True or False: Proteins account for more than 50% of the dry mass of most cells and are instrumental in almost everything organisms do.

• True

• False

What does the Greek word "proteios," from which the word protein is derived, mean?

• "Strong"

• "Primary"

• "Life"

• "Structure"

What role do enzymes play in metabolism?

• They store energy in fat cells for later use.

• They act as catalysts, speeding up chemical reactions without being consumed.

• They act as transporters, transporting nutrients through the blood.

• They provide structural support to cells during anabolic activities and are recycled during catabolic ones.

True or false: Each type of protein has a unique 3-dimensional shape.

• True

• False

How many different amino acids are used to construct all proteins?

• 10

• 15

• 20

• 25

What is the bond called that links amino acids together in a protein?

• Hydrogen bond

• Ionic bond

• Peptide bond

• Glycosidic bond

Which of the following is the main function of enzymatic proteins?

• Acceleration of chemical reactions

• Storage of amino acids

• Transport of substances

• Protection against disease

What is an example of a defensive protein that plays a key role in the body’s immune system?

• Hemoglobin

• Antibodies

• Ovalbumin

• Keratin

Which protein acts as a hormone and regulates blood sugar levels?

• Insulin

• Collagen

• Keratin

• Actin

What is the main function of receptor proteins?

• Support

• Response of cell to chemical stimuli

• Movement

• Storage of lipids for cell membrane repair