Carb and Protein Digestion Module (Quiz)

Question 1

most dietary carbohydrates are

Answer 1

• large polysaccharides

- disaccharides

Question 2

4 different forms of carbohydrates we consume

Answer 2

• starch
• sucrose
• lactose
• maltose

Question 3

which two polysaccharides compose starch

Answer 3

• amylose

- amylopectin

Question 4

both amylose and amylopectin are ______ polymers

Answer 4

• glucose

Question 5

luminal digestion of starch begins in the mouth with the action of _______ and ends in the small intestine via action of ________

Answer 5

• alpha-amylase

- pancreatic alpha amylase

Question 6

salivary and pancreatic amylase have optimum activities near _____ pH

Answer 6

• neutral

Question 7

salivary amylase destroyed by ________

Answer 7

• acid in the stomach

Question 8

where does most digestion of starch occur

Answer 8

• small intestine

Question 9

role of pancreatic alpha-amylase

Answer 9

• hydrolyze alpha 1,4 bonds of amylose and amylopectin into alpha-limit dextrins

Question 10

final digestive step of carbs occurs where

what happens?

Answer 10

• intestinal brush border
• intestinal brush border enzymes cleave oligosaccharides and disaccharide into glucose, fructose, and galactose which can be absorbed across the brush border

Question 11

rate limiting step in sugar assimilation

Answer 11

• absorption of monosaccharides across brush border

Question 12

under normal circumstances the majority of sugar assimilation is complete by the time it reaches ________

Answer 12

• proximal jejunum

Question 13

do we have a cellulase capable of digestiing beta glucose bonds like are found in cellulose

Answer 13

• no

Question 14

routes of absorption of carbohydrates

Answer 14

• SGLT-1
• GLUT-5
• GLUT-2

Question 15

SGLT-1 transmembrane protein mediates transfer of __________ cross apical membrane.

occurs via ___________ transport

also allows transport of ______ and _____

Answer 15

• sodium and glucose
• sodium dependent secondary active transport
• galactose and glucose

Question 16

unlike the SGLT-1 transmembrane protein which requires active transport, the GLUT-5 and GLUT-2 transmembrane proteins work via ___________

Answer 16

• passive diffusion

Question 17

___________ facilitates the transport of fructose across the apical membrane into the cytosol

Answer 17

• GLUT-5

Question 18

_________ allows for diffusion of glucose and galactose across basolateral membrane into the portal circulation

Answer 18

• GLUT-2

Question 19

apical transport is _________ driven

Answer 19

• energy driven

Question 20

the intestine is capable of transporting not just single amino acids but also _________

Answer 20

• short oligomers

Question 21

the final stage of protein digestion takes place where?

Answer 21

• cytosol of the enterocyte

Question 22

luminal digestion

proteolytic digestive enzymes are released in ______ forms first

Answer 22

• inactive zymogens

Question 23

how does pepsinogen become activated into pepsin

Answer 23

• secreted into low pH environment in response to a meal

- undergoes autocatalytic cleavage

Question 24

pepsins cleave dietary proteins at ______ amino acids

Answer 24

• neutral

Question 25

pepsins inactivated at pHs ______

Answer 25

above 4.5

Question 26

majority of products that come from proteolytic action of pepsin

Answer 26

- large non-absorbable peptides | - few free amino acids

Question 27

the majority of proteolysis occurs where

Answer 27

- small intestinal lumen

Question 28

classification of pancreatic proteases

Answer 28

- endopeptidases | - exopeptidases

Question 29

endopeptidases cleave proteins and peptides at _______ bonds whereas exopeptidases cleave at _________

Answer 29

- internal amide bond (INTERNAL IS IMPORTANT) | - terminal amio acid (TERMINAL IS IMPORTANT)

Question 30

endopeptidases include:

Answer 30

- trypsin - chymotrypsin - elastase

Question 31

exopeptidases include:

Answer 31

- carboxypeptidase A and B

Question 32

inactive zymogens converted into active forms via action of ___________

Answer 32

- trypsin

Question 33

trypsin is produced as a result of cleavage by trypsinogen via enzyme _________

Answer 33

- enterokinase

Question 34

enterokinase expressed on apical membrane of ______ epithelial cells

Answer 34

- duodenal

Question 35

which proteins can be absorbed by carriers

Answer 35

- di and tri peptides | - free amino acids

Question 36

small peptides are absorbed by a carrier with a _______ specificity

Answer 36

- broad

Question 37

absorption of peptides is __________ of the Na+ gradient is stimulated by an inwardly directed ______ gradient maintained via an apical __________ exchanger absorption of free amino acids is _______ on the Na+ gradient

Answer 37

- independent - H+ - sodium-hydrogen - dependent

Question 38

peptides that enter enterocytes are further hydrolyzed by _______ to free amino acids

Answer 38

- cytoplasmic peptidases

Question 39

how do free amino acids get into portal circulation

Answer 39

- carrier-mediated | - diffuse across basolateral membrane

Question 40

lactose breaks into

Answer 40

- glucose | - galactose