Carbs and protein

Question 1

Sucrose

Answer 1

glucose and fructose

Question 2

Lactose

Answer 2

Glucse and galactose

Question 3

Salivary alpha amylase

Answer 3

secrete in the enzymatically active form
initiates starch digestion
inactivated by gastric acid

Question 4

Pancreatic alpha amylase

Answer 4

completes starch digestion
stimulated by CCK
cannot digest terminal branch points

Question 5

Membrane digestion

Answer 5

Step 2 after amylases
brush border oligosaccharideases

proximal jejunum

Question 6

Lactase

Answer 6

membrane bound oligosaccharideases

digest lactose into glucose and galactose

decreased expression after infancy

Question 7

Sucrase-isomaltase

Answer 7

membrane bound oligosaccharideases

cleaves sucrase and splits branch point

**essential for breaking down polysccharides with branch points

Question 8

Na/Glucose transporter (SGLT1)

Answer 8

responsible for glucose and galactose uptake

secondary active transport (driven my Na/K ATPase

Question 9

GLUT5

Answer 9

responsible for fructose uptake in jejunum

facilitated diffusion

DEPENDENT OF CONCENTRATION OF FRUCTOSE

Question 10

GLUT2

Answer 10

transport of all three monos into the interstitium

at BL membrane

facilitated diffusion= concentration dependent

Question 11

Lactose intolerance

Answer 11

most common in non-whites

due to epigeneitic down-regulation of lactase

cramps, diarrhea, flatus

Gut bacteria then break it down—>short chain FAs—>osmotic diarrhea

H+ is also absorbed–>H breath test

Question 12

Glucose-Galactose absorption

Answer 12

defect in SGLT= no glucose or galactose uptake

—>osmotic diarrhea with decreased Na reabs via SGLT

tx= glu gal and lactose free diet =fructose based diet

Question 13

Gastric protease

Answer 13

secreted as a proenzyme

pepsinogen—>pepsin =endopeptidase

Question 14

Pancreatic protease

Answer 14

secreted as proenzymes

trypsinogen—>trypsin

trypsin then continues to autoacitvate and activate other enzymes

Question 15

chymotrypsinogen

Answer 15

activated by trypsin

chymotrypsin

endo

Question 16

proelastase

Answer 16

activated by trypsin to elastase

endo

Question 17

procarboxypeptidase A and B

Answer 17

activated by trypsin
to carboxypeptidase A and B

exo

Question 18

whole protein absorption: children

Answer 18

occurs in the neonate

passes Igs from mother to child
closure associated with corticosteriod use

Question 19

whole protein absorption in adults

Answer 19

only small amounts occur 
1) endycytoses into lysosomes by enterocytes 
2) M cells 
package proteins as antigens 
important for mucosal immunity

Question 20

Oligopeptide absorption

Answer 20

most absorbed as single AA, with small amts as di-, tri- or tetrapeptides

Question 21

PepT1 H+ oligopeptide cotransporter

Answer 21

kinetic advantage over AA transporters in that substrate enters faster

actively driven by H+ Na+ gradient Created by Na/K ATPase and Na/H antiporter

Question 22

Hartnup disease

Answer 22

AR disorder

defect in apical transport of neutral AA

sx= pellagra, ataxia, psych abnormalities

tx= high protein diet allows oligos to pass thru PEPt1

Question 23

Cystinuria

Answer 23

AR disorder

defect in apical transport of basic AA and cyseine

sx= kidney stones

Question 24

apical membrane single AA abs

Answer 24

either Na/K ATPase dependent=neutral AA

or independent= basic AA and cysteine

Question 25

BL membrane transport of single AA

Answer 25

bidirectional

Exit= Na independent 
Entrance= Na dependent, for enterocyte  nutrition and growth