IS A
PIGMENT!!!



Located in the thylakoid membranes.
Chlorophyll pigments harvest energy
(photons) by absorbing certain
wavelengths (blue-420 nm and red-660
nm are most important).
Plants are green because the green
wavelength is reflected, not absorbed.
Why are Chloroplast Important?
The chloroplasts absorb the Sun’s
energy and use this energy to excite
electrons which powers photosynthesis.
To break apart water and carbon
dioxide, you must have energy!!!!
Why is it important the plants
have multiple pigments

Broaden the amount of photons
collected for photosynthesis!!!
3 Types of Pigments in
Thylakoid



Chlorophyll a - Participates in light reaction
by absorbing blue-violet and red light.
Chlorophyll b - absorbs blue and orange
light.
Carenotiod - absorbs blue and reflects
reds, yellow, and orange.
Chlorophyll a - MAIN
PIGMENT

Chlorophyll a: This is the most
abundant pigment in plants and main
pigment of photosynthesis.
Chlorophyll a absorbs light with
wavelengths of 430nm(blue) and
662nm(red). It reflects green light
strongly so it appears green to us.
Accessory Pigments
THEY assist chlorophyll a by passing
photons to it!!
1. Chlorophyll b - absorbs blue and orange
light.
2. Cartenoids - absorbs blue and reflects
reds, yellow, and orange.
3. Xanthophyll: absorb blue reflect red and
yellow
Chorophyll b
This molecule has a structure similar to that
of chlorophyll a. It absorbs blue and
orange light of 453nm and 642 nm
maximally. It is not as abundant as
chlorophyll a, and probably evolved later.
It helps increase the range of light a plant
can use for energy.
2. Cartenoids - Beta Carotene

This is a class of accessory pigments that
occur in all photosynthetic organisms.
Carotenoids absorb some green light 460
nm and 550 nm and appear brown, red,
orange, or yellow to us.
3. Xanthophylls
Xanthophylls are a fourth common
class of pigments. They are usually
red and yellow and do not absorb
energy as well as cartenoids.
Why Would It Be Helpful to
Have More Than One Pigment?
If there are more than one
pigment, then it broadens the
amount of pigments that the plant
can use.
 This is why leaves can be
different colors.

Different pigments absorb light
differently
Why do the leaves change
color in winter?

Chlorophyll a and b break down
first before the carentoids. So
they reflect the oranges, reds,
and yellows!!!!
Why is Sunlight Needed for
Photosynthesis?
 It contains photons(energy)
that are trapped by
chlorophyll(pigments) from
visible light!!!!
 It absorbs the light to use as
energy. Reflected not used!!!
Energy is the ability to do
work!
Cells must have the energy to continue on
with cell processes and produce heat.
ATP – source of cell energy
Autotrophs – produce carbohydrates
Plants, algae, blue-green bacteria, and
some bacteria are autotrophs
10% of Earth’s species are autotrophs.
Heterotrophs – consumer
Fungi, animals, some bacteria and some
Photosynthesis and
Cellular Respiration
Processes involved in converting sunlight into
ATP.
Celllular respiration is conducted by ALLLL
organisms!!!!
ATP – energy
Stored in 3rd phospate
Photosynthesis is to make glucose
Photosystems



Photosystems: Clusters of proteins and
pigments that trap the Suns energy called
photons. This is where chlorophyll is
located.
Located in the thylakoid membranes.
The photosystems trap a photon and this
excited an electron to a higher level of
energy.
Photosystems
These structures are the main
structure that traps the Suns
energy so that the H2O can be
separated.
 Mixture of pigments and proteins

Photosystem
Photosystem I
and II are
proteins and
pigments to
trap the Sun’s
photons.
Located in the
thylakoid
memebrane!!!
Photosystem
Important Molecules in
Photosynthesis
NADP and ADP are energy
carriers!!
 They carry the electrons
which is energy!!!

2 Steps of
Photosynthesis
1.Light dependent reactions: Thylakoid
membranes. Pigments trap photons
H2O is split
2. Calvin Cycle: Occurs in stroma.
CO2 is used to make glucose
Overview of Photosynthesis
Step 1 – Light dependent reaction(depends on Light)
Traps the sunlight and energy is moved along
the thylakoid membrane.
Water is broken in to O and H by the electrons tha
are in ATP and NADPH required for dark
reaction.
Oxygen given off as waste.
Photosystem I and photosystem II - pigments
Step 2 – Dark reaction(Calvin Cycle - stroma
Carbon Dioxide now is added to cycle to build
glucose.Uses ATP and electrons from light reaction to
make glucose.
Describe what is happening the
diagram.
Photosynthesis







