Nutrient Digestion and Absorption

Question 1

what form can the body absorb carbohydrates in?

Answer 1

hexose sugars

Question 2

what are the hexose sugars?

Answer 2

glucose, galactose, fructose

Question 3

what are disaccharides made up of and what links them?

Answer 3

two monosaccharides linked together by a glycosidic bond

Question 4

where are the enzymes which break down disaccharides?

Answer 4

brush border of small intestine

Question 5

what is lactose made up of?

Answer 5

glucose + galactose

Question 6

what is sucrose made up of?

Answer 6

glucose + fructose

Question 7

what is maltose made up of?

Answer 7

glucose + glucose

Question 8

which polysaccharide cannot be enzymaticallly digested by vertebrates?

Answer 8

cellulose

Question 9

how do vertebrates digest cellulose?

Answer 9

bacterial production of cellulose

Question 10

what form do plants store glucose in?

Answer 10

starch

Question 11

what form does a-amylose take?

Answer 11

glucose linked in straight chains

Question 12

what form does amylopectin take?

Answer 12

highly branched glucose chains

Question 13

what type of bond links glucose monomers in starch and glycogen?

Answer 13

a-1,4-glycosidic bond

Question 14

what is the animal storage form of glucose?

Answer 14

glycogen

Question 15

which enzyme is required to break down b-1,4-glycosidic bonds?

Answer 15

cellulase

Question 16

which enzyme is required to break down a-1,4-glycosidic bonds?

Answer 16

amylase

Question 17

what separates the apical membrane of columnar cells from the basolateral membrane?

Answer 17

tight junctions

Question 18

what is a normal blood glucose level?

Answer 18

5mM

Question 19

which transporter allows glucose to cross the apical membrane?

Answer 19

SGLT1 –> sodium coupled glucose transporter

Question 20

which transporter allows glucose to cross the basolateral membrane?

Answer 20

GLUT-2

Question 21

which transporter allows fructose to cross the apical membrane?

Answer 21

GLUT-5

Question 22

which transporter allows fructose to cross the basolateral membrane?

Answer 22

GLUT-2 (same as glucose)

Question 23

structurally, what are proteins?

Answer 23

polymers of amino acids linked together by peptide bonds

Question 24

what are small proteins of 3-10 amino acids in length known as?

Answer 24

peptides

Question 25

which enzymes are required to hydrolyse peptide bonds?

Answer 25

proteases or peptidases

Question 26

how do endopeptidases act?

Answer 26

act in the middle of the chain, splitting into two smaller peptides.. etc

Question 27

how do exopeptidases act?

Answer 27

act near the amino-terminal or carboxy-terminal ends to shorten the chain

Question 28

which transporter allows amino acids to cross the apical membrane?

Answer 28

SAAT1 --> sodium coupled amino acid transporter

Question 29

what causes the acidic microclimate close to the apical membrane?

Answer 29

NHE3 --> sodium hydrogen exchange - creates high conc of hydrogen ions on the surface

Question 30

why is it beneficial to have an acidic microclimate near the apical membrane?

Answer 30

PepT1 transporter transports dipeptide with a hydrogen ion across the apical membrane