CH.7

How many ATP and NADH molecules are produced from each molecule of glucose in the citric acid cycle only?

2 ATP, 6 NADH

Which of the following are the final by-products of glucose oxidation during aerobic cell respiration?

ATP, heat, and carbon dioxide

In addition to ATP, what are the end products of glycolysis?

NADH and pyruvate

In the equation, C6H12O6 + 6O2 → 6CO2 + 6H2O, ATP and heat would be on which side of the reaction?

The products because this is an exergonic reaction.

Bacteria that produce nitrite ( NO2- ) during anaerobic respiration would use ___ as their final electron acceptor.

NO3-

The reaction: pyruvate + CoA + NAD+ → acetyl CoA + CO2 + NADH, is catalyzed by pyruvate dehydrogenase. If an inhibitor of this enzyme was added to cells, then ___ levels in the cytoplasm would increase.

Pyruvate

In the reaction: pyruvate + CoA + NAD+ → acetyl CoA + CO2 + NADH.

Pyruvate is oxidized and NAD+ is reduced.

In the citric acid cycle, some intermediates are used in other metabolic reactions. Which of the following adaptations would need to be made by a cell in response to this?

Some oxaloacetate would need to be produced through an alternative pathway to combine with acetyl CoA.

In the citric acid cycle, malate is oxidized to form

oxaloacetate.

Cellular respiration produces the most energy in the form of ATP from which of the following?

oxidative phosphorylation

The enzyme responsible for converting pyruvate to acetyl CoA is called

pyruvate dehydrogenase.

During glycolysis, glucose is broken down into

pyruvate.

The ATP made during glycolysis is generated by

substrate-level phosphorylation.

During the cleavage stage of glycolysis, fructose-1, 6 biphosphate is broken down into

two molecules of glyceraldehyde-3-phosphate.

How many net ATP and NADH molecules are produced from one molecule of glucose during glycolysis?

2 ATP, 2 NADH

Which of the following are produced during the citric acid cycle?

ATP, NADH, and FADH2.

If an athlete is burning glucose only, what is the ratio of oxygen consumed to carbon dioxide that will be produced? C6H12O6 + 6O2 → 6CO2 + 6H2O

1:1

When acetyl-CoA containing radioactively labeled carbon atoms is fed to cells, the CO2 produced is not initially radioactive. However, molecules of citrate and oxaloacetate are radioactive. Only after some time has passed will radioactive CO2 be released. What is the best explanation for this observation?

Acetyl groups are not metabolized directly into CO2, but enter a cyclical metabolic pathway.

The conversion of pyruvate to acetyl CoA is irreversible. Predict what would happen to fatty acids as a result of this.

Fatty acids cannot be converted into carbohydrates.

In a PET scan a patient is injected with radioactively labeled glucose. Why would cancer cells take up more of the radioactive glucose than surrounding non-cancerous tissues?

Because they produce more enzymes found in glycolysis.

Which of the following statements is TRUE of both aerobic and anaerobic respiration?

Both use glycolysis to oxidize glucose to pyruvate and both produce NADH as high-energy intermediates.

Which of the following do yeast produce during fermentation?

Ethanol.

Some bacteria can use sulfur instead of oxygen as a final electron acceptor. What would they produce during anaerobic respiration?

H2S

Respiration is measured in a human. How do the concentrations of O2 and CO2 in inhaled air compare with exhaled air?

Inhaled air has more O2 and less CO2 than exhaled air.

When scientists placed ATP Synthase linked to fluorescent actin on a microscope slide and added ATP, the actin could be seen spinning. If the scientists instead added ADP what would happen?

The actin would not spin because it required ATP hydrolysis.

When scientists placed ATP Synthase linked to fluorescent actin on a microscope slide and added ATP, the actin could be seen spinning counterclockwise. If the experiment could be replicated in a cell going through oxidative phosphorylation what would happen?

The actin would spin clockwise because ATP would be produced instead of hydrolyzed.

Which of the following statements is true?

The citric acid cycle occurs in the mitochondria matrix.

How is a gradient of H+ ions formed across the inner mitochondrial membrane?

The electron transport chain uses energy from transfer of an electron donated by NADH to pump H+ across the inner mitochondrial membrane against its electrochemical gradient.

Which is an immediate effect of blocking the activity of mitochondrial ATP synthase?

The pH in the space between the mitochondrial membranes would decrease.

In a PET scan, a patient is injected with radioactively labeled glucose. Cells take up the radioactive glucose and the scanner detects levels of radioactivity in various parts of the body. This is a measure of the amount of glucose uptake. Cancer cells are often in an environment with low oxygen concentration and they take in high amounts of glucose. Why would a low oxygen environment lead to high glucose uptake?

They rely more on glycolysis which is less efficient than oxidative phosphorylation.

The reaction of ethanol fermentation is: pyruvate + NADH → ethanol + CO2 + NAD+. Why would a yeast need to perform this reaction in the absence of oxygen?

To produce NAD+ allowing glycolysis to continue.

The equation, C6H12O6 + 6O2 →6CO2 + 6H2O (ATP + Heat), describes which of the following processes?

cell respiration

In the citric acid cycle, the acetyl group is removed from acetyl CoA and attached to oxaloacetate to form

citrate.

High-energy electrons from molecules of NADH and FADH2 are transferred to a chain of proteins within the electron transport chain. What is the final protein in the electron transport chain?

cytochrome c

Where does glycolysis takes place?

cytosol

When heart muscles cells are deprived of oxygen, the heart still pumps for some time. What must the heart cells be able to do?

derive sufficient energy from fermentation

In the citric acid cycle, succinate is oxidized to form

fumarate

Which compound has the highest free energy and produces the most ATP per molecule when oxidized?

glucose

Which of the following processes will occur in the presence or absence of oxygen?

glycolysis

Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for the buildup of which molecule?

lactate

Which occurs only in anaerobic metabolism of glucose?

lactate fermentation

Where are the protein complexes associated with the electron transport chain located?

mitochondrial inner membrane

Energy released by the electron transport chain is used to pump H+ ions into which location?

mitochondrial intermembrane space