B2.5 - Enzymes

Question 1

What are proteins made of?

Answer 1

Protein molecules are made up of long chains of amino acids. These proteins are folded to produce specific shapes, which determine their job.

Question 2

What happens when proteins are folded?

Answer 2

Proteins are folded to produce specific shapes, which determine their job.

Question 3

What happens when amino acids are digested?

Answer 3

We release amino acids during digestion.

Ribosomes reconstruct amino acids into proteins that we need, joined in different orders.

Question 4

What are some functions of proteins?

Answer 4

Structural components of tissues (muscle)

Hormones (insulin)

Antibodies (to stick to bacteria)

Catalysts

Question 5

What are enzymes?

Answer 5

Enzymes are biological catalysts made up of proteins.

Question 6

What is a catalyst?

Answer 6

A catalyst is a substance which increases the speed of a reaction without being changed or used up in a reaction.

Question 7

What is the active site of an enzyme?

Answer 7

The space in an enzyme where the substance can fit.

Question 8

What is the substrate?

Answer 8

The substance on which the enzyme acts - it binds to the active site.

Question 9

What is the “lock and key” model?

Answer 9

Enzymes can only bind to one substrate and ergo can only catalyse one specific reaction. Any other shapes won’t fit - like a lock and key.

Question 10

How are products produced by enzymes?

Answer 10

Mechanical stress

Question 11

What is the term used to refer to an enzyme and a substrate placed together?

Answer 11

An enzyme substrate complex

Question 12

Why do enzymes work best at a higher temperature?

Answer 12

The higher temperature means that the molecules move around more quickly and collide with each other more frequently and with more energy.

Question 13

What happens if the temperature of an enzyme is too high?

Answer 13

The enzyme’s shape changes and cannot catalyse its reaction - it has denatured.

Question 14

What happens if the pH of an enzyme is not optimum?

Answer 14

If the enzyme is too acidic or two alkaline for the enzyme then the active site changes and the enzyme becomes denatured.

Question 15

Where are digestive enzymes produced and where do they go?

Answer 15

Digestive enzymes are produced by the specialised cells in glands and in the lining of the gut.

The enzymes pass out of the cells and come into contact with the food.

Question 16

What is digestion?

Answer 16

Digestion is the breaking down of large, insoluble molecules into smaller, soluble molecules.

Question 17

What molecules are too big for absorption?

Answer 17

Starch, proteins, and fats are too big to pass through the walls of the digestive system.

Question 18

What molecules are right for absorption?

Answer 18

Sugars, amino acids, glycerol, and fatty acids are small enough to pass through the walls.

Question 19

Where is amylase made?

Answer 19

The salivary glands, pancreas, small intestine

Question 20

What does amylase catalyse?

Answer 20

Digestion of starch into sugars

Question 21

Where does amylase work?

Answer 21

Small intestine and mouth

Question 22

What is starch?

Answer 22

Starch is glucose - it is needed for respiration.

Question 23

Where is protease made?

Answer 23

The stomach, pancreas, small intestine

Question 24

What does protease catalyse?

Answer 24

Digestion of proteins into amino acids

Question 25

Where does protease work?

Answer 25

Stomach and small intestine

Question 26

Where is lipase made?

Answer 26

The pancreas and small intestine

Question 27

What does lipase catalyse?

Answer 27

Digestion of lipids into fatty acids and glycerol

Question 28

Where does lipase work?

Answer 28

The small intestine

Question 29

What are lipids?

Answer 29

Lipids are fats and oils.

Question 30

What conditions do protease enzymes work best in? How is this maintained?

Answer 30

They work best in acidic conditions - glands in stomach will produce hydrochloric acid to create these conditions.

Question 31

What conditions do amylase and lipase work best in?

Answer 31

They prefer alkaline conditions.

Question 32

Where is bile stored and produced?

Answer 32

Bile is produced in the liver and is stored in the gall bladder.

Question 33

Describe bile’s role in the small intestine.

Answer 33

The hydrochloric acid from the stomach is too acidic for the enzymes in the small intestine to work properly. The alkaline bile is squirted into the small intestine to neutralise the stomach acid and make the conditions slightly alkaline.

Question 34

Describe bile’s role in digestion.

Answer 34

Bile emulsifies fats - it breaks them down into tiny droplets which increases the surface area for lipase enzymes to work on - making digestion faster.

Question 35

What do microorganisms produce for us that are helpful?

Answer 35

Some microorganisms produce enzymes that can pass out of their cells and these have many uses in industry.

Question 36

What do biological detergents contain?

Answer 36

They contain proteases and lipases as they can break down plant and animal matter and remove stains.

Question 37

What temperatures do biological detergents work best in?

Answer 37

They are more effective when working at lower temperatures (30 degrees) than other types of detergents.

Question 38

What enzymes are used in baby food?

Answer 38

Proteases in the food help the baby to digest the food as they are “pre-digested”.

Question 39

What do carbohydrases do to syrup?

Answer 39

They convert starch syrup into sugar syrup.

Question 40

What does isomerase do?

Answer 40

It turns glucose syrup into fructose syrup.

Fructose is sweeter and can be used in less quantities in slimming foods.

Question 41

Why are enzymes used in industry?

Answer 41

Enzymes can bring about reactions at normal temperatures that would otherwise demand expensive, energy demanding equipment to produce high temperatures and pressures.

Question 42

What are the advantages of using enzymes in industry?

Answer 42

Enzymes in biological washing powders are good at removing stains in clothes, such as blood, grass, and gravy.

Biological washing powders can be used at lower temperatures - saves energy and costs

Costs of equipment and energy usually required are reduced

Some enzymes in medicine can control, cure, or diagnose diseases.

Enzymes are specific - they only catalyse the reaction you want them to.

They work for a long time and can continually be used.

They are biodegradable.

Question 43

What are the disadvantages of using enzymes in industry?

Answer 43

They are expensive to produce.

Contamination may affect the enzymes.

Enzymes denature at the slightest change in pH or temperature - their conditions need to be tightly controlled.

Some may develop allergies to the powders in biological washing powders.

They may enter the waterways by the sewage system.