Proteins Digestion and Absorption

Question 1

How digestive enzymes break down large molecules

Answer 1

Hydrolytic cleavage

Question 2

Main areas of protein digestion

Answer 2

Stomach and small intestine

Question 3

What theory do enzymes work by

Answer 3

Enzyme-substrate complex

Question 4

Enzyme in lining of stomach

Answer 4

Pepsinogen. Inactive form of pepsin. Activated by change of pH when entering HCl, by changing of shape

Question 5

Pepsin Outline

Answer 5

Endopeptidase (cuts peptide bonds in the middle of chain). Cleaves at hydrophobic amine side of aa

Question 6

Enteropeptidase Location, Substrate and Product

Answer 6

Small intestine lining, trypsinogen and tripsin

Question 7

Trypsin Location and formation

Answer 7

Enzyme enteropeptidase works on substrate trypsinogen

Question 8

Chymotrypsin Location and Formation

Answer 8

Small intestine, enzyme trypsin works on substrate chymotrypsinogen

Question 9

Elastase Location and formation

Answer 9

Small intestine, enzyme trypsin acts on substrate proelastase

Question 10

Carboxypeptidase Location and function

Answer 10

Small intestine, enzyme trypsin acts on substrate procarboxypeptidase

Question 11

Pancreatic Endopeptidases

Answer 11

Trypsin (basic aas) chymotrypsin (hydrophobic aas) and elastase (small aas)

Question 12

Pancreatic carboxypeptidases

Answer 12

Carboxypeptidase A (hydrophobic aas) and Carboxypeptidase B (basic aas)

Question 13

Enzymes at brush border

Answer 13

Aminopeptidase, endopeptidase, carboxypeptidase and dipeptidase

Question 14

Protein Digestion Products

Answer 14

Tetrapeptides, tripeptides, dipeptides and amino acids

Question 15

Main site of protein absorption

Answer 15

Small intestine (illeum), through endothelial cell lining

Question 16

Small Intestine Unit of Absorption

Answer 16

Villus. Tubes of length 0.5-1.5mm, covered in simple columnar endothelium. Form the brush border

Question 17

Epithelial cells in GI functions

Answer 17

Enterocytes. Protection, secretion and absorption

Question 18

Peptide absorption

Answer 18

Fastest form of protein absorption (most absorbed this way). Proteins absorbed in chains instead of aas. Coupled to Na and H + exchange (enters with H flow). Secondary active transport

Question 19

Protein across basolateral membrane outline

Answer 19

Moves to interstitial fluid by facilitated diffusion and co-transport. Glutamate and Aspartate provide energy.Transported to liver via hepatic portal vein