wk 1 8 physiology of digestion and absorption 2

Question 1

what must all dietary carbohydrates be converted to for absorption

Answer 1

monosaccharides

Question 2

which enzyme breaks starch down to oligosaccharides

Answer 2

alpha-amylase

Question 3

what aspect of alpha-amylase means that it cannot produce glucose

Answer 3

cannot cleave terminal alpha1,4-linkages or ones adjacent to branch points (only internal) means that there will be atleast a maltose left at end (depends on strucutre)
also cannot cleave alpha,1-6 linkages at branch points

Question 4

lactase used to

Answer 4

break down lactose to glucose and galactose

Question 5

purpose of sucrase

Answer 5

hydrolysis of sucrose - gluocse and fructose

Question 6

lactose intolerance is due to

Answer 6

lactase insufficiency

Question 7

other than primary hypolactasia (lack of lactase persistence allele) what can cause lactose intolerance

Answer 7

damage/ infection of proximal small intestine

Question 8

consequences of hypolactasia

Answer 8

CO2, hydrogen and methane 
causes:
bloating
abdominal pain 
flatulence 
acidification of colo  and increased osmotic load - loose stools

Question 9

where does the absorption of glucose, galactose and fructose occur (final products of carbohy digestion)

Answer 9

duodenum and jejunum

Question 10

SLGT2 absorbs

Answer 10

glucose and galactose

Question 11

exit for all monosaccharides is mediated by facillitated diffusion by, how does fructose exit?

Answer 11

GLUT2

facilitated diffusion mediated by GLUT5

Question 12

first step of SGLT1 is the binding of Na+, what does this cause

Answer 12

increase affinity for glucose

Question 13

number of Na+ required for SGLT1

Answer 13

2

Question 14

what begins protein denaturation

Answer 14

HCl

Question 15

which enzyme cleaves protein into peptides

Answer 15

pepsin

Question 16

product of procarboxypeptidase A and B

Answer 16

single amino acids

Question 17

which of the proteases secreted in the duodenum are endopeptidase (activated form)

Answer 17

trypsin
chymotrypsin
elastase

Question 18

hartnup disease is due to a dysfunction of

Answer 18

a Na+-dependent co-transporter (mediates uphill movement of neutral amino acids)
at the brush border

Question 19

cystinuria is a dysfunction due to

Answer 19

uptake of cationic amino acids at the brush border

Question 20

what does peptidase at the brush border hydrolyse

Answer 20

olgiopeptides to amino peptides

Question 21

PepT1 is a co-transporter which transports

Answer 21

olgiopeptides acrosd the apical membrane

Question 22

how do amino acids exit the basolateral membrane

Answer 22

several Na+-independent transporters