Lecture 5 - Peptides and Peptide Bonds

Question 0

What transports amino acids to the ribosome?

Answer 0

tRNA molecules

Question 1

Post-translational modifications of amino acids in proteins

Answer 1

Proteome

Question 2

Why is the peptide bond (bond between the carboxyl group of one amino acid and the amine group of another amino acid) short?

Answer 2

Because the C-N bond has some double bond character (40%) due to resonance with the C=O group.

Question 3

Torsion angle between alpha C and N

Answer 3

Phi (φ)

Question 4

Torsion angle from C=O to alpha C

Answer 4

Psi (ψ)

Question 5

Torsion angle of the peptide bond

Answer 5

Omega (ω)

Question 6

Which amino acid is found in the cis configuration?

Answer 6

Proline, due to its cyclical structure

Question 7

How can you estimate the number of amino acid residues in a protein?

Answer 7

Dividing the molecular weight by 110

Question 8

The number of peptide sequences possible is given by what formula?

Answer 8

(Number of possible AA’s)^(peptide length)

Question 9

Which nonpolar, aliphatic R group amino acid occurs the most in proteins?

Answer 9

Leucine (9.1%?)

Question 10

Which aromatic R group amino acid occurs the least in proteins?

Answer 10

Tryptophan (1.4%)