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BIOL 161 Cellular Respiration
Chpt 8, Biology, 9th ed
8.1 Cellular respiration
I.
Introduction
A. Consider the following equation for the breakdown of glucose in the presence of oxygen:
C6H12O6 + 6 O2 → 6 H2O + 6 CO2
1. Is the above reaction an exergonic or an endergonic reaction?
2. Is glucose (oxidized or reduced) to form what compound?
3. Is oxygen (oxidized or reduced) to form what compound?
B. Complete the following dehydration reaction for the formation of ATP:
PO4 + __________ → _________ + water
1. Is the above reaction an exergonic or an endergonic reaction?
C. As a result, can the breakdown of glucose be coupled with the formation of ATP?
D. Generally, how many ATP molecules may form when one glucose molecule breaks
down?
II.
NAD+ and FAD
A. Complete the following reaction for the reduction of NAD+.
NAD+ + 2 e- + H+ → __________
B. Complete the following reaction for the reduction of FAD.
FAD + 2 e- + 2 H+ → __________
III.
Phases of Cellular Respiration (a broad overview)
A. Glycolysis
1. Where does glycolysis take place in a eukaryotic cell?
2. Does glycolysis require oxygen?
3. When glucose breaks down, how many molecules of pyruvate are made?
4. Do any NADH form?
5. Do any ATP form?
B. Prep reaction
1. Where does prep reaction take place in a eukaryotic cell?
2. Pyruvate made in glycolysis becomes (oxidized or reduced?) during prep reaction.
3. A 2-carbon group is formed. This 2-carbon group is called __________ and will be
attached to CoA.
4. Do any NADH form?
5. What gas is released during this reaction?
C. Citric acid cycle
1. Where does citric acid cycle take place in a eukaryotic cell?
2. Acetyl CoA made during prep reaction enters the citric acid cycle where several
intermediates are (oxidized or reduced?).
3. Do any NADH form?
4. Do any FADH2 form?
5. Do any ATP form?
D. Electron transport chain (and then chemiosmosis)
8.2 Outside the Mitochondria: Glycolysis
I.
Introduction
A. Where does glycolysis take place in a eukaryotic cell?
B. Does glycolysis require oxygen?
C. When glucose breaks down, how many molecules of pyruvate are made?
II.
Energy-Investment Steps
A. How many carbon atoms are in one glucose molecule?
B. Before glucose can do anything, it needs to be activated by how many molecules of ATP?
C. After glucose activation by ATP, glucose splits into two molecules of a 3-carbon
compound called __________, which finishes glycolysis.
III.
Energy-Harvesting Steps
A. When each of the G3P is oxidized, its electrons and hydrogen ions reduce NAD+ to form
a total of ______ NADH molecules.
B. How many molecules of ATP are made by substrate-level phosphorylation during
glycolysis? This means that an enzyme allows a phosphate from a substrate to be
transferred to ADP so that ATP can form.
C. If you substract the ATP needed to get things started from the amount of ATP made
during substrate-level phosphorylation, what is the NET gain of ATP?
D. When oxygen is available, what happens to the pyruvate, the end product?
E. How many carbon atoms are in one molecule of pyruvate?
F. Because hydrogen atoms and electrons are being removed continually from glucose, is
glucose being oxidized or reduced during glycolysis?
G. Fill in the table below with the above information on glycolysis.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Where
occurs in
cell
CO2 made
All numbers are from ONE glucose molecule
Net ATP
from
substratelevel
NADH
from
reaction
FADH2
from
reaction
Total ATP
for
reaction
phosphoryla
tion
Glycolysis
8.3 Inside the Mitochondria
I.
Introduction
A. How many membranes make up one mitochondrion?
B. Name the space between the outer and inner membrane.
C. Name the folds of the inner membrane that jut into the matrix.
D. Within the mitochondrion, where do preparatory reaction and citric acid cycle occur?
E. Where does the electron transport chain occur?
II.
Preparatory reaction (=transition reaction = pyruvate oxidation)
A. Where does prep reaction take place in a eukaryotic cell?
B. The two pyruvate molecules formed from glycolysis will lose one carbon each in the
form of a gas. What is the name of this gas?
