Question 1

Consider the reaction: $$\mathrm{C_2H_6 + 2O_2 \rightarrow 2CO_2 + 3H_2O}. $$Based on oxidation-reduction principles, which atoms are oxidized and which are reduced during this reaction?

Accepted Answer

Carbon atoms are oxidized, hydrogen atoms are oxidized, and oxygen atoms are reduced.

Question 2

Which of the following best describes the primary function of cellular respiration in eukaryotic cells?

Accepted Answer

Convert chemical potential energy in organic molecules to chemical potential energy cells can readily use to do work (ATP).

Question 3

Which of the following is a net input of aerobic cellular respiration? Select all that apply.

Accepted Answer

Glucose

Question 4

Which stage of cellular respiration does NOT occur in the mitochondria?

Accepted Answer

Glycolysis

Question 5

By the end of glycolysis, which of the following has occurred?

Accepted Answer

Glucose has been broken down into pyruvate, and a small amount of ATP and NADH have been produced.

Question 6

During cellular respiration, H$$^+$$ ions are moved from the mitochondrial matrix to the intermembrane space. What does this mean for the pH of the matrix compared to the intermembrane space?

Accepted Answer

The matrix is less acidic and has a higher pH than the intermembrane space.

Question 7

What is the function of NADH and FADH$$_2 in $$cellular respiration?

Accepted Answer

They carry high-energy electrons to the electron transport chain.

Question 8

What happens to O$$_2$$ during cellular respiration? Select all that apply.

Accepted Answer

It accepts electrons from the electron transport chain.

Question 9

How does ATP synthase produce ATP from ADP and inorganic phosphate (Pi)?

Accepted Answer

It allows hydrogen ions to move down their gradient and ultimately uses that energy to synthesize ATP from ADP and inorganic phosphate.

Question 10

Which molecules are produced by glycolysis, pyruvate processing, and the citric acid cycle that are needed for electron transport and oxidative phosphorylation? Select all that apply.

Accepted Answer

NADH

Question 11

A soil bacterium produces a chemical that binds to complex III of another bacterium's electron transport chain, blocking electron transfer. What effect does this have on the other bacterium's ability to produce ATP by oxidative phosphorylation?

Accepted Answer

Decrease because H$$^+$$ cannot be moved across the membrane and create a gradient if electrons cannot be transported.

Question 12

When oxygen is not available, some cells carry out fermentation. How does fermentation enable ATP production in the absence of oxygen?

Accepted Answer

It regenerates NAD$$^+$$ and allows ATP synthesis by substrate-level phosphorylation to continue during glycolysis.

Question 13

A group of students grows yeast cells with and without oxygen, providing glucose for energy. If both cultures require the same amount of ATP per unit time, which will require more glucose per unit time and why?

Accepted Answer

The yeast under anaerobic conditions will require more glucose per unit time because aerobic respiration produces far more ATP per glucose than fermentation produces.

Question 14

Which of the following pairs of reactions could be coupled so that the energy released by the exergonic reaction provides all the energy needed for the endergonic reaction? (Let Reaction 1 be endergonic and Reaction 2 be exergonic.)

Accepted Answer

Reaction 1: $$\Delta G = 31$$ kcal/mol; Reaction 2: $$\Delta G = -43$$ kcal/mol

Question 15

Refer to the diagram tracking carbon and energy through cellular respiration. What molecule is produced as a waste product when carbon-carbon bonds are broken during pyruvate processing and the citric acid cycle?

Accepted Answer

Carbon dioxide

Question 16

Based on the metabolic pathway diagram, which macromolecules can be used as sources of energy for cellular respiration?

Accepted Answer

Carbohydrates, fats, and proteins

Question 17

Which molecule acts as the final electron acceptor in the electron transport chain during aerobic cellular respiration?

Accepted Answer

O$$_2$$

Question 18

During oxidative phosphorylation, what is the immediate source of energy used by ATP synthase to produce ATP?

Accepted Answer

The hydrogen ion gradient across the mitochondrial membrane

Cellular Respiration and Energy Conversion Study Guide

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