Enzymes

Question 1

What are enzymes made from?

Answer 1

Protein

Question 2

What are enzymes?

Answer 2

Biological catalysts which speed up chemical reactions in cells without being used up

Question 3

What is an enzyme’s substrate?

Answer 3

The substrate is what the enzyme will break down

Question 4

Where on the enzyme does the substrate bind?

Answer 4

The active site

Question 5

Enzymes are specific. What does this mean?

Answer 5

Each enzyme catalyses a specific reaction. E.g. it breaks down a particular molecule. This is because the active site is a complementary shape to the substrate molecule.

Question 6

What do protease enzymes do?

Answer 6

Break down proteins into amino acids

Question 7

What do lipase enzymes do?

Answer 7

Break down fats into fatty acids and glycerol

Question 8

What do amylase enzymes do?

Answer 8

Break down starch into sugar

Question 9

What do carboydrase enzymes do?

Answer 9

Break down carbohydrates into sugars (amylase is an example of a carbohydrase enzyme)

Question 10

What does the lock and key model of enzyme action mean?

Answer 10

The shape of an enzymes active site is complementary to the shape of the substrate. The substrate fits into the active site like a key into a lock.

Question 11

What does it mean if an enzyme has become denatured?

Answer 11

The enzyme’s active site has changed shape. The enzyme no longer works.

Question 12

What happens to the rate of an enzyme controlled reaction if temperature increases?

Answer 12

at first, increasing the temperature will cause the rate to increase. At high temperatures the rate will decrease again.

Question 13

What is the optimum temperature of an enzyme?

Answer 13

The temperature where the rate of reaction is highest.

Question 14

Why does changing the temperature affect the rate of an enzyme controlled reaction?

Answer 14

Increasing temperature causes rates to increase because the substrate and enzymes have more energy so are more likely to collide. At high temperatures, the active site changes shape and the enzyme becomes denatured, meaning the rate decreases

Question 15

What happens to the rate of an enzyme controlled reaction if substrate concentration increases?

Answer 15

Increasing substrate concentrations causes rate of reaction to increase. At high concentrations, increasing substrate concentration has no effect on rate of reaction.

Question 16

Why does changing the substrate concentration affect the rate of an enzyme controlled reaction?

Answer 16

Increasing substrate concentrations means that there are more substrate particles, so they are more likely to collide with the active site of an enzyme. At high substrate concentrations, all the enzyme active sites are filled, so the rate does not increase any more.

Question 17

What happens to the rate of an enzyme controlled reaction if pH increases?

Answer 17

At low pH, rate of reaction is 0. As pH increases, rate of reaction increases to optimum pH and then decreases again to 0.

Question 18

What is the optimum pH of an enzyme?

Answer 18

The pH where the rate of an enzyme controlled reaction is highest.

Question 19

Why does changing pH affect the rate of enzyme controlled reactions?

Answer 19

At low or high pHs, the active site of the enzyme changes shape, causing it to denature and rate to be 0.

Question 20

What is the optimum temperature for enzymes in the human body?

Answer 20

37 degrees C

Question 21

What is the optimum pH for enzymes in the human body?

Answer 21

Depends on the enzyme. Enzymes in the stomach have a lower optimum pH (pH2) in order to work in the acidic environment. Other enzymes may have a higher optimum pH