Question 1

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

Accepted Answer

Anabolic pathways build complex molecules and consume energy, while catabolic pathways break down complex molecules and release energy.

Question 2

A diver climbs a platform, stands at the edge, and then jumps into the water. Which sequence correctly describes the energy transformations involved?

Accepted Answer

Kinetic energy (climbing) → potential energy (on platform) → kinetic energy (diving)

Question 3

Which statement best explains why the evolution of complex organisms does not violate the second law of thermodynamics?

Accepted Answer

Cells increase local order but release heat, increasing the entropy of their surroundings.

Question 4

Which of the following equations correctly represents the change in Gibbs free energy ($$\Delta G) $$for a reaction?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 5

Cellular respiration is summarized by the equation: $$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O}$$ with $$\Delta G = -2870\ \mathrm{kJ/mol}. $$Which of the following is true?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 6

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP couples exergonic and endergonic reactions by providing energy through hydrolysis.

Question 7

Why is adding heat to speed up cellular reactions not a viable strategy for living cells?

Accepted Answer

Heat would denature proteins and disrupt cellular structures.

Question 8

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy but do not change the $$\Delta G.$$

Question 9

A lysosomal lipase has an optimal pH of 4.5. What would happen to its activity if it were released into the cytosol (pH 7)?

Accepted Answer

Its activity would decrease because the cytosol pH is not optimal.

Question 10

Which of the following is an example of feedback inhibition in metabolic pathways?

Accepted Answer

A product of a pathway binds to an enzyme early in the pathway and decreases its activity.

Question 11

Which of the following best describes the difference between competitive and non-competitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, while non-competitive inhibitors bind to a different site on the enzyme.

Question 12

Which of the following reactions is an example of an endergonic process?

Accepted Answer

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

Question 13

Which of the following best explains why living cells are considered open systems?

Accepted Answer

They constantly exchange energy and matter with their surroundings.

Question 14

Which of the following is NOT a way that enzymes lower activation energy?

Accepted Answer

Changing the overall $$\Delta G of $$the reaction

Question 15

Which of the following best describes the role of ATP hydrolysis in active transport across cell membranes?

Accepted Answer

ATP hydrolysis provides energy to move solutes against their concentration gradient.

Question 16

Which of the following statements about the laws of thermodynamics is correct?

Accepted Answer

The second law states that every energy transformation increases the entropy of the universe.

Question 17

Which of the following is a real-life example of an exergonic reaction?

Accepted Answer

Cellular respiration in animals

Question 18

Which of the following best explains why cells never reach equilibrium?

Accepted Answer

Cells are open systems with a constant flow of materials in and out.

Question 19

Which of the following is a correct description of the catalytic cycle of an enzyme?

Accepted Answer

The enzyme binds to its substrate, forms an enzyme-substrate complex, converts substrate to product, and releases the product.

Topic4 Metabolism: Energy Transformation and Enzyme Function in Cells

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