Q: Which of the following is an example of a redox reaction in cellular respiration?

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}$$

Question 1

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy ($$E_a) $$barrier, speeding up the reaction without changing $$\Delta G.$$

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 3

Which statement correctly distinguishes aerobic respiration from fermentation?

Accepted Answer

Aerobic respiration requires oxygen and produces more ATP than fermentation.

Question 4

What is the main function of NAD$$^+ in $$cellular respiration?

Accepted Answer

It serves as an electron carrier, cycling between oxidized (NAD$$^+) $$and reduced (NADH) forms.

Question 5

Which process in cellular respiration produces the majority of ATP?

Accepted Answer

Oxidative phosphorylation

Question 6

A mutation alters the active site of an enzyme so that it no longer binds its substrate. What is the most likely consequence?

Accepted Answer

The enzyme will lose its catalytic activity for that substrate.

Question 7

Which of the following is an example of a redox reaction in cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{Energy}$$

Question 8

Which statement about substrate-level phosphorylation is correct?

Accepted Answer

It directly transfers a phosphate group from a substrate to ADP, forming ATP.

Question 9

In the citric acid cycle, what happens to the acetyl group from acetyl CoA?

Accepted Answer

It combines with oxaloacetate to form citrate, which is then decomposed back to oxaloacetate.

Question 10

Which of the following best explains the concept of 'induced fit' in enzyme activity?

Accepted Answer

The enzyme changes shape to better fit the substrate, enhancing catalytic ability.

Question 11

During glycolysis, what is the net gain of ATP and NADH per molecule of glucose?

Accepted Answer

2 ATP and 2 NADH

Question 12

Which of the following statements about chemiosmosis is correct?

Accepted Answer

It uses the energy stored in a proton ($$H^+) $$gradient to drive ATP synthesis.

Question 13

If a cell is deprived of oxygen, which process will continue to function?

Accepted Answer

Glycolysis

Question 14

Which of the following is true regarding the energy changes in a reaction catalyzed by an enzyme?

Accepted Answer

The enzyme lowers the activation energy ($$E_a) $$but does not affect the overall free energy change ($$\Delta G).$$

Question 15

Which molecule is oxidized and which is reduced in the following reaction: $$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$?

Accepted Answer

Glucose is oxidized; oxygen is reduced.

Question 16

Which of the following best describes the function of the electron transport chain in mitochondria?

Accepted Answer

It transfers electrons from NADH and FADH$$_2 to $$oxygen, pumping protons to create a gradient.

Question 17

Which of the following is a correct description of a coenzyme?

Accepted Answer

A non-protein molecule that assists enzymes, often acting as an electron carrier.

Question 18

Which process directly couples the redox reactions of the electron transport chain to ATP synthesis?

Accepted Answer

Chemiosmosis

Question 19

A patient is diagnosed with a genetic disorder that prevents the formation of the enzyme that catalyzes the first step of glycolysis. What is the most likely consequence?

Accepted Answer

The patient will be unable to produce ATP via substrate-level phosphorylation in glycolysis.

Enzymes and Cellular Respiration: Key Concepts in General Biology

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