Question 1

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

Accepted Answer

Catabolic reactions break down large molecules into smaller ones, releasing energy, while anabolic reactions build large molecules from smaller ones, requiring energy.

Question 2

According to the law of conservation of matter and energy, which statement is correct regarding cellular respiration?

Accepted Answer

Matter and energy are transformed into different forms, but are neither created nor destroyed.

Question 3

A reaction has a negative Gibbs free energy ($$\Delta G \u003c 0). $$Which of the following statements is true?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 4

Which equation correctly represents the overall process of aerobic cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + O_2$ \rightarrow CO_2$ + H_2O$$

Question 5

Which step of cellular respiration occurs in the cytoplasm?

Accepted Answer

Glycolysis

Question 6

If the electron transport chain in mitochondria is inhibited, what is the most immediate effect on ATP production?

Accepted Answer

ATP production decreases dramatically because oxidative phosphorylation is blocked.

Question 7

Which molecule acts as the final electron acceptor in the mitochondrial electron transport chain?

Accepted Answer

O$$_2$$

Question 8

During fermentation in muscle cells, which molecule is produced to regenerate NAD+?

Accepted Answer

Lactic acid

Question 9

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

Accepted Answer

Enzymes lower the activation energy, speeding up reactions without being consumed.

Question 10

A student adds acid to an enzyme solution and observes a loss of activity. What is the most likely explanation?

Accepted Answer

The enzyme was denatured due to pH change, altering its active site.

Question 11

Which of the following is true about redox reactions in cellular respiration?

Accepted Answer

Oxidation involves losing electrons, and reduction involves gaining electrons.

Question 12

In photosynthesis, which process directly produces ATP and NADPH?

Accepted Answer

Light-dependent reactions

Question 13

If the Calvin cycle is blocked but the light reactions continue, what builds up in the chloroplast?

Accepted Answer

ATP and NADPH

Question 14

Which enzyme is responsible for fixing CO$$_2 in $$the Calvin cycle?

Accepted Answer

Rubisco

Question 15

Which of the following best explains why oxygen is used as the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen is highly electronegative, allowing maximum energy extraction from electrons.

Question 16

Which of the following is a correct description of chemiosmosis in mitochondria?

Accepted Answer

H$$^+$$ ions flow down their gradient through ATP synthase, producing ATP.

Question 17

Which of the following is an example of coupling an exergonic reaction to drive an endergonic reaction in cells?

Accepted Answer

Hydrolysis of ATP is paired with glucose phosphorylation.

Question 18

During the citric acid cycle, which molecule is regenerated at the end of the cycle to allow the cycle to continue?

Accepted Answer

Oxaloacetate

Question 19

Which of the following best describes the flow of energy in photosynthesis?

Accepted Answer

Light energy is converted to chemical energy in ATP and NADPH, then to chemical energy in sugar.

Question 20

Which process is responsible for splitting water and releasing O$$_2$$ during photosynthesis?

Accepted Answer

Photosystem II

Metabolism, Cellular Respiration, and Photosynthesis: Core Concepts and Mechanisms

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