Respiration: Practice Questions

In glycolysis, which takes place in the cytoplasm, what is the sequence of events involving glucose before it is converted into triose phosphate (TP)?

During the process of glycolysis, what is the net yield of ATP and the identity of the reduced coenzyme produced per molecule of glucose?

During the Krebs cycle, the conversion of a 6-carbon molecule to a 5-carbon molecule and then to a 4-carbon molecule results in the production of specific coenzymes. For every two turns of the Krebs cycle, what is the total number of reduced FAD and reduced NAD molecules produced?

In aerobic respiration, which of the following describes the correct order of molecules produced during the link reaction and the early stages of the Krebs cycle, starting from pyruvate?

In anaerobic respiration in yeast, pyruvate is converted to ethanol and carbon dioxide. Why is the production of oxidised NAD during this process essential for the cell's survival?

In the process of glycolysis, identify the specific molecule produced during the phosphorylation of glucose and state the net gain of ATP per glucose molecule.

During aerobic respiration, identify the stage that occurs in the mitochondrial matrix and produces the most reduced coenzymes per molecule of glucose.

Explain why the conversion of pyruvate to lactate in mammalian muscle cells is necessary for the continuation of glycolysis under anaerobic conditions, focusing on the recycling of coenzymes.

Aerobic respiration involves several stages that occur in different parts of the cell. A researcher is studying the metabolic activity of isolated mitochondria.

(a) Identify the specific stage of aerobic respiration that occurs in the mitochondrial matrix where acetylcoenzyme A reacts with a four-carbon molecule, and state the primary products of this stage for every one molecule of glucose. (2 points)

(b) In the final stage of aerobic respiration, oxygen acts as the terminal electron acceptor. Explain the consequences for the electron transfer chain and ATP production if oxygen is absent. (3 points)

Aerobic respiration consists of several stages including the Krebs cycle and oxidative phosphorylation.

(a) Describe the link reaction, detailing the conversion of pyruvate into acetylcoenzyme A. (2 points)
(b) According to the chemiosmotic theory, explain how the movement of protons across the inner mitochondrial membrane is coupled to the synthesis of ATP. (3 points)
(c) Explain why the total yield of ATP per molecule of glucose is significantly lower in anaerobic respiration compared to aerobic respiration. (2 points)