C. How many molecules of CO2 are made in prep reaction per one glucose molecule?
D. Therefore, after losing a carbon atom, the acetyl group that is left has how many carbon
atoms?
E. The acetyl group is joined temporarily with a coenzyme called __________.
F. How many molecules of NADH are made in prep reaction per one glucose molecule?
G. Because electrons are being removed during prep reaction, are the two pyruvate
molecules being oxidized or reduced during prep reaction?
H. Fill in the table below with the above information on prep reaction.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Where
occurs in
cell
CO2 made
All numbers are from ONE glucose molecule
Net ATP
from
substratelevel
NADH
from
reaction
FADH2
from
reaction
Total ATP
for
reaction
phosphoryla
tion
Prep rxn
III.
Citric acid cycle (= Krebs cycle)
A. Where does citric acid cycle take place in a eukaryotic cell?
B. Each of the two acetyl groups from the prep reaction joins with a 4-carbon compound
called oxaloacetic acid (=oxaloacetate). As a result, citric acid is formed. How many
carbon atoms does citric acid have?
C. Throughout citric acid cycle, the substrate intermediates lose electrons, which reduce
coenzymes. As a result, are the substrate intermediates oxidized or reduced?
D. How many molecules of carbon dioxide (CO2) are made during citric cycle per one
glucose molecule?
E. How many molecules of ATP are made by substrate-level phosphorylation in citric acid
cycle per one glucose molecule?
F. How many molecules of NADH are made in citric acid cycle per one glucose molecule?
G. How many molecules of FADH2 are made in citric acid cycle per one glucose molecule?
H. Fill in the table below with the above information on citric acid cycle.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Where
occurs in
cell
CO2 made
All numbers are from ONE glucose molecule
Net ATP
from
substratelevel
NADH
from
reaction
FADH2
from
reaction
Total ATP
for
reaction
phosphoryla
tion
Citric acid
IV.
Electron transport chain
A. Where are the electron transport chain proteins located in a eukaryotic cell?
B. What coenzymes made during glycolysis, prep reaction, and citric acid cycle bring
electrons to the electron transport chain?
C. If NADH or FADH2 gives an electron to the first protein of the electron transport chain, is
the NADH or FADH2 oxidized or reduced? Is the protein oxidized or reduced?
D. Will the first protein then pass electrons to the next protein in the electron transport
chain?
E. Many of the carriers in the electron transport chain are cytochromes. Name the common
poison that is an inhibitor of cytochrome c oxidase.
F. As electrons are passed along the electron transport chain, energy generated from the
movement of electrons is used to make ATP. The process by which ATP is generated
using electron transport chain energy is called __________ __________.
G. Which molecule receives electrons from the last carrier in the chain? [In other words,
which molecule is the last electron acceptor?] To form which molecule?
H. When NADH delivers electrons to the electron transport chain, enough energy is
generated to produce ____ ATP molecules. Figure 8.7 is a good visual of this number as
well.
I. When FADH2 delivers electrons to the electron transport chain, enough energy is
generated to produce ____ ATP molecules. Figure 8.7 is a good visual of this number as
well.
J. Cristae of a Mitochondrion
1. Where are the protein carriers of the electron transport chain located?
2. As electrons are passed along the electron transport chain, the energy generated
pumps hydrogen ions from the ____________ to the ___________________ of a
mitochondrion so that an electrochemical gradient of H+ is established.
K. ATP Production
1. Because there are more hydrogen ions in the intermembrane space, the hydrogen ions
will diffuse back to the ________ through a protein called ________ __________.
2. As hydrogen ions flow down their gradient through ATP synthase, ADP joins with an
inorganic phosphate to form _________. This molecule has been the reason cellular
respiration occurs!!!!! The production of ATP when hydrogen ions move down their
gradient is called __________.
3. If a poison prevents an electrochemical gradient of H+ from occurring, what happens
to ATP production?
V.
Energy Yield from Glucose Metabolism
A. From substrate-level phosphorylation
1. How many ATP molecules formed from substrate-level phosphorylation during
glycolysis?
