Biology : PU-CET (U.G) 2016 Panjab University Entrance Exam With Answers

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16.

Which Of The Following Statement Is Incorrect About Histone Proteins ?

A: They Are Highly Basic Because They Contain Many Positively Charged Amino Acid Side Chains
B: They Are Extensively Modified After Their Translation
C: In Eombination With DNA, They Are Primary Constituents Of Chromatin
D: They Account For Approximately One-Fifth Of The Mass Of A Chromosome

The answer is: D

Explanation

The incorrect statement about histone proteins is D: They account for approximately one-fifth of the mass of a chromosome.

Histone proteins are highly basic because they contain many positively charged amino acid side chains, and they are extensively modified after their translation. They are in combination with DNA, primary constituents of chromatin, which is the material that makes up chromosomes. However, the amount of histone proteins in a chromosome is much higher than one-fifth of the chromosome's mass. In fact, histone proteins make up about half of the protein content of a chromosome and about one-third of its mass.