Protein Precipitation: Salting Out and Salting In Effects

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What is the effect of full saturation with (NH4)2SO4 on albumins?

They are dissolved
They are not precipitated
They are completely precipitated (correct)
They are partially precipitated

Why is excess NaOH required before adding copper sulfate in Biuret's test?

To remove excess ammonium sulfate
To consume most of the alkali added (correct)
To increase the pH of the solution
To reduce the amount of copper sulfate

What is the result of adding an equal volume of saturated (NH4)2SO4 solution to 10 ml of egg white solution?

A white precipitate of globulin is obtained (correct)
The solution becomes acidic
A white precipitate of albumin is obtained
No precipitate is formed

What is the purpose of boiling the upper part of the solution in the separation of globulin and albumin?

To coagulate globulin (D) Signup and view all the answers

What is the nature of proteins, according to the principle of precipitation by alkaloidal reagents?

Amphoteric (C) Signup and view all the answers

What is the result of the reaction between proteins and alkaloid reagents?

Formation of an insoluble salt (A) Signup and view all the answers

What is the effect of adding a high concentration of neutral salts to a protein solution?

Precipitation of proteins (B) Signup and view all the answers

What is the primary purpose of using alkaloidal reagents in biological fluids?

To precipitate proteins (A) Signup and view all the answers

What is the principle behind the salting out effect?

Dehydration of protein particles and neutralization of protein electrical charges (D) Signup and view all the answers

What is the consequence of adding excess precipitating agents to protein?

Re-dissolution of the formed precipitate (B) Signup and view all the answers

What is the most commonly used salt in the salting out effect?

Ammonium sulfate (B) Signup and view all the answers

What is the principle behind the precipitation of proteins by salts of heavy metals?

Neutralization of protein particles (B) Signup and view all the answers

What is the ideal condition for the precipitation of proteins by salts of heavy metals?

Slightly alkaline medium (A) Signup and view all the answers

What is the purpose of the salting out effect in protein separation?

To separate individual proteins from a mixture (C) Signup and view all the answers

What type of proteins are not readily precipitated by saturation with ammonium sulfate?

Peptone (B) Signup and view all the answers

What is the result of adding conc. HNO3 to protein?

Denaturation of proteins (D) Signup and view all the answers

What is the name of the test where a certain volume of saturated salt solution is added to the same volume of protein solution?

Half Saturation Test (D) Signup and view all the answers

What is the term used to describe the complex acids used in the precipitation of alkaloids?

Alkaloidal reagents (A) Signup and view all the answers

What happens to the protein when heat is applied?

It undergoes denaturation (C) Signup and view all the answers

What is the purpose of adding acid to the solution in the precipitation test?

To neutralize the negative charge of the protein (D) Signup and view all the answers

What is the result of heating proteins containing aromatic amino acids with conc.HNO3?

A yellow color is formed (B) Signup and view all the answers

What is the definition of denaturation of proteins?

A non-hydrolytic modification of the structure of the protein (C) Signup and view all the answers

What is the purpose of the test where a white ring of protein precipitate is formed?

To detect the presence of albumin in urine (D) Signup and view all the answers

What happens to the nitro compound formed in the Xanthoproteic Test when strong alkali is added?

It intensifies the color to orange (D) Signup and view all the answers