GI : Protein Digestion

Question 1

Brush border enzymes

Answer 1

Endopeptidases
Aminopeptidases
Dipeptidases

Question 2

Endopeptidases

Answer 2

can cleave anywhere in the protien

** Activates trypisn (trypsin can then activate other enzymes)

Question 3

Aminopeptidases

Answer 3

starts digesting protein from the amino terminal

Question 4

Dipeptidase

Answer 4

digests dipeptides

Question 5

where does protein digestion begin

Answer 5

stomach

Question 6

purpose of HCl in protein digestion

Answer 6

denatures dietary protein

Question 7

Pepsinogen

Answer 7

Secreted by Chief cells
Autoactivates at pH <5 (can further activate other pepsinogens)

degrades proteins into peptide fragments and some amino acids

Question 8

Secretion of Pepsinogen is regulated by ___ and ___

Answer 8

Histamine

Gastrin

Question 9

ion exchanger unique to parietal cells

Answer 9

H+/K exhanger

Question 10

Alkaline Tide

Answer 10

after eating we need more HCl - more Cl gets transffere into the parietal cell and more bicarbonate gets transferred to the blood (Bicarb/Cl exchanger) causing blood to become slightly alkaline

Question 11

function of stomach acid

Answer 11

denature proteins (make them accessible for proteases)

kill bacteria

activat pepsinogen (autoactivate at pH <5)

Question 12

Pepsinogen autoactivates at a pH less than ___

Answer 12

5

Question 13

Acts on amide (peptide bond) of Arg, Lys (basic amino acids)

Answer 13

Trypsin

Question 14

Acts on Tryp, Ty, Phe (aromatic a.a.) and on Met (sulfur containing) and Leu (basic a.a)

Answer 14

Chymotrypsin

Question 15

Acts on Ala, Gly, Ser (neutral a.a)

Answer 15

Elastase

Question 16

Acts on the carboxyterminal where you have Ala, Leu, Ile, Val

Answer 16

Carboxypeptidase A

Question 17

Acts on carboxyterminal where you have Arg, Lys (basic a.a)

Answer 17

Carboxypeptidase B

Question 18

what do brush border peptidases produce

Answer 18

free amino acids

di and tripeptides

Question 19

Transport of AA

Answer 19

Active transport - requires ATP

Na is taken into the cell with a.a and then pumped back out (Na/K pump - K in Na out)

Question 20

Transport of di and tripeptides

Answer 20

Active transport

converted to amino acid inside the mucosal cell (dipeptidase, tripeptidase)

Question 21

How do A.A get to the capillarie s

Answer 21

Diffusion (down [ ] grandient - high in mucosa low in capillaries) via simple or facilitated diffusion

once in the capillary they go to the portal system to be taken to the liver

Question 22

Essential amino acids

Answer 22

PVT TIM H(a) LL

Phenylalanine 
Valine 
Threonine 
Tyrptophan
Isoleusine 
Methionine 
Histatine 
(arginine in growing children) 
Leucine 
Lycine

Question 23

Amino acids are converted to ____ when carbohydrate products are broken down

Answer 23

urea (less toxic to the body)

Question 24

Positive Nitrogen Balance

Answer 24

Intake exceeds Secretion

occurs in growth and convalescence

Question 25

Negative Nitrogen Balance

Answer 25

Excretion exceeds amount taken in occurs in starvation, disease, and burns

Question 26

Hartnup Disease

Answer 26

congenital defect in the mechanism that transports neutral amino acids Neutral amino acids are not absorbed and therefore get excreted

Question 27

Cystinuria

Answer 27

congenital defect in the transport of Cysteine amino acids results in cysteine excretion from the body

Question 28

Food allergy

Answer 28

proteins enter the blood stream adn cause and immune response - foreign proteins that enter the blood stream provoke the formation of antibodies.