[Unit 1.6] | Proteins

Question 1

Describe what atoms or functional groups make up an amino acid, and state their position relative to the central carbon.

Answer 1

• 1 H atom above the central carbon
• Variable R group below (changes for every type of amino acid)
• Amine/base group on the left (NH₂)
• Carboxyl/acidic group on the right (-COOH)

Question 2

What amino acid has the simplest R group, containing a single H atom?

Answer 2

Glycine

Question 3

When the OH of a carboxyl group aligns with the H of an amine group, what occurs during condensation?

Answer 3

The 3 atoms are removed to form water (H₂O) and a peptide (C-N) bond is created.

Question 4

Define the primary structure of a protein.

Answer 4

The number, type and sequence of amino acids.

Question 5

What is the secondary structure of a protein?

Answer 5

The folding and arrangement of atoms due to hydrogen bonding. It can form a beta pleated sheet or alpha helix coil.

Question 6

What is the tertiary structure of a protein?

Answer 6

The 3D folding due to ionic bonding, hydrogen bonding and disulphide bridging.

Question 7

What is the quaternary structure of a protein?

Answer 7

Involves 2 or more polypeptide chains and is often associated with non-protein groups.