Biochem C785 EXAM 2022/2023
Cori Cycle - CORRECT ANSWERS The Cori Cycle involves the production of
lactate by anaerobic cells or cells lacking mitochondria (red blood cells), which rely on
glycolysis are their sole source of ATP. All pyruvate generated by glycolysis is
converted to lactate and then exported into the blood. Liver cells take up the lactate and
use the gluconeogenesis pathway to convert two molecule of lactate into glucose. This
glucose is then transported by the blood back to the cells that rely on glucose for ATP
production. The Cori cycle requires that the liver uses 6 ATP molecules to perform
gluconeogenesis, while glycolysis in the cells only produce 2 ATP which equals a net
loss of 4 ATP.
How many ATP are needed for gluconeogenesis to occur? - CORRECT ANSWERS
6 molecules of ATP are needed for gluconeogenesis.
How many ATP are produced by glycolysis? - CORRECT ANSWERS 2 ATP are
produced by glycolysis.
What is the net loss/gain of ATP from the Cori cycle? - CORRECT ANSWERS The
Cori cycle results in a net LOSS of 4 ATP per glucose molecule.
Glucose is a monosaccharide. It can be used as the raw material to build which one of
the following molecules?
a. Nucleic acids
b. none of these
c. Proteins
d. Glycogen - CORRECT ANSWERS d. Glycogen. Glycogen is a polysaccharide
made up of glucose units.
Glycolysis is the conversion of glucose to pyruvate. Is this a catabolic process of
anabolic process?
a. none of these
b. both of these
c. catabolic
d. anabolic - CORRECT ANSWERS c. Catabolic. Catabolic pathways refer to the
breakdown of larger molecules into smaller ones and often produce ATP as a result.
Glycolysis is a catabolic process because a molecule of glucose is broken down into
two molecules of pyruvate and two molecules of ATP.
Which of the following is an accurate statement about glycolysis?
a. glycolysis is the breakdown of a glucose molecule that requires the presence of
oxygen
b. glycolysis results in a net production of four ATP molecules
c. all of these
d. the final product of glycolysis are 2 molecules of pyruvate - CORRECT ANSWERS
d. the final product of glycolysis are 2 molecules of pyruvate.
,Biochem C785 EXAM 2022/2023
True or False. Glucose is the only food source that can make acetyl Co-A. - CORRECT
ANSWERS False
In the presence of oxygen, the end products of glycolysis have the potential to enter
which of the following pathways?
a. glycolysis
b. fermentation
c. citric acid cycle
d. none of these - CORRECT ANSWERS c. Citric acid cycle. In the presence of
oxygen, pyruvate forms acetyl co-a and enters the citric acid cycle, while fermentation
occurs in the absence of oxygen.
In human cells, glycolysis takes place in the cytoplasm. The products of glycolysis will
enter the __________ to continue with aerobic respiration.
a. mitochondria
b. cytoplasm
c. nucleus
d. ribosomes - CORRECT ANSWERS a. mitochondria.
NADH and FADH2 are two cofactors made in the citric acid cycle. They then donate the
_________ they gain in the citric acid cycle to the electron transport chain.
a. ATP
b. glucose
c. Oxygen
d. electrons - CORRECT ANSWERS d. electrons. Oxygen has a role as the
terminal electron acceptor in the electron transport chain.
During periods of strenuous exercise the muscle cells can become anaerobic. Without
oxygen, the electron transport chain cannot continue and the citric acid cycle slows
down. In such situations, how do cells make ATP?
a. there is no requirement for ATP in the muscles
b. pyruvate remains untransformed
c. pyruvate produces acetyl co-a and enters the citric acid cycle
d. pyruvate is transformed into lactate - CORRECT ANSWERS d. pyruvate is
transformed into lactate. In the absence of oxygen, pyruvate is reduced to form lactic
acid by fermentation.
The citric acid cycle produces large amounts of NADH. If NADH is already abundant in
the cell, the enzymes of the citric acid cycle that produce NADH will be inhibited by this
product and slow the cycle. - CORRECT ANSWERS Feedback inhibition
The citric acid cycle could be inhibited by a high concentration of ________ due to
feedback inhibition.
