Q: Which of the following equations correctly represents the overall process of photosynthesis in plants?

$$6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 1

Which of the following best describes the main difference between fermentation and anaerobic respiration?

Accepted Answer

Anaerobic respiration uses an electron transport chain with a final electron acceptor other than oxygen, while fermentation does not use an electron transport chain.

Question 2

During strenuous exercise, human muscle cells switch to lactic acid fermentation. What is the primary purpose of this metabolic shift?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue producing ATP in the absence of oxygen.

Question 3

Which of the following equations correctly represents the overall process of photosynthesis in plants?

Accepted Answer

$$6CO_2 + 6H_2O + 	ext{light energy} ightarrow C_6H_{12}O_6$ + 6O_2$$

Question 4

A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. If the cell must generate ATP at the same rate, what will happen to its rate of glucose consumption?

Accepted Answer

It will increase because fermentation produces less ATP per glucose than aerobic respiration.

Question 5

Which molecule acts as the final electron acceptor in lactic acid fermentation?

Accepted Answer

Pyruvate

Question 6

In the context of metabolism, what is the main role of ATP in cellular work?

Accepted Answer

ATP couples exergonic and endergonic reactions, providing energy for cellular processes.

Question 7

Which of the following statements about the light reactions of photosynthesis is correct?

Accepted Answer

They use solar energy to split water, producing oxygen, ATP, and NADPH.

Question 8

What is the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To convert carbon dioxide into sugar using ATP and NADPH.

Question 9

Which of the following best explains why fermentation is considered an extension of glycolysis?

Accepted Answer

Fermentation allows glycolysis to continue by regenerating NAD$$^+ in $$the absence of oxygen.

Question 10

A marine bacterium uses sulfate ($$SO_4$$^{2-}$$) as its final electron acceptor in respiration. What type of metabolism is this?

Accepted Answer

Anaerobic respiration

Question 11

Which of the following is a correct statement about the energy transformations in photosynthesis?

Accepted Answer

Light energy is converted to chemical energy stored in sugars.

Question 12

Which of the following best describes the role of enzymes in metabolic reactions?

Accepted Answer

Enzymes lower the activation energy barrier, speeding up reactions.

Question 13

Which of the following is true about the relationship between catabolic and anabolic pathways in metabolism?

Accepted Answer

Catabolic pathways provide the energy and building blocks for anabolic pathways.

Question 14

Which of the following is a real-world example of lactic acid fermentation?

Accepted Answer

Muscle cells generating ATP during intense exercise

Question 15

If a classmate claims that the light reactions of photosynthesis can keep producing ATP and NADPH indefinitely as long as there is light, how would you respond?

Accepted Answer

This is incorrect because the Calvin cycle regenerates ADP and NADP$$^+$$, which are required for the light reactions to continue.

Question 16

Which of the following best explains why oxygen is released as a by-product during photosynthesis?

Accepted Answer

Oxygen is released when water is split to provide electrons for the light reactions.

Question 17

Which of the following statements about the free-energy change ($$\Delta G) of a $$reaction is correct?

Accepted Answer

A reaction with a negative $$\Delta G$$ can occur spontaneously.

Question 18

Which of the following is a key difference between obligate anaerobes and facultative anaerobes?

Accepted Answer

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

Question 19

Which of the following best describes the fate of NADH produced during glycolysis under anaerobic conditions?

Accepted Answer

NADH donates electrons to pyruvate or its derivatives, regenerating NAD$$^+$$ for glycolysis.

Metabolism: Fermentation and Anaerobic Respiration

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