Question 1

Which of the following best describes the role of an enzyme in a biological reaction?

Accepted Answer

Enzymes decrease the activation energy required for a reaction.

Question 2

Which effect is responsible for lowering the activation energy by inducing strain on the substrate's bonds?

Accepted Answer

Energy effect

Question 3

A reaction catalyzed by alcohol dehydrogenase converts ethanol to acetaldehyde. Which class of enzyme is responsible for this reaction?

Accepted Answer

Oxidoreductase

Question 4

Which subclass of hydrolases is responsible for breaking peptide bonds in proteins?

Accepted Answer

Proteases

Question 5

Which enzyme class catalyzes the transfer of a phosphoryl group between substrates?

Accepted Answer

Kinase (a subclass of transferases)

Question 6

Which enzyme class requires ATP hydrolysis to provide energy for the reaction?

Accepted Answer

Ligases

Question 7

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Highly specific enzymes catalyze one type of reaction for a single substrate.

Question 8

Why does the induced fit model more accurately describe substrate binding than the lock-and-key model?

Accepted Answer

The induced fit model suggests the enzyme changes shape to fit the substrate.

Question 9

Which statement about enzyme activity is true?

Accepted Answer

Enzyme activity reaches a maximum rate when substrate concentration is high.

Question 10

A human enzyme is placed in a thermophile organism living at 75°C. What is the likely outcome?

Accepted Answer

The enzyme will be inactive due to denaturation.

Question 11

Which of the following is a coenzyme commonly required for oxidoreductase reactions?

Accepted Answer

NAD+

Question 12

Which graph best represents the effect of increasing enzyme concentration (with excess substrate) on reaction rate?

Accepted Answer

A straight line with positive slope

Question 13

Which enzyme class catalyzes the rearrangement of atoms within a molecule to form an isomer?

Accepted Answer

Isomerases

Question 14

Which of the following best describes the effect of temperature on enzyme activity?

Accepted Answer

Enzyme activity increases with temperature and then decreases after reaching an optimum.

Question 15

Which of the following is true regarding the catalytic cycle of an enzyme?

Accepted Answer

Enzymes return to their original state after the reaction.

Question 16

Which of the following is a real-life example of a transferase enzyme?

Accepted Answer

Phosphofructokinase transferring a phosphoryl group to fructose-6-phosphate

Question 17

Which enzyme class catalyzes the addition or removal of a small molecule to/from a double bond?

Accepted Answer

Lyases

Question 18

Which of the following statements about enzyme-substrate binding is correct?

Accepted Answer

Both highly specific and nonspecific enzymes require chemically compatible pockets for substrate binding.

Question 19

Which of the following best explains why substrate concentration increases reaction rate up to a maximum?

Accepted Answer

All enzyme active sites become saturated with substrate, so the rate cannot increase further.

Question 20

Which of the following is a real-world example of a hydrolase enzyme?

Accepted Answer

Trypsin hydrolyzing peptide bonds in proteins during digestion

Lecture 10

Guida di studio - Domande di pratica