Question 1

Which of the following best describes the flow of energy in biological systems, as illustrated in the chemical cycling diagram?

Accepted Answer

Light energy is converted to chemical energy by plants, and chemical energy is transferred through organisms, with heat lost from the ecosystem.

Question 2

Metabolism is defined as:

Accepted Answer

The sum of all chemical reactions that occur within a living organism, including both anabolic and catabolic pathways.

Question 3

Which of the following is an example of a catabolic pathway?

Accepted Answer

The breakdown of glucose during cellular respiration.

Question 4

Which type of energy is stored in the bonds of molecules and released during chemical reactions?

Accepted Answer

Chemical energy

Question 5

Refer to the metabolism diagram. Which process converts simple molecules into complex molecules, and what type of energy is required?

Accepted Answer

Anabolism; requires ATP

Question 6

ATP is able to drive biological reactions because:

Accepted Answer

It releases energy when its terminal phosphate bond is broken, forming ADP and $$P_i.$$

Question 7

How is ATP regenerated in cells?

Accepted Answer

By the addition of a phosphate group to ADP, using energy from catabolic reactions.

Question 8

Which statement best describes how enzymes work, based on the enzyme-substrate complex diagram?

Accepted Answer

Enzymes lower the activation energy ($$E_a) of a $$reaction by binding substrates at the active site and releasing products.

Question 9

Enzymes are able to bind only specific substrates because:

Accepted Answer

Their active site has a unique shape determined by the protein's tertiary structure and R groups, allowing only certain substrates to fit.

Question 10

Cofactors and coenzymes assist enzymes in metabolism by:

Accepted Answer

Providing additional chemical groups or atoms that help catalyze reactions.

Question 11

Competitive inhibition occurs when:

Accepted Answer

An inhibitor binds to the active site, preventing substrate binding.

Question 12

Non-competitive inhibition differs from competitive inhibition because:

Accepted Answer

Non-competitive inhibitors bind to an allosteric site, changing the enzyme's shape and reducing activity regardless of substrate concentration.

Question 13

According to the enzyme inhibition graph, what happens to the rate of reaction when a competitive inhibitor is added and substrate concentration increases?

Accepted Answer

The rate of reaction increases and can approach normal levels at high substrate concentrations.

Question 14

Why does the enzyme inhibition graph level off for each line?

Accepted Answer

The enzyme becomes saturated with substrate, and the maximum rate ($$V_{max}) is $$reached.

Question 15

Feedback inhibition is important to cells because:

Accepted Answer

It prevents the overproduction of end products by inhibiting the first enzyme in a pathway when the product accumulates.

Question 16

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

Accepted Answer

The pathway will halt, and intermediates before enzyme 3 will accumulate.

Question 17

Denaturation impacts enzyme structure and function by:

Accepted Answer

Disrupting the enzyme's three-dimensional structure, destroying the active site and reducing or eliminating function.

Question 18

Which environmental conditions can alter protein structure and function, and how?

Accepted Answer

Changes in temperature and pH can disrupt hydrogen bonds and ionic interactions, leading to denaturation and loss of function.

Question 19

Based on the enzyme temperature graph, what happens to the rate of reaction for human enzymes and thermophilic bacterial enzymes as temperature increases?

Accepted Answer

Human enzymes reach their optimal rate at $$37^\circC$$, while thermophilic bacterial enzymes reach their optimal rate at $$75^\circC.$$

Question 20

Which line on the pH graph represents the activity of an enzyme in the stomach under acidic conditions?

Accepted Answer

The black line (Pepsin)

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

Study Guide - Practice Questions

Study Guide - Flashcards