Enzymes

Question 1

What is an enzyme?

Answer 1

Enzymes are Biological Catalysts. They increase the rate of Metabolic reactions.

Question 2

What is activation energy?

Answer 2

The energy required for a reaction to start

Question 3

What do enzymes do in reactions?

Answer 3

Enzymes lower the activation energy and therefore speed up a reaction

Question 4

Define active site?

Answer 4

Part of an enzyme molecule ibn which the substrate fits into during a biological reaction. It must have a complementary shape for it to work

Question 5

Define substrate?

Answer 5

In biochemistry, the substrate is a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate(s). In the case of a single substrate, the substrate bonds with the enzyme active site, and an enzyme-substrate complex is formed.

Question 6

Define products?

Answer 6

The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products.

Question 7

What are the two enzyme models?

Answer 7

The lock and key model

The induced-fit model

Question 8

What is the induced fit model?

Answer 8

The induced-fit model explains before the substrate binds to the enzyme the substance and active site are not precisely complementary in shape. As it binds the active site changes shape and moulds around the substrate.

Question 9

Which is more accurate the lock and key or induced fit model?

Answer 9

Induced fit model

Question 10

What is the lock and key model?

Answer 10

The lock and key model is the idea the active site and substrate directly fit into each other and each individual one will fit into the other so no other ones will be able to.

Question 11

What factors influence the rate of reaction and enzymes?

Answer 11

• pH
• Temperature
• Presence of inhibitors
• concentration

Question 12

What does denatured mean?

Answer 12

A permanent change to the shape of an enzyme or other protein that occurs as a result of breaking the bonds that maintain its tertiary structure.

Question 13

What causes enzymes to denature?

Answer 13

• The temperature being too high

- change in pH

Question 14

What is the optimum temperature?

Answer 14

The best temperature for the reaction to take place is the optimum temperature. The rate of reaction will be at its fastest here.

Question 15

What effects the pH of a substance?

Answer 15

The more hydrogen ion concentration in a substance the lower the pH will be. This is because there will be fewer acid ions. As pH falls one point eg from 7 to 6 the hydrogen ion concentration times by ten.

Question 16

What are enzyme inhibitors?

Answer 16

Inhibitors slow down the rate of enzyme-controlled reactions.

Question 17

What are the two types of inhibitors?

Answer 17

Competitive inhibitors and non competitive inhibitors.

Question 18

What are competitive inhibitors?

Answer 18

A competitive inhibitor blocks the active site which stops enzymes being able to join. When the concentration of enzymes is greater than inhibitors the inhibitor is removed. They are overcome when substrate is greater than inhibitor.

Question 19

What are non-competitive inhibitors?

Answer 19

Non-competitive inhibitors bind to the enzyme somewhere other than the active site. This causes the entire enzyme to change shape and disablers it permanently.

Question 20

Why are collisions significant?

Answer 20

Within reactions, enzymes and substrates must come together and they do that via collisions. More successful collisions in a given time period lead to a faster rate of reaction.

Question 21

What impacts collisions?

Answer 21

• The temperature will increase energy and speed and therefore collisions and successful collisions
• Concentration increases the chances of collisions.

Question 22

Keywords:

Answer 22

• Enzyme substrate complex
• Active site
• Inhibitors
• Substrate
• Concentration