OBJECTIVE LIFE SCIENCE
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The amount of guanine plus cytosine in mammalian genomes varies from about 39 to 46%.
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DNA is always double stranded and RNA is always single stranded.
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DNA contains two grooves, a major groove and a minor groove.
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In DNA the number of adenine residues is identical to the number of thymine residues and the number of guanine residues is identical to the number of cytosine residues.
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DNA contains two strands that run in opposite directions.
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Detailed explanation-1: -Erwin chargaff gave then rule that demonstrate the nitrogenous component of the DNA double helix and such rule is called as chargaff’s rule. It states that the DNA of all the organism have equal number of purine and pyrimidine i.e., in 1 : 1 ratio.
Detailed explanation-2: -Chargaff’s rule states that the amount of adenine (A) is equal to that of thymine (T) and the amount of guanine is equal to that of cytosine (C) in an organism.
Detailed explanation-3: -Chargaff’s rules states that DNA from any cell of all organisms should have a 1:1 ratio of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.
Detailed explanation-4: -This sentence refers to the work of Erwin Chargaff, a biochemist at Columbia University. In the late 1940s, Chargaff analyzed the proportions of the four different types of base molecules in DNA, and found that DNA always contains equal amounts of guanine and cytosine, and equal amounts of adenine and thymine.
Detailed explanation-5: -Since the DNA strands are complementary, a rule called “Chargaff’s Rule” states the amount of adenine in the DNA of a living organism is equal to the amount of thymine in the DNA. It also states that the amount of cytosine in the DNA of a living being is equal to the amount of guanine in the DNA.