EXAM 2 TRUE OR FALSE

Question 1

All polypeptide chains are proteins.

Answer 1

false

Question 2

Proteins are made of polypeptide chains.

Answer 2

true

Question 3

Sodium dodecyl sulfate (SDS) denatures proteins.

Answer 3

true

Question 4

Ion exchange chromatography allows the separation of proteins/polypeptides on the basis of charges.

Answer 4

false must be net charge.

Question 5

In Affinsen’s experiment, a denatured ribonuclease was renatured by slowly removing β-mercaptoethanol and urea.

Answer 5

true

Question 6

Proteins are classified according to their shape and solubility. Membrane proteins are proteins that bind to cell membranes. Membrane proteins are therefore soluble in
lipids.

Answer 6

false They are not soluble either in lipid nor in water solution. This is because of the presence of hydrophobic part in the structure of the molecule.

Question 7

The protein ovalbumin (egg white) is denatured by heat.

Answer 7

true

Question 8

A denatured protein has a different primary structure than a non-denatured protein.

Answer 8

true

Question 9

Denaturation of an enzyme will cause a loss of its catalytic activity.

Answer 9

true

Question 10

The number of amino acids commonly found in proteins is 22

Answer 10

false 20

Question 11

In the following polypeptide chain, Arg-Lys-Met-Cys-His-Trp-Val-Gly, the N-Terminal is Glycine and the C-Terminal is Arginine.

Answer 11

false n terminal is arginine c terminal is glycine

Question 12

Proteins absorb UV light at 280 nm. True/False

Answer 12

true

Question 13

Proteins are classified according to their shape and solubility. Membrane proteins are
proteins that bind to cell membranes. Membrane proteins are therefore soluble in
lipids

Answer 13

false

Question 14

Right-handed alpha-helix is most common in proteins than left-handed alpha-helix.

Answer 14

true