B2 Absorption of digested food

Question 1

Describe how glucose is absorbed from the lumen of the small intestine into the blood.

Answer 1

Sodium ions actively transported out of epithelium cell.
Using sodium/potassium pump
Maintains a low concentration of sodium ions inside epithelium cell.
Sodium ion and glucose co-transported from small intestine into epithelial cell down the concentration gradient for sodium ions.
Glucose the passes into blood by facilitated diffusion

Question 2

What happens to triglycerides which have reformed in the endoplasmic reticulum of the small intestine epithelium?

Answer 2

Transferred to Golgi apparatus and combined with cholesterol and lipoprotein
To form Chylomicrons

Question 3

How are the villi adapted to optimise the absorption of digested food?

Answer 3

Large surface area for diffusion
Microvilli further increase surface area
Very thin walls so short diffusion distance
Many capillaries so maintains the concentration gradient.

Question 4

What is a lacteal?

Answer 4

Lymphatic capillary in the centre of each villus

Question 5

Where are the products of digestion absorbed?

Answer 5

Small intestine/ileum

Question 6

Glucose and amino acids are absorbed by ……

Answer 6

Cotransport

Question 7

What happens to monoglycerides and fatty acids after they enter the epithelium cell of the small intestine

Answer 7

Transported to endoplasmic reticulum where they are recombined into triglycerides

Question 8

What happens to monoglycerides and fatty acids after they enter the epithelium cell of the small intestine

Answer 8

Transported to endoplasmic reticulum
Condensed to form triglycerides

Question 9

How do monoglycerides and fatty acids enter the epithelium cell of the ileum

Answer 9

Simple diffusion

Question 10

Bile salts emulsify fatty acids into smaller structures called …..

Answer 10

Micelles

Question 11

What is the function of the Golgi apparatus in lipid absorption/

Answer 11

Triglycerides associate with cholesterol and lipoproteins

Question 12

What is the function of the Golgi apparatus in lipid absorption?

Answer 12

Triglycerides associate with cholesterol and lipoproteins
To form chylomicron

Question 13

Name the type of transport used to move sodium ions out of the epithelium cells of the small intestine

Answer 13

Co-transport - sodium and potassium ions transported in opposite directions.
Active transport -

Question 14

Name the three chemicals that bind to a glucose co-transporter carrier protein

Answer 14

Sodium ion
Glucose
ATP

Question 15

How many different co-transporter carrier proteins are need to transport all the different amino acids into the epithelium cells of the the small intestine

Answer 15

One for each type of amino acid ie 20