EMBRYOLOGY
CHROMOSOMES AND CELL DIVISIONS
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Guanine
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Thymine
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Cytosine
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Adenine
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Detailed explanation-1: -Adenine always pairs with thymine through two hydrogen bonds in DNA. Similarly, adenine pairs with uracil through two hydrogen bonds in RNA and guanine always pairs with cytosine through three hydrogen bonds in both the nucleic acids.
Detailed explanation-2: -Base pairing between adenine and thymine can be found in DNA only. There are two hydrogen bonds holding the two nitrogenous bases together. One of the hydrogen bonds is formed between one of the Hydrogen atoms of the amino group at C-6 of adenine and the Oxygen atom of the keto group at C-4 of thymine.
Detailed explanation-3: -The four bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). These bases form specific pairs (A with T, and G with C). Base pair may also refer to the actual number of base pairs, such as 8 base pairs, in a sequence of nucleotides.
Detailed explanation-4: -Guanine and thymine are similarly incompatible. A always pairs with T and G always pairs with C because these are the only combinations that allow for hydrogen bonding to occur, given the spatial constraints of the double helix, which requires there to be one purine and one pyrimidine in each base pair.