Exp. 2 - Protein Denaturation

Question 1

It is the modification in
conformation of protein accompanied by
disruption and possible destruction of secondary,
tertiary, and quaternary structure of protein.

Answer 1

Protein Denaturation

Question 2

What is the frequent consequence of protein denaturation?

Answer 2

Loss of solubility in water

Question 3

This occurs when denatured protein precipitates out

Answer 3

Coagulation

Question 4

Protein solution needed to observe the effect of denaturing reagents

Answer 4

Egg Albumin Solution

Question 5

Physical agent used to in denaturing proteins (used in the experiment)

Answer 5

Heat

Question 6

What are the 3 steps in testing the effect of heat on the egg albumin?

Answer 6

1. Add 1.0 ml of egg albumin sample in a test tube.
2. Heat in boiling water for 5 minutes.
3. Compare the results with the standard.

Question 7

How many mL of albumin sample is needed to test the effect of heat?

Answer 7

1 mL

Question 8

How many minutes should you boil the water to test the effect of heat?

Answer 8

5 minutes

Question 9

What are the 2 types of alcohol used to test the effect of alcohol on albumin?

Answer 9

95% and 70% ethanol

Question 10

EFFECT OF ALCOHOL: How many mL of sample solution and reagent per sample are used in the experiment?

Answer 10

2.0 mL of albumin solution (sample)
5 mL of alcohol reagent per sample

Question 11

What is the strong acid used in the experiment? (w/ mL)

Answer 11

1 mL of conc. HNO3 (nitric acid)

Question 12

TRUE/FALSE: The strong base used in the experiment is 1.5 mL of 30% sodium hydroxide

Answer 12

FALSE; 1mL of 50% NaOH

Question 13

TRUE/FALSE: (EFFECT OF STRONG ACID & BASE)

After adding the following reagents (50% NaOH and conc. HNO3) per albumin solution, you should shake the test tubes vigorously

Answer 13

FALSE; You should MIX THOROUGHLY, not shake

Question 14

What are the reagents used in testing the effect of heavy metals?

Answer 14

1 mL of 1% AgNO3 (Silver Nitrate)
1 mL of 1% CuSO4 (Copper Sulfate)

Question 15

EFFECT OF HEAVY METALS:

What should you do after shaking the 3 test tubes?

Answer 15

Note the color of the precipitates formed and set aside for 5 minutes

Question 16

TRUE/FALSE (EFFECT OF HEAVY METALS):

After setting the test tubes aside for 5 minutes, decant the supernatant liquid and test the solubility of a small portion of the precipitate in 5 mL H2O

Answer 16

TRUE

Question 17

What are the 2 alkaloidal reagents used in the experiment?

Answer 17

1 mL of 1% picric acid solution
1 mL of 1% tannic acid solution

Question 18

EFFECT OF ALKALOIDAL REAGENTS:

Should you shake the test tubes gently or vigorously?

Answer 18

GENTLY (!)

Question 19

Chemical formula of picric acid

Answer 19

C6H3N3O7

Question 20

Chemical formula of tannic acid

Answer 20

C76H52O46

Question 21

What are the 5 denaturing agents that will be used in the experiment?

Answer 21

1. Heat
2. Alcohol
   - 95% and 70% ethanol
3. Strong Mineral Acids (Acid & Base)
   - 50% NaOH & conc. HNO3
4. Heavy Metals
   - 1% AgNO3 & 1% CuSO4
5. Alkaloidal reagents
   - 1% picric acid solution & 1% tannic acid solution