Which amino acid is encoded by start codon (only one correct answer)

a) Methionine

b) Leucine

c) Isoleucine

d) Start codon doesn't encode any amino acids

Which amino acids would most likely reside in themembrane-anchoring domain of a membrane embedded protein?

a) Phenylalanine, valine, and aspartate

b) Lysine, arginine and histidine

c) Isoleucine, valine and phenylalanine

d) Leucine, threonine, and lysine

Given a mixture of GIVE (AMINO ACIDS, GLYCINE, ISOLEUCINE, VALINE, GLUTAMIC ACID,) and TAKE (ALSO AMINO ACIDS), and buffers at pH 2,7 and 10, which buffer would you use to achieve their electrophoretic separation. Explain the answer based upon the charges on the two molecules.

Type molecular weight Number in lysozyme

Alanine 89 12

Arginine 174 11

Asparagine 132 13

Aspartic acid 133 8

Cysteine 121 8

Glutamic acid 147 2

Glutamine 146 3

Glycine 75 12

Histidine 155 1

Isoleucine 131 6

Leucine 131 8

Lysine 146 6

Methionine 149 2

Phenylalanine 165 3

Proline 115 2

Serine 105 10

Threonine 119 7

Tryptophan 204 6

Tyrosine 181 3

Valine 117 6

1. The sequence of amino acids of the enzyme lysozyme is known. Below is a list of amino acids

and the number of each in the lysozyme molecule

Questions:

a. What is the average molecular weight of the 20 amino acids?

b. What is the molecular weight of lysozyme?

c. What is the average molecular weight of the amino acids in lysozome?

d. How many S-S bonds are possible in lysozyme?

(hint: look at the structures of each amino acid, and figure out which of these have sulphurs

that are FREE to form bonds).

e. Is the net charge on lysozyme positive or negative?