Protein, Carbohydrate & Fat Absorption

Question 1

What partially breaks down proteins in the stomach?

Answer 1

Pepsin

Question 2

What further breaks down proteins in the small intestine?

Answer 2

Trypsin

Chymotrypsin

Question 3

What are trypsin and Chymotrypsin?

Answer 3

Pancreatic proteases

Question 4

What peptidase helps in protein breakdown?

Answer 4

Carboxypeptidass

Question 5

What is located on the luminal membrane that aids protein breakdown?

Answer 5

Aminopeptidases

Question 6

What do carboxypeptidases do?

Answer 6

Remove the amino acids from the carboxyl end

Question 7

What do Aminopeptidases do?

Answer 7

Remove amino acids from the amino end

Question 8

Why passes into the cell along with amino acids?

Answer 8

Na+

Question 9

What two transporters are there for carbohydrate absorption?

Answer 9

Glucose transporter (GLUT) 
Sodium-glucose transporter (SGLT)

Question 10

What is the name of the membrane on the luminal side?

Answer 10

Apical membrane

Question 11

What is the name of the membrane on the blood side of the epithelium?

Answer 11

Baso lateral membrane

Question 12

What is transported by the GLUT in the small intestine?

Answer 12

Fructose

It is a GLUT5

Question 13

What is transported by the SGLT in the small intestines?

Answer 13

Glucose
Galactose
Na+

Question 14

Where does the majority of carbohydrate absorption take place?

Answer 14

First 20%

Question 15

What happens to cellulose?

Answer 15

It is transported to the large intestine where it is partially metabolised by bacteria

Question 16

What is transported across the baso lateral membrane in protein absorption?

Answer 16

K+ out
K+ in & Na+ out (ATP transporter)
Amino acids

Question 17

What crosses the baso lateral membrane in carbohydrate absorption?

Answer 17

K+ out
K+ in & Na+ out (ATP transporter)
Fructose, glucose & galactose out

Question 18

Does breakdown of proteins to amino acids occur completely in the lumen before entering the enterocyte?

Answer 18

No - some small peptides pass into the enterocyte and break down to amino acids

Question 19

What happens to the fat droplets in the first step of fat absorption?

Answer 19

They are emulsified

Question 20

What is used to emulsify the fat droplets?

Answer 20

Bile salts

Question 21

Why do bile salts emulsify fat droplets?

Answer 21

They have a hydrophobic part and a hydrophilic part. The hydrophobic part goes into the fat droplets and the hydrophilic part sticks out. This breaks up the fat droplet

Question 22

What is the name of the emulsified fat droplets?

Answer 22

Micelles

Question 23

What breaks down micelles into free fatty acids and monoglyceeides?

Answer 23

Pancreatic lipase

Question 24

What happens to the free molecules of fatty acids and monoglycerides?

Answer 24

They diffuse into the enterocytes and into the endoplasmic reticulum

Here they combine to form triglycerides and combine with cholesterol and phospholipids

They collectively form a chylomicron

The chylomicron then passes out the cell into the lymphatics where it is transported to cells

Question 25

What is the mechanism in which chylomicrons pass out of the enterocytes?

Answer 25

Exocytosis