EVERYDAY SCIENCE

SCIENCE

CELL BIOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following is not a constituent of DNA molecule?
A
Adenine
B
Cytosine
C
Thymine
D
Uracil
Explanation: 

Detailed explanation-1: -Nucleotides that make the DNA strands contain deoxyribose sugar, phospate molecule and one nitrogenous base out of adenine, guanine, thymine and cytosine. Uracil is never a part of nucleotide of DNA. It is present in RNA.

Detailed explanation-2: -Hence, the correct option is (B) Guanidine.

Detailed explanation-3: -Uracil (U) is one of the four nucleotide bases in RNA, with the other three being adenine (A), cytosine (C) and guanine (G). In RNA, uracil pairs with adenine. In a DNA molecule, the nucleotide thymine (T) is used in place of uracil.

Detailed explanation-4: -Explanation of correct option: The uracil is a nitrogen base of pyrimidine. The uracil present in RNA(ribonucleic acid) bonds with a double hydrogen bond with Adenine while absent in DNA(Deoxyribonucleic acid).

Detailed explanation-5: -DNA is made of two linked strands that wind around each other to resemble a twisted ladder-a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases: adenine (A), cytosine (C), guanine (G) or thymine (T).

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