Enzymes

Question 1

Enzymes

Answer 1

They are proteins that speed up chemical reactions. Without enzymes, reactions can still occur but they would be too slow to support life. It is a catalyst.

Question 2

Globular Proteins

Answer 2

They form amino acids that have metabolic functions. They form enzymes.
They can help with: 
- Cell movement
- Transport
- Storage

Question 3

Catalyst

Answer 3

• They increase the rate of the reactions in the body.

- Without enzymes, metabolism would be too slow to sustain life.

Question 4

Substrate

Answer 4

A substance is acted upon by an enzyme. It is what binds to an enzyme which gives out a product.

Question 5

Active site

Answer 5

only specific molecules can fit into it, so enzymes are highly specific in their action.

Question 6

Lock and Key

Answer 6

the action of the enzyme and the substrate can be likened to a lock and key.

Question 7

Induced-fit

Answer 7

the substrates change the shape of the enzyme – they make the enzyme fit the substrates.

Question 8

Denaturing

Answer 8

• This means some of the bonds within it are destroyed and the whole enzyme molecule changes shape, as a result the active site will also change shape. So the enzyme is less effective, possibly even useless.

Question 9

Optimum temperature

Answer 9

• Enzymes are highly sensitive to temperature and pH levels (acidity or alkalinity).
• This means they can only act within a certain range of pH and temperature values.
• For example, in human cells enzymes work best between 35°C and 40°C.

Question 10

Metabolic poisons

Answer 10

• The reason is that such substances may block entry to or occupy active sites temporarily if they have the right shape

Question 11

Optimum concentration

Answer 11

• When all enzymes have a substrate molecule to work on or when all substrates have an enzyme to bind to, we call that the point of OPTIMUM CONCENTRATION.

Question 12

Activation energy

Answer 12

• Like all catalysts, enzymes work by lowering the ACTIVATION ENERGY for a reaction, thus dramatically increasing the rate of the reaction.

Question 13

Intracellular

Answer 13

(inside the cell) enzymes – where they speed up and control metabolic reactions

Question 14

Extracelluar

Answer 14

produced and secreted by the cells and act outside the cell. They include digestive enzymes, which breakdown food in the gut.

Question 15

Coenzymes

Answer 15

• are small organic molecules that TRANSPORT chemical groups from one enzyme to another.
• Some of these chemicals such as riboflavin, thiamine and folic acid are VITAMINS

Question 16

Product

Answer 16

A product is something “manufactured” by an enzyme from its substrate.

Question 17

Enzyme characteristics

Answer 17

1. All enzymes have an active site
2. They are very specific
3. They are recycled

Question 18

Enzyme action

Answer 18

1. The enzyme binds to the substrate
2. The enzyme catalyzes the substrate into a product
3. The enzyme releases the product

Question 19

What happens after the enzyme has completed the reaction?

Answer 19

It goes back to normal and produces more products

Question 20

Has the enzyme chemically changed after a reaction?

Answer 20

No

Question 21

How does an enzyme work?

Answer 21

It lowers the activation energy for a reaction. Therefore, the rate of the reaction is faster

Question 22

What are the two main factors that influence an enzymes effectiveness?

Answer 22

• Temperature

- pH

Question 23

What is the optimum environment for most enzymes?

Answer 23

Temperature: 37 degrees
pH: 7 (neutral)

Question 24

What happens to an enzyme outside its optimum environment?

Answer 24

It will denature.

Question 25

Reaction formula

Answer 25

Substrate –> product

Question 26

What is the rate of a chemical reaction?

Answer 26

1000 times a second

Question 27

Naming Enzymes

Answer 27

Most enzymes end in ‘ase” however pepsin, trypsin, rennin and ptyalin do not

Question 28

Where are enzymes made?

Answer 28

• They are made in the cytoplasm