EXPT 4 - Precipitation, Denaturation, and Coagulation of Proteins

Question 1

is the unfolding of the complex secondary, tertiary, and quaternary structure of proteins.

Answer 1

Denaturation

Question 2

unfolded molecule will return to its native form when conditions become favorable in a process called

Answer 2

renaturation, refolding, or annealing

Question 3

TRUE OR FALSE

Denaturation is a reversible process.

Answer 3

TRUE

Question 4

renders the protein insoluble at isoelectric point, causing it to precipitate

Answer 4

Flocculation

Question 5

is the simple clumping together of dispersed chains of denatured protein

Answer 5

Flocculation

Question 6

when heated further, the clumped chains become matter together in a mass which is insoluble

Answer 6

Coagulation

Question 7

Give at least three denaturing agents of proteins.

Answer 7

-Sodium Dodecyl Sulfate (SDS)/Soaps or Detergents
-Guanidium hydrochloride (Urea)
-B-mercaptoethanol
-Heavy Metal Ions
-Alcohols
-Acids or Bases
-Alkaloidal reagents

Question 8

disrupts hydrophobic interactions, if charged, it can disrupt electrostatic interactions; disrupts disulfide bridges

Answer 8

B-mercaptoethanol (HS-CH2-CH2-OH)

Question 9

combines with positively
charged proteins and disrupts electrostatic interactions

Answer 9

Alkaloidal reagents

Question 10

split salt linkages by ionizing the carboxylic group, and alcohol denatures the protein by disrupting the hydrogen bonds.

Answer 10

strong acids

Question 11

process of leather production by coating animal skins with tannic acid

Answer 11

tanning

Question 12

are used as antiseptic and germicides by precipitating bacterial proteins.

Answer 12

Metallic salts

Question 13

The use of silver nitrate for _____________ of wounds and ulcers depends upon its property of precipitating tissue proteins.

Answer 13

cauterization

Question 14

Which has greater germicidal effect, pure alcohol (95%) or 70% alcohol?

Answer 14

70% alcohol has a greater germicidal effect. When allowed to stand in alcohol, proteins undergo irreversible change and is coagulated. This is taken advantage of in fixing of tissues for histological examination.

Question 15

antidotes used in metallic poisoning which form insoluble precipitate that can be removed subsequently by means of a stomach tube

Answer 15

egg white and milk

Question 16

A decrease in the quantity of proteins in the blood.

Answer 16

Hypoproteinemia

Question 17

Hypoproteinemia is caused by the following except;
a) excessive loss of serum proteins as with chronic renal disease
b) inadequate protein intake as with starvation or malnutrition
c) impaired protein production
d) all of the above

Answer 17

d) all of the above

Question 18

The presence of protein in the urine.

Answer 18

Proteinuria

Question 19

The presence of protein in the urine (proteinuria) may indicate the presence of damage to the ____________.

Answer 19

kidneys

Question 20

The presence of serum albumin, serum globulin or other serum proteins in the urine. This may be associated with kidney or heart disease, and may occur after strenuous exercise or after a long period of standing.

Answer 20

Albuminuria

Question 21

or breaking down of starch into simple sugars

Answer 21

hydrolysis