Digestion

Question 1

What does amylase break down? How?

Answer 1

Starch into maltose by hydrolysing ester bonds
Polysaccharide -> disaccharide

Question 2

Where is amylase produced?

Answer 2

Salivary glands & Pancreus

Question 3

What is the function of membrane bound disaccharides?

Answer 3

Catalyse hydrolysis of ester bonds in disaccharides

Question 4

Where are membrane bound disaccharides?

Answer 4

Found in cell membranes of ileum epithelial cells

Question 5

What does sucrase catalyse?

Answer 5

Hydrolysis of ester bonds in sucrose

Question 6

What does lactase catalyse?

Answer 6

Hydrolysis of ester bonds in lactose

Question 7

Digestion order of carbohydrates in the body

Answer 7

Amylase produced by salivary glands & pancreas
Hydrolyse of starch to maltose
Dissaccharidases causing maltose to glucose
Transported by co transport proteins

Question 8

Why isn’t amylase in the stomach?

Answer 8

Too acidic

Question 9

Protein digestion process

Answer 9

Begins in the stomach
Into the duodenum
Finished in the ileum with co-transport proteins

Question 10

Conditions in the stomach

Answer 10

2pH - optimum for pepsid

Question 11

How does exopeptidase work?

Answer 11

Hydrolyse peptide bonds between amino acids at the end of a peptide chain

Question 12

How does endopeptidase work?

Answer 12

Hydrolyse peptide bonds between amino acids in the middle of a peptide chain

Question 13

How does membrane bound dipeptidase work?

Answer 13

Hydrolyse peptide ones in amino acids in dipeptidases

Question 14

Movement of lipase in the body

Answer 14

Produced in pancreus and secreted to small intestine

Question 15

What enzyme digest lipids?

Answer 15

Lipase - hydrolysis ester bonds

Question 16

Where are bile salts produced?

Answer 16

Liver

Question 17

Function of bile salts

Answer 17

Emulsification of lipids by forming small lipid droplets called micelles

Question 18

Benefit of micelle formation

Answer 18

Increase surface area (as more droplets) for lipase to act upon and form more E-S complexes

Question 19

What are micelles?

Answer 19

Vesicles of fatty acids, glycerol, monoglycerides and bile salts.

Question 20

Lipids: Physical digestion?

Answer 20

Emulsification & Micelle formation

Question 21

Lipids: Chemical digestion?

Answer 21

Lipase

Question 22

Ileum adaptations

Answer 22

Very long for increased time for diffusion and active transport of digestion products.

Lining has villi and microvilli for increased surface area.

Epithelial wall one cell thick so short diffusion path.

Rich blood supply to maintain a concentration gradient

Question 23

Why are micelles beneficial?

Answer 23

Deliver vesicles to the epithelial cell of ileum.

Make them soluble for diffusion.

Question 24

How do lipids diffuse through the ileum epithelial?

Answer 24

Micelles contain bile salts and fatty acids.

Micelles make monoglycerides and fatty acids soluble in water

Absorbed by diffusion

Triglycerides reformed in cells

Vesicles move to cell membrane

Question 25

Process in the Golgi body

Answer 25

Modifies triglycerides Combine triglycerides with proteins Packages for exocytosis.

Question 26

What type of proteins are co transport proteins?

Answer 26

Carrier

Question 27

Process of a carrier protein changing shape?

Answer 27

Molecule binds to complimentary receptor spanning cell membrane ATP binds to protein from inside the cell and is hydrolysed into ADP + Pi Causes carrier proteins to change shape and release molecule on other side. Pi molecule released and shape turns to original.

Question 28

Why is co-transport required for glucose or amino acids in the gut?

Answer 28

Usually more of these molecules in the epithelial cells then the lumen - incorrect concentration gradient

Question 29

Process of co-transport

Answer 29

Sodium ions actively transported out of epithelium into blood - reducing concentration gradient. Sodium ions diffuse from lumen down their concentration gradient into epithelial cells. Co transporter molecule where both sodium and the other molecule need to bind for a change of shape and transported against the conc gradient.

Question 30

What is active transport and its requirement?

Answer 30

Movement of substances from a low concentration to high concentration through a partially permeable. Requires ATP and carrier protein.

Question 31

What effects active transport?

Answer 31

ATP availiblity Number of carrier proteins