A2- Proteins and Enzymes

Question 1

What region of amino acids are basic?

Answer 1

NH2

Question 2

What region of amino acids is acidic?

Answer 2

COOH

Question 3

What is a zwitterion?

Answer 3

a ion with separate positively and negatively charged groups (overall neutral charge)

Question 4

When do amino acids form zwitterions?

Answer 4

isoelectric point (usually around pH 6)

Question 5

What happens when amino acids are in alkaline conditions?

Answer 5

COOH dissociates, forming COO-

Question 6

What happens when amino acids are in acidic conditions?

Answer 6

NH2 gains H+, forming NH3+

Question 7

What is the primary structure of a protein?

Answer 7

sequence of amino acids

Question 8

What is the secondary structure of a protein?

Answer 8

Hydrogen bonds cause B-pleated sheets or a-helix to form

Question 9

When does a-helix form?

Answer 9

when NH2 groups are on the same side

Question 10

What is the tertiary structure of a protein?

Answer 10

hydrogen, ionic and disulfide bonds make 3D shape

Question 11

What is an enzyme?

Answer 11

protein-based biological catalyst, that speeds up rate of reaction by lowering Ea

Question 12

Why are enzymes specific?

Answer 12

• a specific active site that must fit and have intermolecular forces with a specific substrate.
• This promotes the movement of electrons which lowers Ea

Question 13

What is meant by the term ‘stereospecific’?

Answer 13

so specific that only one out of a pair of enantiomers will bind to the enzymes active site

Question 14

How can enzymes be denatured?

Answer 14

changing temp and pH