Q: Which of the following equations correctly represents aerobic cellular respiration?

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

Question 1

Which of the following best describes the relationship between photosynthesis and cellular respiration as depicted in the first image (chloroplast and mitochondrion cycle)?

Accepted Answer

Photosynthesis converts light energy into chemical energy, which is then used by cellular respiration to produce ATP, releasing heat as a byproduct.

Question 2

Which of the following equations correctly represents aerobic cellular respiration?

Accepted Answer

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

Question 3

In the redox reaction $$\mathrm{Na} + \mathrm{Cl} \rightarrow \mathrm{Na}^+ + \mathrm{Cl}^-$$, which element is oxidized and which is reduced?

Accepted Answer

Na is oxidized; Cl is reduced.

Question 4

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

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 5

What is the main purpose of the electron transport chain in mitochondria?

Accepted Answer

To create a proton gradient that drives ATP synthesis via chemiosmosis.

Question 6

Which process produces the most ATP during cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 7

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

Accepted Answer

2 ATP and 2 NADH

Question 8

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates NAD+ so glycolysis can continue in the absence of oxygen.

Question 9

In the citric acid cycle, what happens to the two carbons that enter as acetyl-CoA?

Accepted Answer

They are released as two molecules of $$\mathrm{CO_2$}.$$

Question 10

Which of the following best explains why the energy yield from aerobic respiration is not 100% efficient?

Accepted Answer

Some energy is lost as heat due to the second law of thermodynamics.

Question 11

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

A phosphate group is directly transferred from a substrate to ADP to form ATP.

Question 12

Which of the following is a product of lactic acid fermentation?

Accepted Answer

Lactate

Question 13

What is the role of NAD+ in cellular respiration?

Accepted Answer

It acts as an electron carrier, accepting electrons during redox reactions.

Question 14

Which of the following best describes the fate of pyruvate in the absence of oxygen in muscle cells?

Accepted Answer

It is converted to lactate to regenerate NAD+.

Question 15

Which of the following is a key difference between fermentation and anaerobic respiration?

Accepted Answer

Fermentation does not use an electron transport chain, while anaerobic respiration does.

Question 16

Which of the following molecules can enter cellular respiration at multiple points, such as glycolysis or the citric acid cycle?

Accepted Answer

Amino acids, fatty acids, and glycerol

Question 17

A marine bacterium uses sulfate ($$\mathrm{SO_4$^{2-}}) as $$its final electron acceptor in respiration. What is a likely byproduct?

Accepted Answer

Hydrogen sulfide ($$\mathrm{H_2S})$$

Question 18

Which of the following best describes the function of ATP synthase?

Accepted Answer

It synthesizes ATP using the energy from a proton gradient across the mitochondrial membrane.

Question 19

Which of the following statements about facultative anaerobes is correct?

Accepted Answer

They can switch between aerobic respiration and fermentation depending on oxygen availability.

Question 20

Which of the following is a correct summary of the energy yield from one molecule of glucose during aerobic respiration?

Accepted Answer

About 30 to 32 ATP molecules are produced.

Cellular Respiration and Fermentation: Pathways of Energy Harvesting

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