Step 1 – Light Dependent Reaction
The light reactions convert solar energy to chemical
energy. Takes place in the thylakoid membrane.
Photosystem II and electron transport
1. Pigments in photosystem II absorbs the sun’s energy to
break apart water into H, O and electrons.
2. These high energy electrons are passed along the
electron transport chain to photosystem I.
3. H+ ions are passed to ATP synthase to make ATP.
NADPH is made in photosystem I.
4. Oxygen is a waste product leaves by stomata.
Electron Transport Chain
Series of electron carrier proteins
that shuttle high energy electrons.
High - energy electrons move down
the ETC to photosystem I where it
is used to pump H ions across the
thylakoid membrane and into the
thylakoid space.
Photosynthesis
Photosystem I
1. Electrons from photosytem II is moved
along the membrane to photosystem I.
2. Electrons are added to NADPH which is
the energy carrier for the rest of
photosynthesis.
3. The H ions are pumped through a protein
channel as part of an enzyme ATP synthase to
make ATP.
Summary of Light-dependent
Reaction





* Energy is captured from sunlight and
transferred to electrons(electron transport
chain).
Water molecule pulled apart to provide H
ions.
The ions are used to make ATP and
NADPH.
Reactants: sunlight and water
Products: ATP and NADPH which will
be the energy for the Calvin Cycle!!!
Why is water needed?


Water is split to replace the electrons that
are used in the pigments. As water is
split, it replaces the electrons.
When H and split from O, it releases
electrons and O as a waste.
Plants produce O2 gas by splitting H2O

The O2 liberated by photosynthesis is made from
the oxygen in water (H+ and e-)
Why do we need high energy
electrons?


To make ATP and NADPH which are the
energy carriers.
They are needed in the Calvin Cycle to
make sugars.

Thylakoid
compartm
ent
(high H+)
The production of ATP
Lig
ht
Lig
ht
Thylakoid
membrane
Antenn
a
molecul
es
Stroma
(low H+)
ELECTRON
TRANSPORT
CHAIN
PHOTOSYSTEM
PHOTOSYSTE
II
MI
ATP
SYNTHASE
Summary—Light Dependent
Reactions
a. Reactants
light energy, H2O.
b. Products
ATP, NADPH, O2.
Light Independent Reaction Calvin Cycle
During the light - independent
reaction, ATP and NADPH
from the light dependent
reactions are used to make
high energy sugars.
Light Independent Reaction Overview
1. Carbon dioxide added:Carbon Dioxide enters the
plant from the atmosphere. Bonds with a 5-carbon sugar.
2. Three-carbon molecules formed: ATP and NADPH
use enzymes in the stroma to split the six carbon into
3 carbon sugars.
3. Three-carbon molecules exit: Most 3 carbon stay in cycle.
When 2 leave, they form glucose.
4. Three-carbon molecules recycled: Energy from ATP
Change 3carbon molecules back into 5 carbon to start the
cycle over again.
*Energy provided by Light dependent reaction.
The plants uses the carbohydrates to meet its energy needs
to make all of the macromolecules that it needs(proteins, lipi
Calvin Cycle
1. Carbon Dioxide is split and C is added to
a 5 carbon sugar by an enzyme in the
stroma of the chloroplast to make a 6
carbon sugar.
2.The 6 carbon sugar is divided into 2 by the
ATP and NADPH from LDR.
3. One three carbon will leave and others
stay in cycle.
4.After 2 cycles, glucose will be formed.
5.ATP is used to change the 3 carbon back
to 5.
Overview Calvin Cycle
Reactants: ATP, NADPH, and Carbon dioxide
Products: GLUCOSE!!
The end goal – Make glucose from the SUN!!
AN OVERVIEW OF PHOTOSYNTHESIS
• Step 2 – Light Independent Reaction – CALVIN
CYCLE Occurs in the stroma.
• The Calvin cycle makes sugar from carbon dioxide
1.ATP generated by the light reactions provides
the energy for sugar synthesis
2.The NADPH produced by the light reactions
provides the electrons for the reduction of
carbon dioxide to glucose. Carbon Dioxide is
built to make a 6 carbon sugar called glucose.
– END GOAL – to break carbon dioxide down and
combine into glucose!!! Need energy to do
this!! That is why ATP and NADPH was made!!
Factors that affect
Photosynthesis
1. Temperature: Enzymes will denature if
do not stay in 0 -35 degree range.
2. Light intensity: too little light less
photosynthesis but there is a max output
they will accomplish.
3. Water: Water is needed for
photosynthesis. No water no
photosynthesis!!!
Label Diagram Below
Explain the role pigments play
in photosynthesis.
Describe 3 factors that
would affect
photosynthesis.
Label picture below
Complete the chart below
Two Main
Processes
Reactants
Products
Location
Carbon Oxygen Cycle
The Purpose of Cellular Respiration
Break down glucose into ATP!!!!
You end up with ATP, H ions and
electrons.
The electrons are sent to the Electron
Transport Chain where they help to make
ATP through ATP synthase.
Overall Equation for Cellular Respiration
C6H12O6
+ 6O2
YIELDS
6CO2 + 6H20 + e- + 36-38ATP’s
Copyright Cmassengale
Why so Many Steps?
Energy is released slowly.
 If released all at once would be released
as heat!!!
 GOAL: TO MAKE ATP, NADH, FADH2 to
send them to the electron transport
chain. They pump H+ across
membrane(active transport). The H+
move through ATP synthase to make ATP.

