Digestion and Absorption of Proteins Flashcards Preview

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Flashcards in Digestion and Absorption of Proteins Deck (23)
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1

Three things that make up amino acids?

Amine group
Carboxylic acid group
Side chains - R

2

What is the mnemonic to remember essential amino acids?

PVT TIM HALL

3

Which essential AA is only essential in children?

Arginine

4

What are the essential AA?

Phenylalanine
Valine Tryptophan

Threonine
Isoleucine
Methionine

Histidine
Arginine
Lysine
Leucine

5

What are the acidic AA?

Glutamine
Glutamate
Aspartate
Asparagine

6

What are the basic AA?

Lys
His

7

First step in digestion?

Mechanical (chewing)

8

What is the role of HCl?

Denaturation of proteins

9

What protease hydrolyzes proteins in the stomach?

Pepsin

10

What releases proteases?

Pancreas
SI

11

What do G cells do?

Release gastrin in the stomach

12

What does gastrin do?

Stimulates the release of HCl from parietal cells

13

What deactivates pepsin?

Alkaline duodenum

14

How is pepsinogen activated?

It is partially activated by HCl and then auto-cleaves peptides off to become fully activated

15

What is the activation process of proteases released from the pancreas?

Enterokinase activates trypsinogen to trypsin
Trypsin activates chymotrypsinogen to chymotrypsin
Trypsin activates procarboxypeptidase to carboxypeptidase

16

Where do endopeptidases cleave?

At internal amide bonds

17

Where do ectopeptidases cleave?

At terminal amino acids of peptides

18

Where are carboxypeptidases cleave?

At C-terminal amino acids of peptides

19

Where do carboxypeptidases A and B cleave respectively?

A: neutral AA
B: basic AA

20

How are AA absorbed?

Active transport (mono, di, and tri but di and tri are broken down by enzymes in membrane)

21

How do AA move out of the villus epithelium?

Facilitated diffusion

22

What channel transports peptides into the villus?

PEPT1 (peptide transporter 1) along with an H+

23

What supplies the H+ for peptide absorption?

NHE sodium/hydrogen exchanger