digestion and absorption

Question 1

Which saccharide bonds does amylase breakdown?

Answer 1

alpha 1-4

Question 2

What is a glycocalyx?

Answer 2

glycoprotein layer on the microvilli

Question 3

Where is there NO carbohydrate breakdown?

Answer 3

The stomach

Question 4

Name the 3 brush border enzymes on the intestinal mucosa

Answer 4

Lactase, Maltase, Sucrase

Question 5

What is alpha dextrin?

Answer 5

an oligosaccharide that contains alpha 1-4 and 1-6 bonds

Question 6

Name two enzymes that can break down alpha 1-6 bonds

Answer 6

isomaltase and glucoamylase

Question 7

Which three disaccharides are broken down by just one specific enzyme?

Answer 7

lactose, trehalose, sucrose

Question 8

What is the rate limiting step of glucose uptake?

Answer 8

absorption

Question 9

Which transporter does fructose use?

Answer 9

GLUT5 - apical mem

GLUT2 - basolateral mem

Question 10

Name two facilitated diffusion transporters

Answer 10

GLUT2 and GLUT5

Question 11

Where is the main site of protein digestion?

Answer 11

Duodenum

Question 12

What does enterokinase do?

Answer 12

activate trypsinogen to trypsin

Question 13

what are endopeptidases?

Answer 13

enzymes that split polypeptides

Question 14

What are exopeptidases?

Answer 14

enzymes that split end terminal amino acids

Question 15

How are proteins absorbed?

Answer 15

Via PepT1 on apical mem. This co-transports H+ and the peptide into the cell. Na+ / K+ ATPase required. Then Na+ / H+ exchanger on apical membrane required. H+ gradient used to transport peptide.

Question 16

What is the function of bile?

Answer 16

Help to solubilise fat and cholesterol

Question 17

Why do fatty acids head for the smooth ER after diffusing across the cell?

Answer 17

in order to reform into triglycerides to maintain the concentration gradient allowing the free diffusion of the fatty acids into the cell.

Question 18

How do chylomicrons absorb into the bloodstream?

Answer 18

Via the lacteals of the lymphatic system. Large gaps between lacteals (lymphatic capillary).

Question 19

What happens in glucose-galactose malabsorption syndrome?

Answer 19

Mutation in SGLT1 transporter, poor uptake. Excess glucose and galactose in lumen of the intestine. Diarrhoea, flatulence, muscle wasting. give lactose instead (uses different transporter)

Question 20

What is lactose intolerance?

Answer 20

deficiency or dysfunctional lactase

Question 21

What is hartnup’s disease?

Answer 21

defect in transport of amino acids, appear in urine. Kidney problems

Question 22

What is gluten enteropathy?

Answer 22

flattened microvilli, poor absorption of gluten. Large amount of fat excreted.