Question 1

Which of the following best describes catabolic pathways in metabolism?

Accepted Answer

They break down larger molecules into smaller ones, releasing energy.

Question 2

Which statement correctly applies the first law of thermodynamics to biological systems?

Accepted Answer

Energy is transferred and transformed, but the total amount remains constant.

Question 3

A metabolic pathway converts substrate A to product D through intermediates B and C. If enzyme 2 (which converts B to C) is inhibited, what will happen?

Accepted Answer

Intermediate B will accumulate and product D will decrease.

Question 4

Which of the following is an example of an anabolic reaction?

Accepted Answer

Synthesis of proteins from amino acids

Question 5

Which type of energy is stored in the chemical bonds of glucose?

Accepted Answer

Potential energy

Question 6

According to the second law of thermodynamics, what happens to the entropy of a closed system over time?

Accepted Answer

Entropy increases as energy is lost as heat.

Question 7

Which of the following reactions is exergonic?

Accepted Answer

Hydrolysis of ATP to ADP and Pi

Question 8

If a reaction has a negative change in free energy ($$\Delta G \u003c 0$$), what does this indicate?

Accepted Answer

The reaction is spontaneous and releases energy.

Question 9

Which of the following best explains why metabolic pathways are often organized as chains of reactions?

Accepted Answer

Each step allows for regulation and control of the pathway.

Question 10

Which process is an example of a spontaneous process in cells?

Accepted Answer

Diffusion of oxygen across a membrane

Question 11

Which of the following equations correctly represents the overall reaction for aerobic respiration of glucose?

Accepted Answer

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

Question 12

Which statement best describes the role of enzymes in metabolic pathways?

Accepted Answer

Enzymes lower the activation energy, speeding up reactions.

Question 13

Which of the following is true about the relationship between catabolism and anabolism?

Accepted Answer

Catabolism provides energy and building blocks for anabolism.

Question 14

In a metabolic pathway, what is the primary function of an intermediate such as B in the sequence A → B → C → D?

Accepted Answer

It serves as a substrate for the next enzyme-catalyzed reaction.

Question 15

Which of the following best describes the difference between exergonic and endergonic reactions?

Accepted Answer

Exergonic reactions release energy, while endergonic reactions require energy input.

Question 16

Which of the following is a real-world example of a catabolic process?

Accepted Answer

Digestion of starch into glucose in the human gut

Question 17

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Metabolic pathways can be cyclic, linear, or branched.

Question 18

Which of the following best explains why energy transformations in metabolism are never 100% efficient?

Accepted Answer

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

Question 19

Which of the following is a correct statement about the role of oxygen in cellular respiration?

Accepted Answer

Oxygen acts as the terminal electron acceptor, allowing the release of energy from glucose.

Question 20

Which of the following best describes the relationship between free energy change ($$\Delta G) $$and spontaneity of a reaction?

Accepted Answer

A negative $$\Delta G$$ means the reaction is spontaneous.

Introduction to Metabolism: Key Concepts and Pathways

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