N6.2 Digestion & Absorption of Proteins

How does the mouth contribute to protein digestion? (Check all that apply.)

• mechanical digestion

• moistening the bolus

• some hydrolysis occurs

• produces peptidases

Protein digestion in the stomach requires that ______ be changed into its active form called _____.

• pepsinogen; pepsin

• pepsin; pepsinogen

• HCl; pepsin

• pepsinogen; peptidase

In the small intestine, pepsin is deactivated by

• rising pH

• pancreatic peptidases

• pepsinogen

• bile

Single amino acids are liberated from their polypeptide chains by

• peptidases on the surfaces of intestinal cells

• pancreatic proteases

• pepsinogen

• bile

Digested amino acids move into villi cells through

• the membrane directly

• specific membrane transport proteins

• protein pumps

• gaps between cells

The body handles whole proteins better than pre-digested amino acids, such as you might find in supplements.

• true

• false

Some intestinal villi cells use the amino acids they absorb for their own energy needs.

• true

• false