B4 Enzymes

Question 1

What is a catalyst?

Answer 1

A substance that changes the speed of the reaction, often making it faster

Question 2

Enzymes are specific to what?

Answer 2

To one substance or a group of similar-shaped substrates

Question 3

An active site is a sequence of…?

Answer 3

Amino acids with a specific shape

Question 4

Protease breaks down…?

Answer 4

Proteins into amino acids

Question 5

List the factors affecting enzyme action

Answer 5

• pH

- Temperature

Question 6

Define enzyme

Answer 6

Proteins that function as biological catalysts

Question 7

Define enzyme

Answer 7

Proteins that function as biological catalysts

Question 8

The active site and substrate are ______.

Answer 8

complementary

Question 9

Substrate fits tightly into the active site, forming an _______.

Answer 9

Enzyme-substrate complex

Question 10

Once products are formed, they no longer fit into the _____.

Answer 10

active site

Question 11

Amylase breaks down…?

Answer 11

Starch into simple sugars

Question 12

Lipase breaks down…?

Answer 12

Lipids into fatty acids and glycerol

Question 13

Enzymes work best at what temperature?

Answer 13

Optimum

Question 14

Why won’t enzymes work at higher temperatures?

Answer 14

Since the structure of the enzyme has permanently changed. The enzyme has denatured.

Question 15

Why do enzymes work best at their optimum temperature?

Answer 15

The molecules have the perfect amount of kinetic energy at this temperature

Question 16

Why do enzymes work more slowly at low temperatures?

Answer 16

This is because the enzyme and substrate molecules move slowly, so they may take a long time to bump into each other with enough force to join and start the reaction.

Question 17

Why are enzymes denatured past their optimum temperature?

Answer 17

This is because the molecules vibrate so much that they start to change the shape of the active site. This means that the substrate doesn’t fit as well, so the chance of an enzyme-substrate molecule forming decreases. The rate of reaction decreases.

Question 18

What is pepsin?

Answer 18

An enzyme released in the stomach(acidic).

Question 19

What is trypsin?

Answer 19

An enzyme released in the small intestine(alkaline).

Question 20

The shape of the enzyme depends on the ___.

Answer 20

Optimum pH

Question 21

A very high pH can ____ the enzyme

Answer 21

denature

Question 22

A very low pH can ____ the rate of action of the enzyme

Answer 22

Slows down

Question 23

Explain the investigation of pH on enzymes

Answer 23

1. Once tube for each pH
2. Add buffer solution
3. Add starch and amylase solution
4. Sample and test for starch with iodine solution
5. The sample that is the first to stop turning iodine solution blue-black comes from the tube where digestion of starch to glucose was fastest, and therefore from the tube kept at the optimum pH for that enzyme.