Chapter 13 Self-test questions

. Which of the following statements about the reactions of glycolysis is correct?

In glycolysis glucose-6-phosphate is split into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

In glycolysis fructose-1,6-bisphosphate is split into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

In glycolysis fructose-6-phosphate is split into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.

In glycolysis glucose-6-phosphate is isomerized to fructose-1:6-bisphosphate.

. Which of the following statements about the glycolytic intermediate, fructose-6-phosphate is correct?

In glycolysis fructose-6-phosphate is formed from glucose-6-phosphate and is split by the aldol reaction into an aldehyde and a ketone.

In glycolysis fructose-6-phosphate is an aldol so once phosphorylated to fructose-1:6-bisphosphate cannot be split by the aldol reaction into an aldehyde and a ketone.

In glycolysis fructose-6-phosphate is converted to glucose-6-phosphate and can then be split by the aldol reaction into an aldehyde and a ketone.

In glycolysis fructose-6-phosphate is an aldol but is not itself split by the aldol reaction until phosphorylated to fructose-1,6-bisphosphate.

. Which of the following statements about the TCA cycle is correct?

Oxygen is used to oxidise the acetyl group carbons of acetyl-CoA in the TCA cycle.

Three molecules of NADH and one molecule of FADH₂ are produced in one turn of the TCA cycle.

Oxygen is not used in the TCA cycle, so the cycle can occur in anaerobic conditions.

The TCA cycle produces the water that is formed during the complete oxidation of glucose.

. Which of the following statements about the electron transport chain is correct?

The electron transport chain is made up of a chain of electron carriers with decreasing electron affinity.

The electron transport chain is made up of a chain of electron carriers with increasing redox potential.

The electron transport chain is made up of a chain of electron carriers with decreasing oxidising power.

The electrons transferred from carrier to carrier in the electron transport chain gain energy.

. Which of the following statements about the generation of ATP in the electron transport chains is correct?

The F₁subunit of the ATP synthase contains the motor which is driven to rotate by the proton flow.

The F₁subunit of the ATP synthase contains the catalytic centre that synthesizes ATP.

The F₀subunit of the ATP synthase binds ADP and Pi tightly before ATP synthesis occurs.

The F₀subunit of the ATP synthase contains the catalytic centre that synthesizes ATP.

. An uncoupler of oxidative phosphorylation would most likely lead to:

Inability to oxidise NADH by the electron transport chain.

Inability to produce heat by the operation of the electron transport chain.

Operation of the electron transport chain without ATP production.

A dependence on ADP for the electron transport chain to operate.

. What is the advantage of having two lipid bilayers around mitochondria?

They act as a store of phospholipids.

They prevent the entry of chemicals into mitochondria.

They protect the cell from free radicals.

They maintain a proton gradient.

. Which of the following statements about mitochondria is correct?

The outer mitochondrial membrane is extensively folded.

The mitochondrial matrix is filled with a concentrated solution of the glycolytic enzymes.

The inner mitochondrial membrane is permeable because it contains pores.

The inner mitochondrial membrane is extensively folded.

. Which of the following statements about the generation of ATP in the electron transport chain is correct?

The generation of ATP from ADP coupled to electron transfer occurs by substrate level phosphorylation as in glycolysis.

Electron transport generates a proton gradient across the outer mitochondrial membrane.

ATP synthase generation of ATP involves a rotating structure outside the inner mitochondrial membrane.

ATP synthase generation of ATP involves a rotating structure inside the inner mitochondrial membrane.

. Which of the following statements about the oxidative decarboxylation of pyruvate is correct?

The oxidative decarboxylation of pyruvate formed in aerobic glycolysis occurs in the cytosol.

The oxidative decarboxylation of pyruvate is catalysed by the enzyme pyruvate decarboxylase.

The oxidative decarboxylation of pyruvate is reversible since there is a large decrease of free energy in the reaction.

The oxidative decarboxylation of pyruvate forms acetyl-CoA which is fed into the citric acid cycle.

. How does substrate level phosphorylation differ from oxidative phosphorylation. One ,more than one , or all answers may be correct

There is no involvement of the electron transport chain in substrate level phosphorylation.

The two processes may take place in different compartments of the cell.

Substrate level phosphorylation is the conversion of GDP to GTP but not that of ADP to ATP.

Substrate level phosphorylation takes place in the erythrocyte but oxidative phosphorylation does not.

. Why is an intact inner mitochondrial membrane necessary for oxidative phosphorylation?

Oxidative phosphorylation depends upon the existence of a proton gradient which cannot be maintained if the membrane is damaged.

The membrane has to be intact because ATP synthase is a membrane bound enzyme.

The membrane needs to be intact as electron transport cannot take place on a damaged membrane.

The membrane needs to be intact for the cytochromes to be placed in the correct orientation for electron transport.

Chapter 13 Self-test questions

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