1. Digestion

Question 1

What is the problem with large biological molecules ?

Answer 1

Eg starch/ proteins

Too big t cross cell membrane.

Can’t be absorbed from the gut into blood

Question 2

What happens to these large molecules ?

Answer 2

Broken down into smaller molecules (glucose/ amino acids) which are capable of moving across membranes.

They can easily absorb into gut in blood to be transported around body for use in body cells

Question 3

HOW are these large molecules broken down ?

Answer 3

As they’re polymers they can be broken down into smaller molecules ( monomers) using hydrolysis reaction.

Question 4

Hydrolysis of carbohydrates

Answer 4

Disaccharides and monosaccharides

Question 5

Hydrolysis of fats

Answer 5

Fatty acids and monoglycetides

Question 6

Hydrolysis of proteins

Answer 6

Amino acids

Question 7

Function of digestive enzymes

Answer 7

Used to break down biological molecules in food.

Produced by specialised cells in digestive system.

Released in gut to mix with food. Thank

Question 8

Why are digestive enzymes significant?

Answer 8

Different enzymes needed to catalyse breakdown of different food molecules

Question 9

Function of amylase

Answer 9

Catalyses breakdown of starch.

It hydrolysis the glycosidic bonds in starch to produce maltose (disaccharide)

Question 10

Enzyme > polysaccharide > disaccharide

Amylase

Answer 10

Amylase > starch > maltose

Question 11

What is starch ?

Answer 11

Mixture of 2 polysaccharide chains

Each long chains of alpha glucose molecules

Question 12

Where is amylase produced

Answer 12

Salivary glands
Released into mouth

Pancreas
Released into small intestine

Question 13

What are membrane bound disaccharidases?

Answer 13

Enzymes

Attached to cell membrane of epithelial cells linking ileum

Help breakdown disaccharides into monosaccharides

This involves hydrolysis of glycosidic bonds

Question 14

Sucrase

Answer 14

Membrane bound disaccharidase

Catalyses breakdown of sucrose into the monosaccharides glucose fructose

Question 15

Maltase

Answer 15

Membrane bound disaccharidase

Catalyses breakdown of maltose into monosaccharides glucose and glucose

Question 16

Lactase

Answer 16

Membrane bound disaccharidase

Catalyses breakdown of lactose into monosaccharides glucose and galactose

Question 17

How to the monosaccharides transport across epithelial cell membrane ?

Answer 17

Via specific transporter proteins

Question 18

What bonds to carbohydrates break ?

Answer 18

Glycosidic

Question 19

Function of lipase enzymes

Answer 19

Catalyse breakdown of lipids into fatty acids and monoglycerides

Hydrolysis of water bond in lipids

Question 20

Where are lipases produced?

Answer 20

Pancreas

Released into small intestine where they act.

Question 21

Structure of monoglycetide molecule

Answer 21

Glycerol molecule

1 fatty acid attached

Question 22

Where are bile salts produced ?

Answer 22

Liver

Question 23

Function of bile salts

Answer 23

They emulsify lipids

Cause the lipids to form small droplets.

Several small droplets have a bigger surface area than a single large droplet (same volume)

This greatly increases surface area of lipid for lipase to work on

Question 24

What bonds are hydrolysed in breakdown of lipids?

Answer 24

Ester

Question 25

Once the lipid has been broken down by the lipase, monoglycerides and fatty acids stick with the bile salts, what structures form ?

Answer 25

Tiny structures Micelles These help with products of lipid digestion to be absorbed

Question 26

Peptidases are also called

Answer 26

Proteases

Question 27

What are proteins broken down into ?

Answer 27

Combination of different peptidases. Endopeptidases Exopeptidases Catalyse hydrolysis of proteins into amino acids breaking the peptide bonds between amino acid

Question 28

Function of endopeptidases

Answer 28

Hydrolysis peptide bonds within protein

Question 29

How to remember what endopeptidases do

Answer 29

enDopeptidases break bonds insiDe the proteins

Question 30

Example of endopeptidases

Answer 30

Pepsin Released in stomach Works in acidic conditions - hydrochloric acid

Question 31

Function of exopeptidases

Answer 31

Hydrolysise peptide bonds at the end of protein molecules Remove single amino acids

Question 32

What are dipeptidases?

Answer 32

Exopeptidases that work specially on dipeptides Separate 2 amino acids that make up the dipeptide by hydrolysing peptide bonds. Located on cell surface membrane of epithelial cells in small intestine