$$\text{C}_6\text{H}_{12}\text{O}_6 + 6 \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{Energy}$$

Question 1

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

It functions as an electron carrier, accepting electrons and becoming reduced to NADH.

Question 2

During glycolysis, what is the net gain of ATP molecules produced per molecule of glucose?

Accepted Answer

$$2$$

Question 3

Which of the following statements about enzyme activity is correct?

Accepted Answer

Enzymes lower the activation energy ($$E_A) of a $$reaction, increasing the rate of the reaction.

Question 4

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and blocking substrate entry.

Question 5

Which of the following equations correctly represents the overall reaction for aerobic cellular respiration?

Accepted Answer

$$	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6 	ext{O}_2 ightarrow 6 	ext{CO}_2 + 6 	ext{H}_2	ext{O} + 	ext{Energy}$$

Question 6

Why does the rate of an enzyme-catalyzed reaction decrease at temperatures above the enzyme's optimum?

Accepted Answer

The enzyme denatures, losing its functional shape.

Question 7

Which of the following best explains why fats yield more ATP per gram than carbohydrates during cellular respiration?

Accepted Answer

Fats have more hydrogen atoms, providing more high-energy electrons for the electron transport chain.

Question 8

In the citric acid cycle, what is the main function of NADH and FADH2?

Accepted Answer

They donate electrons to the electron transport chain for ATP production.

Question 9

Which of the following is a correct description of feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway binds to an allosteric site on an enzyme, inhibiting the pathway.

Question 10

Which of the following statements about fermentation is true?

Accepted Answer

Fermentation regenerates NAD+ by transferring electrons to pyruvate or its derivatives.

Question 11

A patient is exposed to sarin gas, which covalently binds to acetylcholinesterase. What is the most likely effect on the enzyme?

Accepted Answer

The enzyme will be irreversibly inhibited, leading to loss of function.

Question 12

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind elsewhere and change the enzyme's shape.

Question 13

Which of the following is a real-life example of feedback inhibition?

Accepted Answer

The end product isoleucine inhibiting threonine deaminase in amino acid biosynthesis.

Question 14

Which of the following best explains why increasing substrate concentration can overcome competitive inhibition but not noncompetitive inhibition?

Accepted Answer

Competitive inhibitors bind reversibly to the active site, so more substrate can outcompete them.

Question 15

Which of the following is the correct sequence of energy flow during cellular respiration?

Accepted Answer

glucose → NADH → electron transport chain → proton-motive force → ATP

Question 16

Which of the following best describes the process of chemiosmosis in mitochondria?

Accepted Answer

The movement of H+ ions down their concentration gradient through ATP synthase, driving ATP synthesis.

Question 17

A person is exercising vigorously and their muscles begin to produce lactic acid. Which of the following best explains this phenomenon?

Accepted Answer

Their muscle cells are undergoing lactic acid fermentation due to insufficient oxygen.

Question 18

Which of the following statements about the optimal conditions for enzyme activity is correct?

Accepted Answer

Enzymes have different optimal pH and temperature depending on their environment and function.

Question 19

Which of the following is a correct statement about the fate of pyruvate in the presence of oxygen in eukaryotic cells?

Accepted Answer

Pyruvate enters the mitochondrion and is converted to acetyl CoA.

Cellular Respiration, Fermentation, and Enzyme Regulation: Study Notes for General Biology

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