Cellular Respiration
Breaking down sugars in
presence of oxygen to
make ATP!!!!
 ALL ORGANISM NEED
ENERGY
 ALL ORGANISMS DO
CELLULAR
RESPIRATION!!!

2 Types of Respiration
Glycolysis – 2 ATPS
 Anaerobic
Aerobic
 No O
O2
 1. Lactic Acid
1.Transitional
 2. Fermentation
2. Kreb Cycle

3. ETC 36 ATPS

GOAL!!!!!!
4 Stages of Aerobic Respiration
Glycolysis: before cellular respiration
Occurs in the cytoplasm
Glucose is broken down
CELLULAR RESPIRATION
1. TRANSITIONAL –pyruvate to Acetyl Co-A
2. Krebs Cycle
Breaks down pyruvate into CO2
Occurs in mitochondrial matrix
3. Electron Transport Chain
ATP is synthesized - Occurs in mito
membrane
1.
Mitochondria Structure
Smooth outer
Membrane
2. Folded inner
membrane
3.
Cristae: Folds
4. Matrix: Space
inside cristae
Copyright Cmassengale
Where Does Cellular Respiration Take
Place?

It actually takes
place in two
parts of the cell:
Glycolysis occurs
in the Cytoplasm
Krebs Cycle &
ETC Take place in
the MitochondriaCopyright Cmassengale
Net profit of ATP’s!!!
38 ATPS
– glycolysis and
cellular respiration!!
Energy Carriers in CR
*ATP
*NAD
*FAD
NADP vs. NAD
* Photosynthesis use the electron
carrier - NADP
(nicotinmide adenine dinucleotide
phosophate)
* Cellular respiration uses - NAD
( nicotinmide adenine dinucleotide)
Are There Any Other Electron Carriers?
YES! Another
Coenzyme!
 FAD+ (Flavin
adenine
dinucleotide)
 Reduced to
FADH2

Copyright Cmassengale
Diagram of the Process
Occurs
across
Cristae
Occurs in
Cytoplasm
Occurs in
Matrix
Copyright Cmassengale
Glycolysis(sugar splitting) Summary
1. Takes place in the Cytoplasm
2. Anaerobic (Doesn’t Use Oxygen)
3. Requires input of 2 ATP
4. Glucose split into two molecules
of Pyruvate or Pyruvic Acid
Copyright Cmassengale
Glycolysis
Glyco = glucose
Lysis = break down
 LOCATION: Occurs in the cytoplasm
 This stage occurs in BOTH aerobic
and anaerobic respiration
 Glucose breaks down into 2 pyruvate (2
ATP are also made)

◦ Glucose is a 6-carbon sugar
◦ Pyruvate is a 3-carbon molecule (there are
two of them)
Steps of Glycolysis
1.Two ATP molecules are used to energize
a glucose molecule.
2. Glucose is split into 2 - 3 carbon
molecules. Enzymes rearrange the
molecules.
3. Electrons are transferred to NADP. The
carbon molecules are converted to pyurate
which enters cellular respiration.
Glycolysis:
Step 1
Glucose
Figure 9–3 Glycolysis
2 Pyruvic acid
To the electron
transport chain
Glycolysis Reactants and Products
Reactants
 1 glucose
 Enzymes are
needed
 2 ATP are needed
to start
Products
 2 Pyruvates (go to
next step)
 4 ATP (2 are gained)
 2 NADH (go to ETC)
Really 10 steps with 10 different enzymes
involved.
TRANSITION REACTION
Pyuvic Acid is shuttled into the
mitochondria matrix where it is
changes into Acetyl Co A.
Acetyl CoA – this is the molecule that
is used in Kreb Cycle!!!
Cellular Respiration Overview
After glycolysis, life diverges into two forms
and two pathways
1. Anaerobic cellular respiration (aka
fermentation) No oxygen
2. Aerobic cellular respiration I Oxygen
needed!!
ANAEROBIC VS. AEROBIC
Anaerobic – no oxygen present
fermentation or lactic acid can be
formed. No oxygen then no cellular
respiration.
Aerobic –oxygen present. If oxygen is
present , then cellular respiration can
occur.
Aerobic vs. Anaerobic
Anaerobic DOES NOT
require oxygen fermentation

