Question 1

Which of the following best describes the relationship between photosynthesis and cellular respiration as shown in the first image?

Accepted Answer

Photosynthesis stores energy in organic molecules, while cellular respiration releases that energy for cellular work.

Question 2

During glycolysis (see image 2), what is the net gain of ATP and NADH per molecule of glucose?

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Referencing image 3, what are the products of pyruvate oxidation per pyruvate molecule?

Accepted Answer

Acetyl CoA, CO$$_2$$, and NADH

Question 4

In the citric acid cycle (image 4), which molecule combines with acetyl CoA to form citrate?

Accepted Answer

Oxaloacetate

Question 5

Which of the following best explains the role of the electron transport chain (image 5) in cellular respiration?

Accepted Answer

It uses electrons from NADH and FADH$$_2 to $$pump protons and create a proton gradient.

Question 6

According to image 6, what is the immediate energy source that drives ATP synthesis by ATP synthase?

Accepted Answer

The diffusion of H$$^+$$ down its concentration gradient

Question 7

Based on image 7, what determines whether pyruvate undergoes fermentation or enters the citric acid cycle?

Accepted Answer

The presence or absence of oxygen

Question 8

Image 8 shows regulation of glycolysis. Which molecule acts as an allosteric inhibitor of phosphofructokinase (PFK)?

Accepted Answer

ATP

Question 9

If the electron transport chain is inhibited (see image 9), what is the most immediate effect on cellular respiration?

Accepted Answer

ATP production by oxidative phosphorylation will decrease sharply.

Question 10

In alcoholic fermentation (image 10), what is the final electron acceptor?

Accepted Answer

Acetaldehyde

Question 11

In lactic acid fermentation (image 11), why must NAD^+ be regenerated?

Accepted Answer

To allow glycolysis to continue producing ATP

Question 12

Referencing image 12, which complex in the electron transport chain is the main site of NADH oxidation?

Accepted Answer

Complex I

Question 13

Based on the ATP yield table (image 13), which process produces the most ATP per glucose molecule?

Accepted Answer

Oxidative phosphorylation

Question 14

A poison blocks the flow of electrons between Complex III and Complex IV in the electron transport chain. What is the most likely result?

Accepted Answer

The proton gradient across the inner mitochondrial membrane decreases.

Question 15

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

Accepted Answer

Fats have more hydrogen atoms, leading to more electrons for the electron transport chain.

Question 16

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

Accepted Answer

Glycolysis

Question 17

Which enzyme is directly responsible for the synthesis of ATP during chemiosmosis (see image 6)?

Accepted Answer

ATP synthase

Question 18

Why is it important for protons to accumulate on one side of the mitochondrial membrane during cellular respiration?

Accepted Answer

To create a proton-motive force that drives ATP synthesis

Question 19

Which of the following is a correct summary of the flow of energy in cellular respiration?

Accepted Answer

Glucose → NADH/FADH$$_2$$ → Electron transport chain → Proton gradient → ATP

Question 20

Which of the following best explains why fermentation is necessary in the absence of oxygen?

Accepted Answer

It allows glycolysis to continue by regenerating NAD^+.

Energy and Enzymes: Cellular Respiration, Photosynthesis, and Metabolic Pathways

Study Guide - Practice Questions