Protein: Digestion And Absorption

Question 1

In gastric digestion of protein, what is the name of the protease that begins cleaving off bonds in peptides?

Answer 1

Pepsin

Question 2

What are the 2 types of proteases?

Answer 2

Endopeptidase and exopeptidases

Question 3

What are the 2 zymogens secreted in the gastric phase of protein digestion?

Answer 3

HCl and pepsinogen

Question 4

Which bonds are cleaved by endopeptidases?

Answer 4

Those not next to the N and C terminus

Question 5

Exopeptidases cleave bonds where in the peptide?

Answer 5

Next to the N and C terminus

Question 6

HCl is secreted by which cells?

Answer 6

Parietal

Question 7

Pepsinogen is the inactive form of what enzyme?

Answer 7

Pepsin

Question 8

What activates pepsin?

Answer 8

HCl or itself

Question 9

What does the pancreas secrete

Answer 9

Enzymes for digestion and sodium bicarbonate

Question 10

What is the function of sodium bicarbonate?

Answer 10

To neutralize chyme in the duodenum

Question 11

The pancreas is stimulated to secrete zymogens by what molecule ?

Answer 11

CCK from the duodenum

Question 12

What are the 3 zymogens secreted by the pancreas?

Answer 12

Trypsinogen, chymotrypsinogen, and procarboxypeptidase

Question 13

How are zymogens activated?

Answer 13

The brush border of the git secretes endopeptidases such as entrokinase which activate trypsinogen into trypsin which in turn activates the other zymogens and itself

Question 14

Where is protein absorbed?

Answer 14

Duodenum and jejunum

Question 15

Where is protein absorbed to?

Answer 15

Into the bloodstream or into the enterocyte itself

Question 16

Absorption is driven by what?

Answer 16

Gradients

Question 17

How are amino acids absorbed?

Answer 17

The sodium/potassium pump creates a gradient inside the enterocyte. When sodium comes into the cell, it brings in an AA through an AA carrier

Question 18

How are peptides absorbed?

Answer 18

The enterocyte creates a proton gradient by pumping sodium in and protons out. The peptide carrier brings in a peptide and protons. The peptide is then hydrolyzed inside the enterocyte into an AA

Question 19

How are AA transported in the blood ?

Answer 19

As a free amino acid

Question 20

Where do the AA go?

Answer 20

Into portal blood, then to liver, then to tissues

Question 21

What is the first tissue that uses AA?

Answer 21

The enterocyte itself

Question 22

How can intact proteins be absorbed?

Answer 22

Through tight junctions of enterocyte or through endocytosis

Question 23

What is closure in neonates?

Answer 23

When the small intestine loses the ability to absorb intact proteins, such as Immunoglobulins, for passive immunity

Question 24

Which cells secrete pepsinogen?

Answer 24

Chief cells

Question 25

What are the proteases naturally found in seeds that decrease protein gestation digestion by slowing activation of proteases?

Answer 25

Trypsin inhibitors