5 Answers
- Individuals homozygous for Cd grnes were crossed with wild type(++). The F1 hybrid thus prodused was test crossed to produced progeny in the following ratio ++900
Cd880
+d115
+C105 wht is dstn btw C&d
- What is the role or pith?
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- 3rd ionisation potential of Mg is greater than 3rd I.P. of Al. it's wrong why?
- what is triploblastic character?
- Is there any easy way to prepare for organic chemistry
- what book should b referred to score good marks in bio
- what is all india rank for 470 marks in neet
- hi can anyone guide me for medical, i mean for all medical exams and how to prepare, how many people give the test, how many selections for general, which books to use and all
- why our veins looks like blue or green colour?
Practice Mock Test
neet
The biuret test (Piotrowski's test) is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms violet-colored coordination complexes in an alkaline solution.[1] Several variants on the test have been developed, such as the BCA test and the Modified Lowry test.[2] The biuret reaction can be used to assess the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide. The intensity of the color, and hence the absorption at 540 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law. Despite its name, the reagent does not in fact contain biuret ((H2N-CO-)2NH). The test is named so because it also gives a positive reaction to the peptide-like bonds in the biuret molecule The Biuret reagent is made of sodium hydroxide (NaOH) and hydrated copper(II) sulfate, together with potassium sodium tartrate,[5] the latter of which is added to chelate and thus stabilize the cupric ions. The reaction of the cupric ions with the nitrogen atoms involved in peptide bonds leads to the displacement of the peptide hydrogen atoms under the alkaline conditions. A tri- or tetra-dentate chelation with the peptide nitrogen produces the characteristic color. This is found with dipeptides (Datta,S.P., Leberman,R., and Rabin,B.R., Trans.Farad.Soc. (1959), 55, 2141). The reagent is commonly used in the biuret protein assay, a colorimetric test used to determine protein concentration by UV/VIS spectroscopy at wavelength 550 nm.