Enzymes

Question 1

What is a catalyst?

Answer 1

A catalyst is a substance which increases the speed of a reaction, without being used up

Question 2

Explain the lock and key theory.

Answer 2

The active site of an enzyme is specific to a particular substrate

Question 3

What are the Effecting Factors of enzymes?

Answer 3

Temperature

PH level

Question 4

Explain what happens when an enzyme denatures due to temperature.

Answer 4

The bond holding the enzyme together will break and the shape of the active site will change and the substrate won’t fit into it anymore.

Question 5

Enzymatic Reactions

Answer 5

amylase breaks down starch
iodine is a simple way to detect starch
browny-orangey to blue-black

Question 6

Investigating Enzymatic Reaction 2.0

Answer 6

• place 1 cm cubed of amylase solution and 1 cm cubed of buffer solution with a PH of 5 into a boiling tube and place into the water
• add 5 cm cubed of starch solution into the boiling tube
• mix the solution and investigate the amount of time it took for amylase to breakdown the starch
• if colour change starch is present
• repeat with different PH of buffer solution and see how it affects the time of breakdown of starch
• control variables ( concentration and volume of amylase solution )

Question 7

What is Rate?

Answer 7

a measure of how much something changes over time

Question 8

How do you investigate rate of reaction?

Answer 8

Rate = 1000/time

The unit of rate is s (to the power of) -1

Question 9

Why do digestive enzymes break down big molecules?

Answer 9

too big to pass through the walls of the digestive system so they are broken down into smaller soluble molecules that pass easily, allowing them to be absorbed into the bloodstream

• sugar
• amino acids
• fatty acids
• glycerol

Question 10

Carbohydrases / Amylase

Answer 10

converts carbs into sugar e.g maltose, dextrine

made in three places

• salivary gland
• pancreas
• small intestine

Question 11

Protease

Answer 11

protein into amino acids

made in three places

• stomach
• pancreas
• small intestine

Question 12

Lipase

Answer 12

lipids into glycerol & fatty acids

made in two places

• pancreas
• small intestine

Question 13

Describe Bile Role

Answer 13

produced in liver, stored in gall bladder before released into small intestine

neutralises stomach acids
- hydrochloric acid makes the pH too acidic in the small intestine so bile (alkaline) neutralise it.

emulsifies fats
- breaks the fats into tiny droplets and give a bigger surface area for lipase to work which makes digestion faster.

Question 14

Enzymes Function in Digestive System

Answer 14

Salivary gland- amylase is produced
Liver- where bile is produced
Gall bladder- where bile is stored
Large intestine- excess water is absorbed from food
Small intestine- where food is absorbed and taken into bloodstream
Pancreas- enzymes are produced
Stomach- produces hydrochloric acid to kill bacteria and to give right pH for protease to work
Rectum- where faeces is made and stored