1. CHAPTER 9
CELLULAR RESPIRATION

2. CHAPTER 9: CELLULAR RESPIRATION
9-1 Chermical Pathways
A. Chemical Energy and Food
Food serves as a source for _________.
1g of glucose (C6H12O6) releases _______ calories.
calorie=
We gradually release the energy of glucose and other
compounds (fats, proteins, and carbohydrates).
The process begins with a pathway called__________.
If oxygen is present,
If oxygen is not present,
energy
3,811
the amount of energy needed to raise the temperature of 1g of water 1°C.
glycolysis.
glycolysis leads to cellular respiration (Krebs cycle and electron transport chain). (process = aerobic)
glycolysis leads to fermentation. (process = anaerobic)

3. Fermentation (without oxygen)
Section 9-1
Chemical Pathways
Glucose
Glycolysis
Krebs cycle
Electron transport
Alcohol or
2. Lactic acid
Fermentation (without oxygen)

4. B. Overview of Cellular Respiration
Remember: the ____________ is the
organelle known as the “powerhouse”- the site
where energy is produced.
Cellular respiration takes place in the mitochondria.
The equation for cellular respiration=
the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.
mitochondria
6O2 + C6H12O6
6CO2 + 6H20 + Energy

5. ________ stores large amounts of energy. The
cell can’t release all the energy at one time. It is too
much for the cell to handle.
3 main stages of cellular respiration: 1. 2. 3.
Glucose
Glycolysis (glycol= sugar; lysis=break apart)
Krebs Cycle
Electron Transport Chain (ETC)

6. Electron Transport Chain
Flowchart
Section 9-2
Cellular Respiration
Glucose (C6H1206) +
Oxygen (02)
Glycolysis
Krebs Cycle
Electron Transport Chain
Carbon
Dioxide
(CO2) +
Water
(H2O)

7. Respiration: An Overview
Section 9-1
Mitochondrion
Electrons carried in NADH
Electrons carried in NADH and FADH2
Pyruvic acid
Glucose
Electron Transport Chain
Krebs Cycle
Glycolysis
Mitochondrion
Cytoplasm 2 2 34

8. To the electron transport chain
C. Glycolysis=
the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound.
This pathway does
not require oxygen
Prokaryotes depend on this process alone for ATP.
Section 9-1
Glucose
2 Pyruvic acid
PGAL
(Phosphoglyceraldehyde)
To the electron transport chain

9. 1. ATP Production
Use__ ATP
Makes __ ATP
Net gain is __ ATP
NADH Production
NAD+ (nicotinamide adenine dinucleotide) is an _____________.
NAD+ accepts electrons to make ______ (an electron carrier).
In glycolysis, ________ are produced.
NADH will carry its’ electrons to 2 4 2
Electron carrier
NADH
2 NADH
the electron transport chain.

10. 3. Overall, Glycolysis produces
2 ATP “Net” (energy molecules)
2 NADH (electron carriers)
2 Pyruvic Acid (3-C sugars)

11. 9-1 [continued...] Fermentation
What happens when oxygen is not present?
Fermentation=
The pyruvic acid can go through one of two types of
fermentation:
1. __________ Fermentation
Occurs in
Pyruvic acid + NADH →
Important to
____ released causes bread to rise
Anaerobic process
release of energy from food molecules by producing ATP
in the absence of oxygen.
Glycolysis still occurs in the cytoplasm producing pyruvic acid.
Alcoholic
yeast cells and other microorganisms.
alcohol + CO2 + NAD+
bakers and brewers.
CO2 11

12. 2. ___________ Fermention Lactic Acid
Section 9-1
Glucose
Pyruvic acid
Lactic acid
Produced in our
Build up of _________ causes the
______ is
Prokaryotes are used to make food because they do
produce lactic acid. Some examples:
-cheese -kimchi -sour cream
-yogurt -sauerkraut -buttermilk -pickles
muscle cells when oxygen levels are too low
Lactic Acid
burning feeling.
NAD+
regenerated to keep running glycolysis. 12

13. Fermentation (without oxygen)
Section 9-1
Chemical Pathways
Glucose
Krebs cycle
Electron transport
Glycolysis
Alcohol or lactic acid
Fermentation (without oxygen) 13

14. COMPARISON OF FERMENTATION TO CELLULAR REPIRATION
Lactic Acid
Alcoholic
Cellular respiration
glucose
glucose
glucose
glycolysis (pyruvic acid)
glycolysis (pyruvic acid)
glycolysis (pyruvic acid)
carbon dioxide
carbon dioxide
lactic acid
alcohol
water
2 ATP
2 ATP
38 ATP (net 34) 14

15. 9-2 The Krebs Cycle and Electron Transport
A. The Krebs Cycle (aka: Citric Acid Cycle)
1. Pyruvate (pyruvic acid) oxidation
2. Energy Extraction

16. Named after __________.
Occurs in the Mitochondria (therefore this process only
occurs in __________)
Krebs cycle=
Krebs cycle begins
Hans Krebs
Eukaryotes
process where pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.
when pyruvic acid enters mitochondria.