2. How many ATP molecules formed from substrate-level phosphorylation during citric
acid cycle?
B. Oxidative phosphorylation means that ATP is produced from the combination of electron
transport chain and chemiosmosis, and that oxygen is the final electron acceptor.
1. For each NADH made in the matrix that delivers electrons to the electron transport
chain, how many molecules of ATP will be produced by oxidative phosphorylation?
2. For each FADH2 that delivers electrons to the electron transport chain, how many
molecules of ATP will be produced by oxidative phosphorylation?
3. For each NADH is made in the cytosol that delivers electrons to the electron transport
chain via FAD in the inner membrane, how many molecules of ATP will be produced
by oxidative phosphorylation?
4. Fill in the table below, combining your understanding of cellular respiration.
OVERVIEW LOOK at CELLULAR RESPIRATION
C6H12O6
NADH, FADH2
pyruvate
acetyl-CoA
citric acid cycle
pyruvate
acetyl-CoA
citric acid cycle
electron transport chain, chemiosmosis, ATP made
Use the table below to fill in ATP count for a “typical” cell.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Where
occurs in
cell
CO2 made
All numbers are from ONE glucose molecule
Net ATP
from
substratelevel
NADH
from
reaction
ATP from
NADH in
oxidative
FADH2
from
reaction
phosphoryla
tion
phosphoryla
tion
ATP from
FADH2 in
oxidative
Total ATP
for
reaction
phosphoryla
tion
Glycolysis
Prep
Reaction
Citric acid
cycle
5. In a heart or liver cell, for each NADH is made in the cytosol that delivers electrons
to the electron transport chain, three molecules of ATP, instead of two, will be
produced by oxidative phosphorylation. Fill in the table below with ATP totals for a
heart or liver cell.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Where
occurs in
cell
CO2 made
All numbers are from ONE glucose molecule
Net ATP
from
substratelevel
phosphoryla
tion
Glycolysis
Prep
Reaction
Citric acid
cycle
NADH
from
reaction
ATP from
NADH in
oxidative
phosphoryla
tion
FADH2
from
reaction
ATP from
FADH2 in
oxidative
phosphoryla
tion
Total ATP
for
reaction
8.4 Fermentation
I.
Introduction
A. Does fermentation require oxygen?
B. In human bodies, if oxygen levels are low, the pyruvate made in glycolysis will be
reduced to form what compound?
C. What molecule was oxidized and contributed the hydrogen atoms to reduce pyruvate?
D. Where would fermentation occur within a eukaryotic cell? [Hint: fermentation is only
one step beyond glycolysis.]
E. In an organisms like yeast that is used in the wine industry, what is the end product of
their fermentation?
II.
Advantages and Disadvantages
A. How many ATP’s are made by substrate-level phosphorylation?
B. Are any ATP’s made by oxidative phosphorylation?
C. When we have enough oxygen, which organ converts the lactic acid back into pyruvate?
8.5 Metabolic Pool
I.
Introduction
A. Would catabolism reactions break down molecules or build molecules?
B. Would catabolism reactions be exergonic or endergonic?
C. Would anabolism reactions break down molecules or build molecules?
D. Would anabolism reactions be exergonic or endergonic?
II.
Catabolism
A. Complete the following catabolism (hydrolysis) reaction for breaking down one fat
molecule:
Fat + __________ → __________ + 3 fatty acids
B. Glycerol can be converted to glyceraldehyde-3-phosphate (G3P), which is a substrate
in__________ of cellular respiration.
C. Fatty acids are converted to __________.
D. Complete the following catabolism (hydrolysis) reaction for breaking down a protein
molecule:
Protein + __________ → many __________ __________
E. What is the process called that removes the amino group from an amino acid?
F. How can the remaining portions of the amino acid enter cellular respiration?
III.
Anabolism
A. Can eating too much carbohydrate lead to production of fat?
B. If an amino group is added to a substrate in the citric acid cycle, will your body make an
amino acid?
C. Can your body make ALL 20 amino acids?