25 Questions
Which type of acid is trichloroacetic acid (TCA)?
Organic acid
What is an example of a mineral acid?
Conc.HNO3
Which type of acid can be denoted by the chemical formula H2SO4?
Mineral acid
In the context of the text, which of the following is most likely to react with metals to produce salts and hydrogen gas?
Mineral acid
Which type of acid is commonly used in chemistry experiments as a powerful oxidizing agent?
Conc.HNO3
What is the basis of the principle of protein precipitation using (NH4)2SO4?
Competition for H2O molecules with protein molecules
What is the effect of half-saturation with (NH4)2SO4 on serum globulin?
Precipitation of serum globulin
What is the role of (NH4)2SO4 in protein precipitation?
To neutralize the charge on protein molecules
What is the purpose of using (NH4)2SO4 in protein purification?
To induce dehydration and precipitation of proteins
What happens to protein molecules when they are subjected to (NH4)2SO4?
They are dehydrated and precipitated out
What are nucleoproteins composed of?
Protein part and nucleic acid part
What is the classification of nucleoproteins based on?
Types of nucleic acids they contain
What is the full form of DNP?
Deoxyribonucleoproteins
What is the chemical composition of DNA?
H3PO4 + deoxyribose + purine
What is the term for nucleoproteins that contain RNA?
RNP
What is a practical application of pI?
To isolate a certain protein by precipitation
What is a result of using pI in a biological extract?
A certain protein is isolated
What is the purpose of using pI in a biological extract?
To isolate a certain protein
What is the process by which a certain protein is isolated using pI?
Precipitation
What is the outcome of using pI with a biological extract?
A protein is isolated by precipitation
What is the product of the reaction between Na2S and Na plumbite (Pb(ONa)2)?
PbS
What is the purpose of color reactions in clinical biochemistry?
To identify and quantify proteins and amino acids in biological media
What is the reactant that forms a violet-red complex with Na2S?
Nitroprusside
What is the name of the reaction that produces a black precipitate of PbS?
Fohl’s Rxn
Which of the following tests is not a color reaction?
Fohl’s Rxn
Study Notes
Fohl's Reaction and Nitroprusside Reaction
- Fohl's reaction involves the reaction of Na2S with Na plumbite (Pb(ONa)2) to form a black precipitate of PbS.
- This reaction is used to detect sulphur-containing compounds like cysteine, cysteine, and methionine.
Nitroprusside Reaction
- Nitroprusside reaction involves the reaction of Na2S with Na nitroprusside to form a violet-red complex that fades over time.
- This reaction is used to detect sulphur-containing compounds like cysteine, cysteine, and methionine.
Color Reactions in Clinical Biochemistry
- Color reactions are used in clinical biochemistry to identify proteins and amino acids in biological media.
- Mineral acids like conc. HNO3 and organic acids like trichloroacetic acid (TCA) are used to detect proteins and amino acids.
Precipitation of Proteins
- Precipitation of proteins is based on the principle of neutralizing the charge on protein molecules using (NH4)2SO4.
- This induces dehydration of protein molecules, leading to precipitation (salting out).
- Half saturation with (NH4)2SO4 causes precipitation of serum globulin.
Nucleoproteins
- Nucleoproteins are composed of protein and nucleic acid parts (DNA and RNA).
- Nucleoproteins are classified into Ribonucleoproteins (RNP) and Deoxyribonucleoproteins (DNP).
- DNA is composed of DNA, H3PO4, deoxyribose, and purine, bound to a protein.
Isolation of Proteins
- The isoelectric point (pI) of a protein allows for its isolation by precipitation from biological extracts.
This quiz covers color reactions in clinical biochemistry including Fohl’s Reaction and Nitroprusside Reaction for identifying proteins and amino acids in biological media. Practical applications of these reactions are discussed.
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