3.1 Proteins, Catalysts and Enzymes

Question 1

Different arrangements of amino acids make different proteins. Name 4 things proteins act as

Answer 1

• structural components of tissues
• hormones (such as insulin)
• antibodies that destroy pathogens
• catalysts in the form of enzymes

Question 2

What is a catalyst?

Answer 2

A chemical used to speed up the rate of a reaction without having an effect on the reactants and can be used over and over again

Question 3

What is an enzyme?

Answer 3

A biological enzyme that speeds up reactions in an organism

Question 4

What is the active site?

Answer 4

The part of an enzyme where other molecules fit in

Question 5

Why is the shape of the active site important?

Answer 5

Each enzyme has an active site specifically for one type of molecule. Of the enzyme gets denatured then the shape of the active site changes and it no longer works to catalyse reactions with those certain molecules

Question 6

What are protein molecules?

Answer 6

Small units of amino acids strung into long chains

Question 7

What are the molecules called that use enzymes to catalyse them?

Answer 7

Substrates

Question 8

What do enzymes do to substrates?

Answer 8

Either break them down or connect them together

Question 9

Name 3 things that enzymes can do.

Answer 9

• build large molecules from many smaller ones (eg build starch from glucose)
• change one molecule into another one (eg convert one type of sugar into another one)
• break down large molecules into smaller ones (eg all the digestive enzymes do this)

Question 10

Explain how enzymes work.

Answer 10

1. The substrate(s) enters the active site of the enzyme
2. They bind together
3. The reaction takes place rapidly
4. The products are released from the active site
5. The enzyme is ready to be used again