GI5

Question 1

what are three things that amplifies surface area?

Answer 1

• folds
• villi and crypts
• microvilli

Question 2

the epithelium lining in the small intestine is ____

Answer 2

leaky

Question 3

what part of the crypt contains digestive enzymes?

Answer 3

glycocalyx

Question 4

what cells of the crypt secrete antimicrobial peptides?

Answer 4

paneth cells

Question 5

are there stem cells in the crypt?

Answer 5

yes

Question 6

what layer presents a barrier to diffusion in the gut?

Answer 6

unstirred layer

Question 7

what two things make up the unstirred layer?

Answer 7

• glycocalyx layer

- mucous layer

Question 8

nutrients must pas though what layer in order to be absorbed?

Answer 8

unstirred layer

Question 9

what is the overarching goal of digestion?

Answer 9

-reduce particle size to enable absorption

Question 10

what is hydroysis?

Answer 10

splitting of a chemical bond by the insertion of water

Question 11

what type of bonds are in carbs?

Answer 11

glycosidic bonds

Question 12

what type of bonds are in proteins?

Answer 12

peptide bonds

Question 13

what type of bonds are in fats?

Answer 13

ester bond

Question 14

what type of bonds are in nucleic acids?

Answer 14

phosphodiester bonds

Question 15

what do digestive enzymes do?

Answer 15

catalyze hydrolysis

Question 16

what phase are proteins and starch hydrolyzed?

Answer 16

luminal phase, active withing the gut lumen

Question 17

what phase are polysaccharides and peptides hydrolyzed?

Answer 17

membranous phase, active at the gut epithelial surface

Question 18

where is the enzyme origin for luminal phase?

Answer 18

• salivary glands
• gastric glands
• pancreas

Question 19

where is the enzyme origin for membranous phase?

Answer 19

-apical membrane of enterocytes

Question 20

what is starch comprised of?

Answer 20

amylose and amylopectin

Question 21

is amylose straight or branched?

Answer 21

straight

Question 22

is amylopectin straight or branched?

Answer 22

branched

Question 23

which peptidase can only cleave in the middle of a protein, and cannot release free amino acids?

Answer 23

endopeptidases

Question 24

which peptidase can cleave at the ends and release individual AAs?

Answer 24

exopeptidase

Question 25

what is a key pancreatic zymogen activator?

Answer 25

trypsin

Question 26

at what pH does pepsin have maximal activity?

Answer 26

pH 1-3

Question 27

T/F: the stomach is essential for digestion and survival.

Answer 27

false

Question 28

lactose breaks down into:

Answer 28

glucose and galactose

Question 29

sucrose breaks down into

Answer 29

glucose and fructose

Question 30

starch breaks down into

Answer 30

glucose

Question 31

GLUT5 carriers what?

Answer 31

glucose and fructose

Question 32

SGLT1 carries what?

Answer 32

glucose and galactose

Question 33

enterocytes absorb short peptides and free AAs but release only ___ ___ ___ into the blood.

Answer 33

-free amino acids

Question 34

many uptake uptake mechanisms are coupled to ____ movement.

Answer 34

Na+

Question 35

what is the first step of the absorptive process?

Answer 35

luminal uptake