Digestion & Absorption

Question 1

Where is amylase produced and secreted?

Answer 1

• produced in salivary glands and pancreas

- pancreas secretes amylase into small intestine

Question 2

What is the function of amylase?

Answer 2

To hydrolyse starch into maltose

Question 3

What are membrane-bound disaccharides?

Answer 3

• enzymes that hydrolyse disaccharides to monosaccharides

- maltase, sucrase & lactase

Question 4

Where are membrane-bound disaccharides found?

Answer 4

Present in the membrane of the small intestine

Question 5

What is the function of lipase?

Answer 5

To hydrolyse lipids to monoglycerides + fatty acids

Question 6

Where are lipases found?

Answer 6

In the small intestine

Question 7

What are some adaptations in the break down of lipids?

Answer 7

• bile salts emulsify lipids so they have a larger surface area for hydrolysis
• products can remain associated with bile salts to form micelles
• micelles travel to the ileum + are broken down when in contact with epithelium so products diffuse straight into epithelium

Question 8

What is the function of protease?

Answer 8

To hydrolyse proteins into amino acids

Question 9

What are the 3 types of proteases?

Answer 9

Endopeptidases
Exopeptidases
Membrane-bound dipeptidases

Question 10

What are some examples of endopeptidases?

Answer 10

Trypsin, chymotrypsin + pepsin

Question 11

What do endopeptidases do?

Answer 11

Hydrolyse peptide bonds in the middle region of the polypeptide chain

Question 12

What do exopeptidases do?

Answer 12

Hydrolyse emptied bonds on terminal amino acids

Question 13

What do membrane-bound dipeptidases do?

Answer 13

Hydrolyse dipeptidases into 2 amino acids

Question 14

What is the sodium-potassium pump

Answer 14

A protein pump that transports sodium ions out of the cell + potassium ions into the cell

Question 15

What does the sodium-potassium pump maintain?

Answer 15

• higher concentration of Na ions outside the cell
• higher concentration of K ions inside the cell
• also helps stabilise cells membrane potential

Question 16

What is the basic cycle of the Na-K pump?

Answer 16

Uses ATP to transport Na ions + K ions across the cell membrane

Question 17

What is the first step of the sodium-potassium pump?

Answer 17

• 3 Na ions bind to the pump
• 2 K ions are released from the pump
• ATP binds to the pump releasing a phosphate ion to create ADP
• causes a conformational change

Question 18

What is the second step in the sodium-potassium pump cycle?

Answer 18

• Na ions are released into extra cellular fluid
• at the same time the pump binds 2 K ions
• prompts another conformational change so pump returns to its original configuration