Unit 1 (KA4) Proteins

Question 1

What does the sequence of amino acids determine?

Answer 1

A protein’s shape and therefore it’s function.

Question 2

Name 5 functions of proteins in the body.

Answer 2

(S) - Structural
(H) - Hormones
(A) - Antibodies
(R) - Receptors
(E) - Enzymes

Question 3

State the function of an enzyme.

Answer 3

Enzymes are biological catalysts. They help to speed up chemical reactions in cells, without being changed themselves.

Question 4

Describe enzyme action using keywords.

Answer 4

Enzymes bind with their substrates at their active site. The active site has a complementary shape (is specific) to the substrate. This allows them to fit together. An enzyme-substrate complex forms and the reaction takes place. Products are formed and released by the enzyme. The enzyme can now be used again.

Question 5

What is a degradation reaction?

Answer 5

A degradation reaction is a breakdown reaction. The substrate is one large molecule and the product is two or more smaller molecules.

Question 6

What is a synthesis reaction?

Answer 6

A synthesis reaction is a build up reaction. The substrate is two or more smaller molecules and the product is one large molecule.

Question 7

How does pH and temperature affect enzymes and the rate of reaction?

Answer 7

Enzymes are most active at their optimum conditions. An increase in temperature, or a high or low pH causes proteins to lose their shape. The protein is said to be denatured. This lowers the rate of reaction because the active site will no longer fit the substrate.