, Biochem C785 EXAM 2022/2023
a. Oxygen
b. NADH
c. Glucose
d. NAD+ - CORRECT ANSWERS b. NADH
Cyanide binds to complex IV of the electron transport chain, preventing electron
transport. Which of the following would be the most immediate effect(s) of cyanide
consumption?
Select all that apply.
a. Oxygen would not be consumed by the electron transport chain
b. Protons will not be pumped to the intermembrane space
c. ATP synthase will produce ATP
d. ATP will build up
e. ADP will build up - CORRECT ANSWERS a. Oxygen would not be consumed
by ETC
b. Protons will not be pumped to the intermembrane space
e. ADP will build up
In an exercising muscle cell under anaerobic conditions, _______ from glycolysis is
turned into ______ in order to regenerate _____ for further rounds of glycolysis, which
produces ______ ATP per round for the muscle cell to use. The Cori Cycle allows
______ to be turned into ______ via gluconeogenesis in the liver at the expense of
____ ATP. This means that, overall, the Cori cycle creates a deficit of _____ ATP.
lactate pyruvate lactate 4 6 2 glucose NAD+ - CORRECT ANSWERS In an
exercising muscle cell under anaerobic conditions, pyruvate from glycolysis is turned
into lactate in order to regenerate NAD+ for further rounds of glycolysis, which produces
2 ATP per round for the muscle cell to use. The Cori Cycle allows lactate to be turned
into glucose via gluconeogenesis in the liver at the expense of 6 ATP. This means that,
overall, the Cori cycle creates a deficit of 4 ATP.
What do low blood glucose levels stimulate? - CORRECT ANSWERS It stimulates
the secretion of glucagon from the alpha cells of the pancreatic islets.
What does glucagon act on and what does this do? - CORRECT ANSWERS
Glucagon acts on hepatocytes to accelerate the conversion of glycogen into glucose
(glycogenolysis) and promotes formation of glucose from lactic acid and certain amino
acids (gluconeogenesis).
What does increased glucagon levels promote? - CORRECT ANSWERS
Increased glucagon stimulates the hepatocytes to release glucose into the blood stream
more rapidly increasing blood glucose levels.
What do increased blood glucose levels inhibit? - CORRECT ANSWERS
Increased blood glucose levels inhibit the secretion of glucagon via feedback inhibition.
Cori Cycle - CORRECT ANSWERS The Cori Cycle involves the production of
lactate by anaerobic cells or cells lacking mitochondria (red blood cells), which rely on
glycolysis are their sole source of ATP. All pyruvate generated by glycolysis is
converted to lactate and then exported into the blood. Liver cells take up the lactate and
use the gluconeogenesis pathway to convert two molecule of lactate into glucose. This
glucose is then transported by the blood back to the cells that rely on glucose for ATP
production. The Cori cycle requires that the liver uses 6 ATP molecules to perform
gluconeogenesis, while glycolysis in the cells only produce 2 ATP which equals a net
loss of 4 ATP.
How many ATP are needed for gluconeogenesis to occur? - CORRECT ANSWERS
6 molecules of ATP are needed for gluconeogenesis.
How many ATP are produced by glycolysis? - CORRECT ANSWERS 2 ATP are
produced by glycolysis.
What is the net loss/gain of ATP from the Cori cycle? - CORRECT ANSWERS The
Cori cycle results in a net LOSS of 4 ATP per glucose molecule.
Glucose is a monosaccharide. It can be used as the raw material to build which one of
the following molecules?
a. Nucleic acids
b. none of these
c. Proteins
d. Glycogen - CORRECT ANSWERS d. Glycogen. Glycogen is a polysaccharide
made up of glucose units.
Glycolysis is the conversion of glucose to pyruvate. Is this a catabolic process of
anabolic process?
a. none of these
b. both of these
c. catabolic
d. anabolic - CORRECT ANSWERS c. Catabolic. Catabolic pathways refer to the
breakdown of larger molecules into smaller ones and often produce ATP as a result.
Glycolysis is a catabolic process because a molecule of glucose is broken down into
two molecules of pyruvate and two molecules of ATP.
Which of the following is an accurate statement about glycolysis?
a. glycolysis is the breakdown of a glucose molecule that requires the presence of
oxygen
b. glycolysis results in a net production of four ATP molecules
c. all of these
d. the final product of glycolysis are 2 molecules of pyruvate - CORRECT ANSWERS
d. the final product of glycolysis are 2 molecules of pyruvate.
