Question 1

Which of the following best describes the difference between anabolic and catabolic pathways in metabolism, as shown in the metabolic cycle diagram?

Accepted Answer

Anabolic pathways build complex molecules from simple molecules, requiring energy input, while catabolic pathways break down complex molecules into simple molecules, releasing energy.

Question 2

Which type of energy is stored in the bonds of molecules such as glucose and ATP?

Accepted Answer

Chemical energy

Question 3

According to the laws of thermodynamics, what happens to energy as it flows through an ecosystem, as depicted in the energy flow diagram?

Accepted Answer

Energy flows in as light, is converted to chemical energy, and some is lost as heat at each step.

Question 4

Which of the following best explains how ATP drives cellular work?

Accepted Answer

ATP transfers a phosphate group to other molecules, increasing their energy and allowing reactions to proceed.

Question 5

Which statement about enzyme-substrate interactions is supported by the enzyme mechanism diagram?

Accepted Answer

The active site of an enzyme binds substrates through weak interactions, such as hydrogen bonds and ionic bonds.

Question 6

Which of the following best describes the role of cofactors and coenzymes in enzyme function?

Accepted Answer

They assist enzymes by stabilizing substrate binding or participating in the reaction, often as non-protein molecules.

Question 7

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 8

How can the effects of a competitive inhibitor be overcome in an enzyme-catalyzed reaction?

Accepted Answer

By increasing the substrate concentration.

Question 9

Which of the following best explains why the rate of reaction plateaus at high substrate concentrations in the enzyme inhibition graph?

Accepted Answer

All enzyme active sites are occupied, so the reaction cannot go faster.

Question 10

Which environmental condition would most likely cause denaturation of a human enzyme, as shown in the temperature and pH graphs?

Accepted Answer

A temperature of $$75^\circ C$$ and pH 2

Question 11

Which line in the pH graph represents the activity of pepsin, a stomach enzyme, and why?

Accepted Answer

The black line, because pepsin works best at acidic pH.

Question 12

Feedback inhibition is important in metabolic pathways because:

Accepted Answer

It prevents the accumulation of excess end products by inhibiting an early enzyme in the pathway.

Question 13

If enzyme 3 in a metabolic pathway stops functioning, what is the most likely outcome?

Accepted Answer

Intermediates before enzyme 3 will accumulate, and products after enzyme 3 will not be produced.

Question 14

Which of the following best describes how beta-amyloid peptide contributes to Alzheimer's disease, based on the diagram and reading?

Accepted Answer

Beta-amyloid peptide accumulates and forms plaques in the brain, disrupting cell function.

Question 15

In the reaction catalyzed by beta-secretase (BACE) in Alzheimer's disease, what are the enzyme, substrate, and product?

Accepted Answer

Enzyme: BACE; Substrate: APP; Product: beta-amyloid peptide

Question 16

Which structural feature must a drug have to act as a competitive inhibitor of an enzyme?

Accepted Answer

It must resemble the substrate and fit into the enzyme's active site.

Question 17

Why can't non-competitive inhibition be overcome by increasing substrate concentration?

Accepted Answer

Because the inhibitor binds to a different site, changing the enzyme's shape and reducing its activity regardless of substrate concentration.

Question 18

Which equation correctly represents the hydrolysis of ATP to ADP and inorganic phosphate?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 19

Which of the following best explains why thermophilic bacteria have enzymes with higher optimal temperatures than human enzymes, as shown in the temperature graph?

Accepted Answer

Thermophilic enzymes are adapted to function at high temperatures, maintaining their structure and activity.

Study Guide: Energy, Enzymes, and Metabolism in Biological Systems

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