How enzymes work

Question 1

Why does a reaction speed up as temperature rises towards the optimum?

• A. The substrate becomes an enzyme
• B. Molecules move faster, so enzyme and substrate collide more often
• C. The active site disappears
• D. The enzyme gets bigger

Question 2

Enzymes: which statement is NOT true?

• A. Enzymes are biological catalysts.
• B. Most human enzymes work best at about 37 °C.
• C. Enzymes are proteins.
• D. All enzymes work best at pH 7.

Question 3

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 70 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 4

Pepsin works best at pH 2. Where in the body does it work?

• A. the stomach
• B. the mouth
• C. the blood
• D. the small intestine

Question 5

Enzymes: which statement is NOT true?

• A. Enzymes are biological catalysts.
• B. Enzymes are not used up in the reactions they speed up.
• C. Enzymes are living things.
• D. Enzymes are proteins.

Question 6

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 37 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 7

What happens to an enzyme above its optimum temperature?

• A. It works faster and faster forever
• B. It is killed like a cell
• C. Its active site changes shape and it is denatured
• D. It turns into a different enzyme

Question 8

Enzymes: which statement is NOT true?

• A. Cold temperatures denature enzymes permanently.
• B. Most human enzymes work best at about 37 °C.
• C. Enzymes are not used up in the reactions they speed up.
• D. Enzymes are biological catalysts.

Question 9

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 36 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 10

Why can an enzyme only act on one type of substrate?

• A. Only that substrate fits the shape of its active site
• B. Enzymes are used up after one reaction
• C. Enzymes are too big
• D. Other substrates are dead

Question 11

Enzymes: which statement is NOT true?

• A. Most human enzymes work best at about 37 °C.
• B. All enzymes work best at pH 7.
• C. Enzymes are not used up in the reactions they speed up.
• D. Enzymes are biological catalysts.

Question 12

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 15 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 13

Pepsin works best at pH 2. Where in the body does it work?

• A. the small intestine
• B. the mouth
• C. the stomach
• D. the blood

Question 14

Enzymes: which statement is NOT true?

• A. All enzymes work best at pH 7.
• B. Enzymes are not used up in the reactions they speed up.
• C. Enzymes are proteins.
• D. Enzymes are biological catalysts.

Question 15

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 5 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 16

What happens to an enzyme above its optimum temperature?

• A. It is killed like a cell
• B. Its active site changes shape and it is denatured
• C. It works faster and faster forever
• D. It turns into a different enzyme