◦ Simple
◦ fast
◦ produces smaller
amounts of energy
(ATP)

Aerobic requires
oxygen – cellular
respiration
◦ Yields large
amounts of
energy
◦ What is this
energy molecule?
 ATP, ATP, ATP
Krebs Cycle Reactants and Products
Reactants
 2 Acetyl CoA
 NADH
 FADH

Remember when you form
a bond energy is released!!
This is the key!!
Products
2 ATP
 6 NADH (go to ETC)
 2 FADH2 (go to ETC)
 4 CO2 (given off as
waste)

 END
GOAL – Make
NADH and FADH

NADH and FADH is carried
to the elestron transport chain
to make ATP. THE END OF
GOAL!!!
Main Goals of Krebs Cycle or Citric
Acid Cycle
 Transfer
high energy
electrons(NADH and FADH) to
molecules that can carry them to
the electron transport chain to
make 34 ATPS.
Krebs Cycle Summary
A.
Requires Oxygen (Aerobic)
B. Cycle series of oxidation(uses)
reactions that give off CO2 and
produce one ATP per cycle
C.Turns twice per glucose molecule
produces two ATP
D. Location: matrix of mitochondria
Copyright Cmassengale
Section 9-2
Citric Acid
Production
Kreb Cycle
1. Coenzyme A enter the cycle and bonds
to 4 carbon molecule
2. Citric Acid formed which is a 6 carbon.
3. Citric Acid broken down: into 5 carbon
sugar carbon dioxide and NADH
4. 5 carbon sugar broken down: Into 4
carbon sugar, NADH, ATP and Carbon
dioxide.
5. 4 carbon rearranged by enzymes.
Molecules of NADH, FADH are formed
to be carried down ETC.
6. 4 carbon molecule is recycled.
Products of Kreb Cycle
High energy carriers – NADH and FADH
– This is the main goal!!!
 HYDROGEN IONS ARE SENT DOWN
THE ELECTRON TRANSPORT CHAIN
to make ATP.

A Little Krebs Cycle History



Copyright Cmassengale
Discovered by Hans
Krebs in 1937
He received the Nobel
Prize in physiology or
medicine in 1953 for
his discovery
Forced to leave
Germany prior to
WWII because he was
Jewish
Krebs Cycle
ATP synthesis
Electron Transport
Electron Transport Chain Summary
34 ATP Produced
 H2O Produced
 Occurs Across Inner Mitochondrial
membrane - Cristae
 Uses coenzymes NAD+ and FAD+ to
accept e- from glucose
 NADH = 3 ATP’s
 FADH2 = 2 ATP’s

Copyright Cmassengale
GOAL OF ETC

Remove the H from energy carriers and
pump them across membrane for
diffusion through ATP synthase to make
ATP.
Make 34 ATP form one glucose!!! In ETC
 2 in Kreb Cycle
 2 in Glycolysis =ATPS total
 38 ATPS

Electron Transport Chain
 Where
inner membrane of
mitochondria called cristea.
 Energy Yield Total of 32 ATP
 O2 combines with TWO H+ to form
H2O
 Exhale - CO2, H2O comes from
cellular respiration
Electron Transport - Step 3
1. Proteins inside the membrane of the
mito. Remove electrons from NADPh and
FADH.
2. Electrons(hydrogen) are transported
down the chain of the membrane to be
pumped across.
3. ATP synthase(enzyme) puts a P on ADP
to make ATP(END GOAL!!).
4. Oxygen enters the cycle to pick up
electrons and hydrogen ions to make
water that leaves the cycle.
Electron Transport Chain
Section 9-2
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
Electron Transport Chain
Electron carriers loaded with electrons
and protons from the Kreb’s cycle move
to this chain-like a series of steps
(staircase).
 As electrons drop down stairs, energy
released to form a total of 32 ATP –
Final Goal!!
 Oxygen waits at bottom of staircase,
picks up electrons and protons and in
doing so becomes water

