Question 1

In the chemiosmotic model,protons flow through ATP synthase.

Accepted Answer

The chemiosmotic model proposes that protons (H+) flow through ATP synthase to generate ATP. This flow of protons creates a proton gradient or electrochemical gradient, which is used to power the synthesis of ATP from ADP and Pi.

Question 2

Ammonium ions and carbon dioxide combine to produce urea in the urea cycle.

Accepted Answer

This is a true statement. The urea cycle takes place in the liver and involves the combination of ammonium ions (generated by the breakdown of amino acids) and carbon dioxide to produce urea, which is then excreted out of the body in the urine.

Question 3

The end product of glycolysis is pyruvate.

Accepted Answer

Glycolysis is a metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process. Therefore, the end product of glycolysis is pyruvate.

Question 4

A 10 carbon fatty acid goes through β-oxidation and produces 64 ATP.

Accepted Answer

The complete β-oxidation of a 10-carbon fatty acid produces 6 acetyl-CoA molecules. Each acetyl-CoA molecule can be oxidized in the citric acid cycle to produce 12 ATP molecules. Therefore, the complete β-oxidation of a 10-carbon fatty acid can produce a total of 6 × 12 = 72 ATP molecules. However, 2 ATP molecules are consumed in the activation of the fatty acid, so the net ATP yield is 72 - 2 = 64 ATP molecules.

Question 5

The citric acid cycle involves two decarboxylation reactions.

Accepted Answer

The citric acid cycle, also known as the Krebs cycle or TCA cycle, involves two decarboxylation reactions in which carbon dioxide is removed from the cycle. These reactions occur during the conversion of isocitrate to alpha-ketoglutarate and during the conversion of alpha-ketoglutarate to succinyl-CoA.

Question 6

FAD  is the oxidized form of FAD.

Accepted Answer

The answer of FAD  is the oxidized form of...

Question 7

The end product of the citric acid cycle is oxaloacetate.

Accepted Answer

Oxaloacetate is regenerated at the end of the citric acid cycle, allowing the cycle to continue by combining with acetyl-CoA to start another round.

Question 8

The urea cycle is the major pathway for eliminating the excess nitrogen from amino acid degradation in mammals.

Accepted Answer

The urea cycle is indeed the major pathway for eliminating excess nitrogen from amino acid degradation in mammals.

Question 9

The total energy obtained from the degradation of a fatty acid depends on the carbon chain length.

Accepted Answer

This is true. Fatty acids can have different lengths of carbon chains, and longer chains generally provide more energy when degraded through beta-oxidation. This is because longer chains have more carbons that can be oxidized to release energy, resulting in more ATP being produced during the process. Shorter chains, on the other hand, may be metabolized more quickly but produce less energy overall.

Question 10

A 10 carbon fatty acid goes through β-oxidation 10 times.

Accepted Answer

A 10 carbon fatty acid goes through β-oxidation 4 times, as each cycle removes a 2-carbon acetyl-CoA unit, not once per carbon.

Question 11

Each NADH that enters electron transport produces 2.5 ATP.

Accepted Answer

This is true. During electron transport, each NADH molecule transfers its electrons to the electron transport chain, generating energy that is ultimately used to produce ATP. The exact number of ATP molecules produced per NADH varies depending on the specific electron transport chain used, but the average is around 2.5 ATP per NADH.

Quiz 18: Metabolic Pathways and Energy Production