,Biochem C785 EXAM 2022/2023
True or False. Glucose is the only food source that can make acetyl Co-A. - CORRECT
ANSWERS False
In the presence of oxygen, the end products of glycolysis have the potential to enter
which of the following pathways?
a. glycolysis
b. fermentation
c. citric acid cycle
d. none of these - CORRECT ANSWERS c. Citric acid cycle. In the presence of
oxygen, pyruvate forms acetyl co-a and enters the citric acid cycle, while fermentation
occurs in the absence of oxygen.
In human cells, glycolysis takes place in the cytoplasm. The products of glycolysis will
enter the __________ to continue with aerobic respiration.
a. mitochondria
b. cytoplasm
c. nucleus
d. ribosomes - CORRECT ANSWERS a. mitochondria.
NADH and FADH2 are two cofactors made in the citric acid cycle. They then donate the
_________ they gain in the citric acid cycle to the electron transport chain.
a. ATP
b. glucose
c. Oxygen
d. electrons - CORRECT ANSWERS d. electrons. Oxygen has a role as the
terminal electron acceptor in the electron transport chain.
During periods of strenuous exercise the muscle cells can become anaerobic. Without
oxygen, the electron transport chain cannot continue and the citric acid cycle slows
down. In such situations, how do cells make ATP?
a. there is no requirement for ATP in the muscles
b. pyruvate remains untransformed
c. pyruvate produces acetyl co-a and enters the citric acid cycle
d. pyruvate is transformed into lactate - CORRECT ANSWERS d. pyruvate is
transformed into lactate. In the absence of oxygen, pyruvate is reduced to form lactic
acid by fermentation.
The citric acid cycle produces large amounts of NADH. If NADH is already abundant in
the cell, the enzymes of the citric acid cycle that produce NADH will be inhibited by this
product and slow the cycle. - CORRECT ANSWERS Feedback inhibition
The citric acid cycle could be inhibited by a high concentration of ________ due to
feedback inhibition.
, Biochem C785 EXAM 2022/2023
a. Oxygen
b. NADH
c. Glucose
d. NAD+ - CORRECT ANSWERS b. NADH
Cyanide binds to complex IV of the electron transport chain, preventing electron
transport. Which of the following would be the most immediate effect(s) of cyanide
consumption?
Select all that apply.
a. Oxygen would not be consumed by the electron transport chain
b. Protons will not be pumped to the intermembrane space
c. ATP synthase will produce ATP
d. ATP will build up
e. ADP will build up - CORRECT ANSWERS a. Oxygen would not be consumed
by ETC
b. Protons will not be pumped to the intermembrane space
e. ADP will build up
In an exercising muscle cell under anaerobic conditions, _______ from glycolysis is
turned into ______ in order to regenerate _____ for further rounds of glycolysis, which
produces ______ ATP per round for the muscle cell to use. The Cori Cycle allows
______ to be turned into ______ via gluconeogenesis in the liver at the expense of
____ ATP. This means that, overall, the Cori cycle creates a deficit of _____ ATP.
lactate pyruvate lactate 4 6 2 glucose NAD+ - CORRECT ANSWERS In an
exercising muscle cell under anaerobic conditions, pyruvate from glycolysis is turned
into lactate in order to regenerate NAD+ for further rounds of glycolysis, which produces
2 ATP per round for the muscle cell to use. The Cori Cycle allows lactate to be turned
into glucose via gluconeogenesis in the liver at the expense of 6 ATP. This means that,
overall, the Cori cycle creates a deficit of 4 ATP.
What do low blood glucose levels stimulate? - CORRECT ANSWERS It stimulates
the secretion of glucagon from the alpha cells of the pancreatic islets.
What does glucagon act on and what does this do? - CORRECT ANSWERS
Glucagon acts on hepatocytes to accelerate the conversion of glycogen into glucose
(glycogenolysis) and promotes formation of glucose from lactic acid and certain amino
acids (gluconeogenesis).
What does increased glucagon levels promote? - CORRECT ANSWERS
Increased glucagon stimulates the hepatocytes to release glucose into the blood stream
more rapidly increasing blood glucose levels.
What do increased blood glucose levels inhibit? - CORRECT ANSWERS
Increased blood glucose levels inhibit the secretion of glucagon via feedback inhibition.
