Case 3 - nutrient absorption

Question 1

what are proteins broken down into and where

Answer 1

broken down into amino acids, di peptides and tri peptides, by the stomach, pancreas and brush border

Question 2

what can all of these be absorbed by

Answer 2

the gut

Question 3

what are polysaccharides broken down into

Answer 3

broken down into monosaccharides by saliva, pancreas and the brush border

Question 4

what breaks down disaccharides

Answer 4

brush border

Question 5

what are examples of polysaccharides

Answer 5

glycogen and starch

Question 6

what are triglycerides broken down into and where

Answer 6

broken down into free fatty acids, and monoglycerides, but the stomach, pancreas and bile salts

Question 7

what is incomplete absorption

Answer 7

malabsorption

Question 8

what Is the potential absorption method for lipids

Answer 8

simple diffusion

Question 9

what is the absorption method for amino acids and sugars

Answer 9

carrier mediated;
- secondary active
- facilitated diffusion

Question 10

what is the absorption method for vitamin B12, intrinsic factor and cholesterol

Answer 10

receptor mediated endocyotisis

Question 11

where are the major sites of absorption

Answer 11

duodenum and jejunum

Question 12

where is there limited diffusion

Answer 12

mouth, oesophagus, stomach

Question 13

what is absorbed in the ileum

Answer 13

Vit.B12, bile salts and K+

Question 14

what is absorbed in the colon

Answer 14

Na+, some H20 and short chain fatty acids

Question 15

why are the mouth and rectum not used really

Answer 15

they go straight into the blood stream to the heart

Question 16

what is the total area of the small intestine

Answer 16

200m squared

Question 17

why is the surface area of the small intestine so big

Answer 17

foldings in the wall
villi
microvilli - brush border

Question 18

why else is the small intestine so important

Answer 18

polarised expression of transport proteins

Question 19

what are the carbohydrates absorbed

Answer 19

glucose, galactose, and fructose

Question 20

what is SGLT1 and where is it found. what carb does it absorb

Answer 20

secondary active transport

found on apical lumen side

it is for glucose

Question 21

what is GLUT5 and where is it found. what carb does it absorb

Answer 21

facilitated diffusion - found on apical (lumen) side

for fructose

Question 22

what is GLUT2 and where is it found. what carb is it for

Answer 22

for facilitated diffusion

found on other side of the membrane

for fructose

Question 23

describe secondary active transport

Answer 23

against concentration gradient. energy derived from Na+ gradient created by Na+ pump

Question 24

what is the Na+ pump

Answer 24

primary active transport

Question 25

what is glucose-galactose malabsorption syndrome

Answer 25

genetic disease
mutated version of SGLT1 - no absorption
severe and potentially fatal diarrhoea in infants

Question 26

what is the treatment for Glucose-galactose malabsorption syndrome

Answer 26

avoid glucose and galactose

Question 27

what are 50% of amino acids absorbed by

Answer 27

PEPT1 as di and tri peptides

Question 28

where is it hydrolysed and what to

Answer 28

to amino acid in enterocyte

Question 29

what is the other 50% absorbed by

Answer 29

Xag- : anionic (aspartate, glutamate)
B0 : neutral a.a
B0+ : cationic and cystine
PAT1 : proline

Question 30

what are all the transporters all part of

Answer 30

the SLC superfamily

Question 31

amino acids use what kind of active transport

Answer 31

secondary active transport

Question 32

what does PepT1 use

Answer 32

uses proton gradient to carry peptides and co-transports H+

Question 33

what does B0 use

Answer 33

uses sodium cotransport, sodium and alanine moving across the cell membrane

Question 34

what does Xag- use

Answer 34

uses 3 ions; sodium and glutamate going in and potassium going out

Question 35

what rare genetic diseases cause appearance of amino acids in urine

Answer 35

Hartnup disease (B0)
bystinuria
Bo+ - kidney stones