Q: Which of the following best describes the overall chemical reaction for photosynthesis in plants, as depicted in the provided images and study materials?

$$6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6 \text{O}_2$$

Q: Which of the following reactions is exergonic and can be coupled to drive the phosphorylation of ADP to ATP ($$\Delta G = +7.3$$ kcal/mol)?

$$\text{Phosphoenolpyruvate} \rightarrow \text{Pyruvate} + \text{HOPO}_3$$^{2-}$$ \,\, \Delta G = -14.8$$ kcal/mol

Question 1

Which of the following best describes the overall chemical reaction for photosynthesis in plants, as depicted in the provided images and study materials?

Accepted Answer

$$6 	ext{CO}_2 + 6 	ext{H}_2	ext{O} + 	ext{light energy} ightarrow 	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6 	ext{O}_2$$

Question 2

Which of the following statements about the energy changes in photosynthesis and cellular respiration is correct?

Accepted Answer

Photosynthesis is an endergonic process with $$\Delta G \u003e 0$$, while cellular respiration is an exergonic process with $$\Delta G \u003c 0.$$

Question 3

In the context of metabolism, which of the following best describes the difference between catabolism and anabolism?

Accepted Answer

Catabolism breaks down larger molecules to release energy, while anabolism builds larger molecules and consumes energy.

Question 4

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP stores energy in its high-energy phosphate bonds, which can be hydrolyzed to release energy for cellular processes.

Question 5

Which of the following reactions is exergonic and can be coupled to drive the phosphorylation of ADP to ATP ($$\Delta G = +7.3$$ kcal/mol)?

Accepted Answer

$$	ext{Phosphoenolpyruvate} ightarrow 	ext{Pyruvate} + 	ext{HOPO}_3$$^{2-}$$ \,\, \Delta G = -14.8$$ kcal/mol

Question 6

Which of the following best describes the role of NAD+ in cellular metabolism?

Accepted Answer

NAD+ acts as an oxidizing agent, accepting electrons and becoming reduced to NADH.

Question 7

During the citric acid cycle, which step directly produces a high-energy triphosphate molecule (GTP or ATP)?

Accepted Answer

The conversion of succinyl-CoA to succinate.

Question 8

Which of the following statements about the electron transport chain is correct?

Accepted Answer

It uses the energy from electrons transferred from NADH and FADH2 to pump protons across the inner mitochondrial membrane, creating a proton gradient.

Question 9

Which of the following best explains why the hydrolysis of ATP is exergonic?

Accepted Answer

The products (ADP and inorganic phosphate) are more stable and have lower free energy than ATP.

Question 10

Which of the following is a correct statement about the regulation of the citric acid cycle?

Accepted Answer

The cycle is activated by high levels of ADP and inhibited by high levels of NADH.

Question 11

Which of the following best describes the fate of the electrons carried by NADH and FADH2 in aerobic metabolism?

Accepted Answer

They are transferred to the electron transport chain, ultimately reducing oxygen to water.

Question 12

Which of the following is a real-world example of an oxidation-reduction reaction in biochemistry?

Accepted Answer

The reaction of glucose with Tollens' reagent, reducing Ag$$^+ to Ag(s) $$and oxidizing glucose.

Question 13

Which of the following best explains why energy must be released from food gradually in living organisms?

Accepted Answer

A sudden release of energy would be inefficient and could damage cells; gradual release allows for controlled energy use and heat production.

Question 14

Which of the following best describes the function of mitochondria in eukaryotic cells?

Accepted Answer

They are the site of most ATP production through oxidative phosphorylation.

Question 15

Which of the following is true about the relationship between the citric acid cycle and the electron transport chain?

Accepted Answer

The citric acid cycle produces reduced coenzymes (NADH, FADH2) that donate electrons to the electron transport chain.

Question 16

Which of the following best describes the role of coenzymes such as NAD+ and FAD in metabolism?

Accepted Answer

They act as electron carriers, cycling between oxidized and reduced forms.

Question 17

Which of the following best explains why the inner mitochondrial membrane is highly folded into cristae?

Accepted Answer

The folds increase the surface area for electron transport and ATP synthesis.

Question 18

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

Accepted Answer

A negative $$\Delta G$$ indicates a spontaneous, exergonic reaction.

Question 19

Which of the following best describes the fate of the acetyl group from acetyl-CoA in the citric acid cycle?

Accepted Answer

It is oxidized to two molecules of CO$$_2.$$

The Generation of Biochemical Energy: Photosynthesis, Cellular Respiration, and Metabolic Pathways

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