Week 3 (Amino Acids And basic Protein Structure)

Question 1

What kind of proteins/ protein apparatus can genes encode?

Answer 1

• enzymes
• structural proteins
• transport proteins
• rRNA
• tRNA
• snRNA

Question 2

Describe the 4 levels of protein structure

Answer 2

Primary structure: sequence of amino acids
Secondary structure: folding of the peptide chain into alpha helixes and beta pleated sheets
Tertiary structure: association of alpha helixes and beta pleated sheets with each other
Quaternary structure: association of separate folded polypeptides

Question 3

Explain the primary structure

Answer 3

• Linear polymer of amino acids

- Directly controlled by gene sequence, via the genetic code

Question 4

Explain the secondary structure

Answer 4

• Directly controlled by amino acid sequence
• structures are held together by hydrogen bonds between parts of different peptide bonds
• this promotes the formation of alpha helices, beta pleated sheets or sometimes random coils

Question 5

What is a zwitterion?

Answer 5

An ion or molecule with opposite charges

Question 6

What direction are all alpha helices?

Answer 6

Right hand

Question 7

Explain the tertiary structure

Answer 7

• controlled by amino acid side groups

- structures are held together by side groups protruding from the alpha helices and the beta pleated sheets

Question 8

explain the quaternary structure

Answer 8

Differently combined polypeptides (sub units) assembled ingka

Differently folded polypeptide (subunits) assembled

Question 9

What is special ablot proline?

Answer 9

It is an imino acid