Electron Transport Chain

Occurs in the cristae of the mitochondria
Review of Mitochondria
Structure
Smooth outer
Membrane
l Folded inner
membrane
l Folds called
Cristae
l Space inside
cristae called the
Matrix
l
Copyright Cmassengale
Diagram of the Process
Occurs
across
Cristae
Occurs in
Cytoplasm
Occurs in
Matrix
Copyright Cmassengale
Energy Tally

36 ATP for aerobic vs. 2 ATP for anaerobic
◦ Glycolysis
2 ATP
◦ Kreb’s
2 ATP
◦ Electron Transport
32 ATP
36 ATP

Anaerobic organisms can’t be too
energetic but are important for global
recycling of carbon
Photosynthesis
What happens to the glucose formed in photosynthesis?
PHOTOSYNTHESIS
CELLULOSE
LIPIDS
GLUCOSE
respiration
ATP
Required to make plant cell walls. It is made
of 100s of glucose molecules bonded
together.
Glucose is chemically converted to fatty acids and
glycerol to make lipids, which are needed to make
plant cell membranes and seed storage oils.
STARCH
Is used by roots and leaves to store excess
glucose in an osmotically inactive form. It is
made of 100s of glucose molecules.
PROTEINS
Using nitrate ions absorbed by plant roots,
glucose is converted first to amino acids
then to protein.
CARBON
DIOXIDE AND
WATER
The carbon dioxide can be used again in
photosynthesis or may diffuse out of the
leaf via the stomata
Anaerobic Cellular Respiration

When you exercise, you muscle to run out of oxygen to
and produce lactic acid!!

Some organisms thrive in environments with little or no
oxygen
◦ Marshes, bogs, gut of animals, sewage treatment ponds

No oxygen used= ‘an’aerobic

What do they cells do withoutoxygen???
Cellular Respiration Overview
After glycolysis, life diverges into two forms
and two pathways
1. Anaerobic cellular respiration (aka
fermentation) No oxygen
2. Aerobic cellular respiration I Oxygen
needed!!
Aerobic vs. Anaerobic
Anaerobic DOES NOT
require oxygen fermentation

◦ Simple
◦ fast
◦ produces smaller amounts
of energy (ATP)

Aerobic requires
oxygen – cellular
respiration
◦ Yields large
amounts of energy
◦ What is this energy
molecule?
 ATP, ATP, ATP
Fermentation

In absence of oxygen, fermentation
releases energy from food molecules by
producing ATP.

Very small amounts of ATP!!!
Fermentation
Glycolysis occurs to produce ATP and
NADH!! Normal
Glucose is broken down into pyruvic acid
to make ATP and NADH.
This is the only ATP made.
Two Types of Fermentation
Alcoholic Fermentation
 Pyruvate converted to ethyl
alcohol and CO2
 Carried out by yeast and
some bacteria
 Used in producing alcohol
(both consumable and for
ethanol), and for baking
Lactic Acid Fermentation
 Pyruvate converted to lactic
acid
 Carried out by muscles
when working hard
(muscles need ATP but
can’t get O2 )
 Causes muscle soreness and
cramps
Alcohol Fermentation

Pyruvate
Fermentation
 Occurs when O2 NOT present
(anaerobic)
Called Lactic Acid fermentation in
muscle cells (makes muscles tired)
Called Alcoholic fermentation in
yeast (produces ethanol)
Nets only 2 ATP
Copyright Cmassengale
Importance of Fermentation
Alcohol Industry - almost every society
has a fermented beverage.
 Baking Industry - many breads use yeast
to provide bubbles to raise the dough.

Alcoholic Fermentation

Bacteria and fungi (yeast)

Ethyl alcohol and carbon dioxide
are the end products
Process used to form beer, wine,
and other alcoholic beverages
 Also used to raise dough, bread

Lactic Acid Fermentation
Uses only Glycolysis.
 Does NOT require O2
 Produces ATP when O2 is not
available.

Lactic Acid Fermentation
Carried out by human muscle cells under
oxygen debt.
 Lactic Acid is a toxin and causes fatigue,
soreness and stiffness in muscles.

Lactic Acid Formation

pyruvate + NADH----- lactic acid +
NAD+
Lactic Acid Fermentation
Glycolysis
4 ATP’s are
produced
Pyruvic Acid (3C)
Lactic Acid (3C)
Pyruvic Acid (3C)
Lactic Acid (3C)
Glucose
(6 carbons)
2 ATP’s supply
the activation
energy
2 NAD+ + 2 e-
2 NADH
2 NAD+ + 2 e-
4 ATP Yield = 2 ATP Net Gain
Fermentation - Summary
Releases 2 ATP from the breakdown of
a glucose molecule
 Provides ATP to a cell even when O2 is
absent.
