Enzymes and Vitamins

Which of the following is the reduced form of vitamin C?

• Ascorbate

• Ascorbic acid

• Dehydroascorbic acid

• Hydroascorbic acid

A molecule that inactivates enzymes by forming a strong covalent bond to an amino acid side-chain group at the enzyme's active site.

• Enzyme inhibitor

• competitive enzyme inhibitor

• noncompetitive enzyme inhibitor

• irreversible enzyme inhibitor

It is an enzyme that is composed only of proteins.

• Simple enzyme

• Conjugated enzyme

• Apoenzyme

• Holoenzyme

An enzyme that catalyzes a hydrolysis reaction in which the addition of a water molecule to a bond causes the bond to break.

• oxidoreductase

• transferase

• hydrolase

• lyase

What is the relatively small part of an enzyme's structure that is actually involved in catalysis?

• substrate

• cofactor

• active site

• enzyme-substrate complex

What model of enzyme action is depicted by the image?

• Enzyme-substrate complex

• Lock-and-key model

• Induced-Fit Model

• Absolute Model

Grapefruit is an excellent source of vitamin C. The pink and red colors of grapefruit are due to the carotenoid __________.

• Lycopene

• Bromelain

• Anthocyanin

• Phytochemical

Vitamins can be synthesized by the human body.

• True

• False

Which of the following is NOT a fat-soluble vitamin?

• Vitamin A

• Vitamin K

• Vitamin E

• Vitamin C

A vitamin that was once called the "yellow vitamin" because of its color.

• Thiamin

• Niacin

• Biotin

• Riboflavin