1.4 Proteins

Question 1

What does the sequence of amino acids control?

Answer 1

Controls the shape and function of proteins

Question 2

What are the 5 types of proteins?

Answer 2

Structural, hormones, antibodies, receptors, enzymes

Question 3

Describe the role of structural proteins

Answer 3

Hold tissues together e.g. collagen

Question 4

Define hormones

Answer 4

Chemical messengers which carry a message from a gland to a receptor via the blood

Question 5

What are antibodies?

Answer 5

Proteins, made by white blood cells, which destroy pathogens by binding to them

Question 6

Define receptors

Answer 6

Bind to a hormone and tell the target cell what to do.

Question 7

Define enzymes

Answer 7

Biological catalysts e.g. amylase and are made by all living cells

Question 8

Describe a biological catalyst

Answer 8

Speeds up chemical reactions in cells and remain unchanged in the process

Question 9

Define active site

Answer 9

Where the substrate fits into the enzyme and is a complementary shape to it

Question 10

Define substrate

Answer 10

The reactant(s) in a reaction, and is specific to an enzyme

Question 11

Define product

Answer 11

The molecule(s) made by an enzyme-controlled reaction

Question 12

Define optimum conditions

Answer 12

The temperature and pH which the enzymes are most active

Question 13

Define denatured

Answer 13

When the active site changes shape, the substrate no longer fits, and this affects the rate of the reaction

Question 14

An example of a degradation reaction is

Answer 14

Starch ——amylase—-→ maltose

Question 15

An example of a synthesis reaction is

Answer 15

G-1-P —–phosphorylase—–→ starch

Question 16

How does temperature affect enzymes’ rate of reaction?

Answer 16

A s temperature increases ,the rate of reaction increases until after the optimum is reached when rate of reaction rapidly decreases to zero

Question 17

Why do enzymes stop working past their optimum temperature?

Answer 17

Enzyme is denatured (substrate can no longer bind to active site)

Question 18

Why do enzymes not work well at lower temperatures?

Answer 18

There is not enough kinetic energy for the substrate to collide and bind to active site

Question 19

How does a change in pH affect enzyme structure?

Answer 19

pH change affects the bonds holding enzyme structure together, causing it to denature