Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways break down molecules and release energy, while anabolic pathways build larger molecules from smaller ones and require energy.

Question 2

A scientist adds a competitive inhibitor to an enzyme-catalyzed reaction. Which of the following best explains what will happen to the reaction rate if the substrate concentration is greatly increased?

Accepted Answer

The reaction rate will increase and may approach the rate without inhibitor, because high substrate outcompetes the inhibitor for the active site.

Question 3

Which of the following equations correctly represents the change in free energy for a chemical reaction, and what does each term represent?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$, where $$\Delta G is $$free energy, $$\Delta H is $$enthalpy, $$T is $$temperature in kelvin, and $$\Delta S is $$entropy.

Question 4

During glycolysis, which molecule is oxidized and which is reduced?

Accepted Answer

Glucose is oxidized and NAD+ is reduced to NADH.

Question 5

Which of the following best explains why an organism is considered an open system?

Accepted Answer

It exchanges both energy and matter with its surroundings, such as taking in food and releasing heat and waste.

Question 6

A patient is exposed to a high fever (42°C) for several hours. Which of the following best describes what is likely to happen to most of their enzymes?

Accepted Answer

Enzymes will denature, losing their specific shape and function, leading to decreased reaction rates.

Question 7

Which of the following statements about ATP is correct?

Accepted Answer

ATP is a nucleotide composed of adenine, ribose, and three phosphate groups.

Question 8

Which of the following best describes the role of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

It uses electrons from NADH and FADH2 to pump H+ across the inner mitochondrial membrane, creating a gradient that drives ATP synthesis.

Question 9

Which of the following is a correct summary of the products generated per acetyl-CoA during one turn of the citric acid cycle?

Accepted Answer

2 CO2, 3 NADH, 1 FADH2, and 1 ATP (or GTP)

Question 10

A plant is exposed to only green light. Which of the following best predicts the effect on its rate of photosynthesis, and why?

Accepted Answer

Photosynthesis will be least efficient because green light is mostly reflected or transmitted, not absorbed.

Question 11

Which of the following best explains why the action spectrum for photosynthesis is broader than the absorption spectrum of chlorophyll a?

Accepted Answer

Accessory pigments such as chlorophyll b and carotenoids absorb additional wavelengths and transfer energy to chlorophyll a.

Question 12

Which of the following correctly traces the movement of electrons during linear (noncyclic) electron flow in the light reactions of photosynthesis?

Accepted Answer

H2O → Photosystem II → ETC → Photosystem I → NADP+

Question 13

Which of the following best describes the main consequence of photorespiration in C3 plants?

Accepted Answer

It uses energy, releases previously fixed CO2, and reduces sugar production.

Question 14

Which adaptation allows C4 plants to minimize photorespiration?

Accepted Answer

They concentrate CO2 near rubisco using spatial separation of initial fixation and the Calvin cycle.

Question 15

Which of the following best describes the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation transfers a phosphate directly from a substrate to ADP, while oxidative phosphorylation uses a proton gradient to drive ATP synthase.

Question 16

A mutation causes the F0 portion of ATP synthase to become nonfunctional. Which of the following would be the most immediate effect on cellular respiration?

Accepted Answer

Protons would not flow through ATP synthase, so ATP production by oxidative phosphorylation would decrease sharply.

Question 17

Which of the following is a correct description of the two main stages of photosynthesis and where they occur?

Accepted Answer

Light reactions occur in the thylakoid membrane, and the Calvin cycle occurs in the stroma.

Question 18

Which of the following best explains why the exact number of ATP molecules produced from one glucose molecule during cellular respiration cannot be stated precisely?

Accepted Answer

The yield varies due to differences in how cytosolic NADH enters mitochondria, proton leak, transport costs, and membrane gradient efficiency.

Question 19

Which of the following is a real-life example of an anabolic reaction?

Accepted Answer

Synthesis of muscle protein from amino acids after exercise.

Metabolism, Cellular Respiration, and Photosynthesis: Study Guide for General Biology

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