Enzymes

Question 1

Explain the action of enzymes in a reaction:

Answer 1

1. Lock-and-key mechanism
2. Substrate enters the enzyme’s active site
3. Products leave the enzyme
4. Enzyme remains intact

Question 2

Define catabolic reaction:

Answer 2

Molecules are broken down

Question 3

Define anabolic reaction

Answer 3

Molecules are combined

Question 4

Effect of temperature on enzymes

Answer 4

• at optimum temp (normally 40 degrees Celsius), enzymes will react fastest
• at temps too high, enzymes denature
• low temps will not kill enzymes, but as there isn’t enough energy to work efficiently, they will react extremely slowly

Question 5

Effect of pH on enzymes

Answer 5

• optimum pH differs for each enzyme

- when exposed to pH levels too far from an enzyme’s optimal pH, it will denature

Question 6

Reaction catalysed by amylase

Answer 6

Starch —> sugars

Question 7

Reaction catalysed by protease

Answer 7

Proteins —> peptides/amino acids

Question 8

Define lipase

Answer 8

Lipids —> fatty acids + glycerol

Question 9

Organs producing amylase

Answer 9

• salivary glands
• pancreas
• small intestine

Question 10

Organs producing protease

Answer 10

• stomach
• pancreas
• small intestine

Question 11

Organs producing lipase

Answer 11

• pancreas

- small intestine

Question 12

Define enzyme:

Answer 12

Proteins functioning as biological catalysts

Question 13

Define catalyst

Answer 13

• substance that speeds up reaction

- is not changed by the reaction

Question 14

Use of enzymes in seed germination

Answer 14

Seeds contain stored substances, such as starch, proteins, and fats. Enzymes break down these materials so that they can be used in growth, energy, and building cells.

In order for germination to occur, these conditions must be present:

• water: to activate the enzymes
• oxygen: to be used in respiration
• suitable (warm) temp.: so that enzymes can work faster

Question 15

Use of enzymes in biological washing powders

Answer 15

Enzymes beak down an insoluble stain on clothing into smaller soluble substances, which dissolve in the water.
E.g. If the shirt is stained by blood, protease in the powder will break down the insoluble proteins into peptides, to be washed away.

Question 16

Use of enzymes in baking

Answer 16

Both yeast and sugar are used. Yeast contains enzymes that ferment sugar through anaerobic respiration, producing carbon dioxide bubbles that cause dough to rise.

Question 17

Use of enzymes in brewing

Answer 17

Fermentation is involved to produce alcohols and carbon dioxide (to give wine/beer sparkle). The fermentation reactions are catalysed by enzymes produced by yeast.

Question 18

Role of enzymes in making juices

Answer 18

In fruits, a substance called pectin holds the cells together; this makes it hard to squeeze the juice out.
Pectinase helps break down pectin and makes the juice look clear instead of cloudy.

Question 19

Role of enzymes in making baby foods

Answer 19

Babies find it difficult to digest high-protein foods, so protease is used to break down the protein in the food to amino acids, which makes it easier for newborns to absorb and assimilate them.

Question 20

Role of enzymes in sugar production

Answer 20

Sugar is obtained from starch by using amylase to break down starch to maltose.
Fructose is a type of sugar most dieters prefer because it provides a sweet taste at a lower quantity than other sugars. It can be obtained from glucose using isomerase to catalyse the breakdown reaction.

Question 21

Describe the enzyme extraction process in a fermenter

Answer 21

1. Microorganism and feedstock are added. The liquid is maintained at 26 degrees with a pH of 5-6.
2. The microorganisms produce 2 types of enzymes, either extra-cellular or intra-cellular.
3. Extra-cellular enzymes are extracted from the feedstock through filtering
4. Intra-cellular enzymes are extracted by filtering the microorganisms, crushing them, washing them with water, then extracting them from the solution.

Question 22

Describe the steps of antibiotic production in a fermenter

Answer 22

1. The fermenter is filled with a sugar solution or corn liquor (which contains sugars and peptides)
2. Minerals are added, temp is adjusted to 26 Celsius, pH is adjusted to 5-6
3. The liquid is stirred and air is blown through it
4. Microorganism are added and allowed to grow for 1-2 days under sterile conditions
5. Antibiotics are secreted when nutrient supply decreases
6. The fluid containing antibiotics is filtered and the antibiotics are extracted

Question 23

Fermenter structural essentials

Answer 23

• water jacket: maintains constant temperature by convecting heat away
• paddles: to stir the mixture, stopping waste from building up and keeping the air evenly mixed
• nutrient medium: supplies microorganisms with fuel for respiration
• sterile air supply: supplies O2 (is not required in anaerobic fermentation processes)
• data logger: monitors temp/pH and keeps fermenter at optimal conditions

Question 24

What is penicillin?

Answer 24

An antibiotic produced by a fungus called penicillium