This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
[{'content': 'Biuret test is used for detection of: \nSelect and explain. \nA. Protein, B. Cholesterol, C. Steroid, D. Sugar', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans: a (Protein) Ref: Vasudevan 4th ed/p.23, 24. 34.Biuret reaction:-* Cupric ions chelate with peptide bonds of proteins in alkaline medium to produce a pink or violet colour. This needs a minimum of two peptide bonds and so individual amino acids and dipeptides will not answer this test.* Biuret reagent - CuS04, sodium potassium tartarate and potassiumiodide in sodium hydroxide.* The intensity of colour is directly proportional to the peptide bonds and is estimated colourimetrically.Other tests:Fouchet'stest-Bile pigmentsHay's sulphur test- Bile saltsBenedict's test- Blood sugarRothera's test- Ketone bodiesReagentsEhrlich's aldehyde - Porphobilinogen and UrobilinogenFouchet's reagent - Bile pigmentBenedict's reagent - GlucoseSodium nitroprusside - Ketones", 'role': 'assistant'}]