Protein Precipitation and Salting Effects

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What are the complex acids known as, due to their original use?

Alkaloidal reagents (correct)
Protein reagents
Biological reagents
Tungestic reagents

What is the primary purpose of using complex acids in deproteinization of biological fluids?

To quantitatively determine proteins in serum
To precipitate proteins from biological fluids (correct)
To denature proteins using strong mineral acid
To analyze proteins in urine

What is the significance of adding precipitating agents drop-wise to protein solutions?

To increase the concentration of the protein solution
To speed up the precipitation reaction
To ensure complete precipitation of proteins
To prevent excess reagents from re-dissolving the formed precipitate (correct)

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

The protein molecules exist as anions in alkaline medium (B) Signup and view all the answers

What is the ideal condition for the precipitation reaction of protein solutions with salts of heavy metals?

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

What happens to albumins when they are fully saturated with (NH4)2SO4?

They are completely precipitated (D) Signup and view all the answers

What is the principle behind the precipitation of proteins by conc. HNO3?

The addition of strong mineral acid leads to protein denaturation (B) Signup and view all the answers

Why is excess NaOH used before adding copper sulfate in the Biuret's test after ammonium sulfate treatment?

To decrease the amount of ammonia liberated (A) Signup and view all the answers

What is the result of boiling the upper part of the solution after adding saturated (NH4)2SO4 solution to the egg white solution?

A coagulum indicates the presence of globulin (B) Signup and view all the answers

What is the nature of proteins in terms of their behavior in different mediums?

They are amphoteric in nature (B) Signup and view all the answers

What is the principle behind the precipitation of proteins by alkaloidal reagents?

Proteins react with the acid to form an insoluble salt (B) Signup and view all the answers

What is the purpose of testing for completion of precipitation of proteins after salt treatment and filtration?

To check if all proteins have been precipitated (A) Signup and view all the answers

What is the principle behind the salting out effect?

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

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

ammonium sulfate (D) Signup and view all the answers

Which of the following proteins is not readily precipitated by saturation with ammonium sulfate?

peptone (C) 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 (B) Signup and view all the answers

What is the difference between the half saturation test and the full saturation test?

amount of salt added (A) Signup and view all the answers

What is a limitation of the salting out effect?

it is not specific to proteins (A) Signup and view all the answers

What happens to proteins containing aromatic amino acids when heated with conc. HNO3?

They form a yellow color due to nitration of the benzene ring (C) Signup and view all the answers

What is the purpose of adding acid to the egg white solution in the protein detection test?

To precipitate the protein out of solution (D) Signup and view all the answers

What is the definition of denaturation of proteins?

The modification of protein structure that alters its physical and biological properties (A) Signup and view all the answers

What is the purpose of adding strong alkali to the protein solution in the Xanthoproteic Test?

To intensify the yellow color to orange (C) Signup and view all the answers

What is the significance of the isoelectric point of the protein in heat coagulation?

It is the point where the protein is electroneutral (B) Signup and view all the answers

What is the second step involved in heat coagulation of proteins?

Flocculation of the denatured protein (A) Signup and view all the answers