17. 1. Pyruvate (pyruvic acid) Oxidation
In this process, it produces the following for glucose: -
2 acetyl-CoA (2-C sugar)
2 NADH (electron carriers)
2 Carbon dioxide (waste product)

18. 2. Energy Extraction

19. Acetyl CoA ( ) binds with a Oxaloacetic acid
( ) molecule to form Citric Acid ( )...Hence,
the name Citric Acid Cycle.
Citric Acid is oxidized (by NAD+ and FAD) through a
series of reactions that finally produces Oxaloacetic Acid
again.
The Krebs Cycle runs __ times per Glucose
molecule. (Once per pyruvic acid.)
This process produces (per glucose molecule):
- ___ NADH (electron carriers-go to ETC)
- ___ FADH2 (electron carriers-go to ETC)
- ___ ATP (energy-used by cell to do work)
- ___ CO2 (waste product- gets exhaled)
2-C
4-C
6-C 2 6 2 2 4

20. B. Electron Transport (ETC) The Electron Transport Chain=
process that uses the high-energy electrons from the Krebs cycle to convert ADP into ATP.
Section 9-2
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production

21. The Process:
Electron Transport
1. Glycolysis and the Krebs Cycle deliver their
________ and _______ to the matrix of the
mitochondria.
2. NADH and FADH2 donate their high energy electrons
to the ETC.
NADH → NAD
FADH2→ FAD
(recycled) (go to intermembrane space) (passed to ETC)
NADH
FADH2 H+ e-
2H+
2e-

22. 3. Electrons are passed from carrier to carrier in the
inner membrane.
*(in prokaryotes )
4. At the end of the chain, ________ is the
5. Oxygen uses the electron to
the ETC is in the cell membrane
Oxygen
final electron acceptor.
covalently bond with hydrogen forming
water. (oxygen is reduced)
Interactive link: Use ETS and Making ATP

23. B. Hydrogen Ion Movement
1. As the high energy electrons are transported down the
chain,
2. It takes
3. The _____________ space becomes (+) positively
charged.
4. The _______ becomes (-) negatively charged.
their energy is used to push H+ from the matrix,
through the inner membrane, to the
intermembrane space.
2e- to move 1H+
intermembrane
matrix

24. C. ATP Production
1. Hydrogen ions return to the matrix through the enzyme
2. As Hydrogen passes, the enzyme
D. This process produces: -
ATP synthase.
grabs a phosphate and attaches it to ADP to become ATP.
34 ATP
water

25. C. The Totals Per Glucose molecule ***note: each NADH produces __ ATP
each FADH2 produces __ ATP 3 2
Click on ATP synthesis and play the first one only
LOCATION
ATP
NADH
FADH2
BYPRODUCTS
GLYCOLYSIS
KREBS CYCLE:
Pyruvate oxidation →
Energy Extraction →
ELECTRON TRANSPORT CHAIN
TOTALS (net)
cytoplasm 2 2
------
Carbon
dioxide
matrix 2
Carbon
dioxide
matrix 2 6 2
Inner
Membrane
(Cristae) 34
water 36 10 2
-2 ATP (transport of pyruvic acid into mitochondria)

26. D. Energy and Exercise (refer to activity sheet)
E. Comparing Photosynthesis and Cellular Respiration
Photosynthesis
Cellular Respiration
Function
Location
Reactants
Products
Equation
Energy Release
Energy Capture
Chloroplasts
Mitochondria
H2O and CO2
C6H12O6 and O2
C6H12O6 and O2
H2O and CO2
6H2O + 6CO2 → C6H12O6 + 6O2
C6H12O6 + 6O2 → 6H2O + 6CO2

27. Section 9.3 Summary – pages 231-237
Comparing Photosynthesis and Cellular Respiration
Photosynthesis
Cellular Respiration
Food synthesized
Food broken down
Energy from sun stored in glucose
Energy of glucose released
Carbon dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Produces sugars from PGAL
Produces CO2 and H2O
Requires light
Does not require light
Occurs only in presence of chlorophyll
Occurs in all living cells
Section 9.3 Summary – pages

28. California State Standards
1g. Students know the role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide.
1i* Students know how chemiosmotic gradients in the mitochondria and chloroplasts store energy for ATP production.

29. Warm-up Section 9-1 What is cellular respiration?
Draw a picture of a cell and label where glycolysis, krebs cycle, and ETC occur.
What happens during the process of glycolysis?

30. Warm up section 9-2 What happens during the Krebs cycle.
How are high energy electrons used by the electron transport chain?
What pathways are taken by pyruvic acid if oxygen is not available?

31. Cytoplasm If oxygen is not present: Fermentation If oxygen is present:
Pyruvic
acid
Lactic acid
(or Alcohol
& CO2 )
If oxygen is present:
Cellular Respiration
PGAL
Pyruvic
acid
To ETC
Cytoplasm