$$\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$$

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

Question 1

Which of the following best describes the structure shown in the first image (with red, yellow, green, and blue regions) and its biological function?

Accepted Answer

A phospholipid bilayer forming the cell membrane, which regulates the movement of substances into and out of the cell.

Question 2

According to the first law of thermodynamics, which equation correctly represents the conservation of energy in a biological system?

Accepted Answer

$$\Delta E = q + w$$

Question 3

A student burns a potato (as shown in the image) to release energy. Which type of reaction is this, and what is the main product?

Accepted Answer

Exergonic reaction; carbon dioxide and water

Question 4

Which equation best represents the hydrolysis of ATP, as shown in the diagram with ATP, ADP, and phosphate?

Accepted Answer

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

Question 5

Which of the following is a real-life example of an exergonic reaction, as illustrated by the image of a car and cellular respiration?

Accepted Answer

Combustion of gasoline in a car engine

Question 6

In the diagram showing a reaction progress curve, what does the difference between the black and red curves represent?

Accepted Answer

The reduction of activation energy by an enzyme

Question 7

Which equation describes the change in free energy for a reaction, and what does a negative value indicate?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$; the reaction is spontaneous

Question 8

A cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

The cell will shrink because water leaves by osmosis.

Question 9

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The shape of the enzyme's active site matches only specific substrate molecules.

Question 10

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

Accepted Answer

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

Question 11

Which equation best represents the process of photosynthesis?

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 12

Which of the following statements about membrane transport is correct?

Accepted Answer

Active transport moves solutes against their concentration gradient using energy.

Question 13

A drug acts as a competitive inhibitor for an enzyme. What is the most likely effect on the enzyme's activity?

Accepted Answer

The drug binds to the active site, blocking substrate binding and reducing enzyme activity.

Question 14

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

Accepted Answer

ATP provides energy for chemical, transport, and mechanical work by transferring a phosphate group.

Question 15

Which of the following is a plausible consequence of increasing enzyme concentration in a reaction, based on the provided data?

Accepted Answer

The reaction rate will increase proportionally with enzyme concentration, up to a point.

Question 16

Which of the following is true about the effect of temperature on enzyme activity?

Accepted Answer

Enzyme activity is highest at the enzyme's optimal temperature, usually 35–40ºC for human enzymes.

Question 17

Which of the following best explains why plant cells do not burst in a hypotonic environment?

Accepted Answer

The cell wall exerts pressure that prevents excessive water intake.

Question 18

Which of the following is an example of facilitated diffusion?

Accepted Answer

Transport of glucose across the membrane via a specific protein channel.

Question 19

Which of the following best describes the process of exocytosis?

Accepted Answer

A cell exports bulky molecules by fusing a vesicle with the membrane.

The Working Cell: Energy, Enzymes, and Membrane Function

Study Guide - Practice Questions