AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA REPLICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
One difference between DNA and RNA is that ____
A
Only RNA has the base Uracil
B
only RNA contains the base Thymine
C
only RNA contains the base Cytosine
D
only RNA contained the base Guanine
Explanation: 

Detailed explanation-1: -There are two differences that distinguish DNA from RNA: (a) RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom), and (b) RNA has the nucleobase uracil while DNA contains thymine.

Detailed explanation-2: -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-3: -RNA contains uracil, while DNA contains thymine. Explanation: RNA is different than DNA in that it 1) is single stranded (DNA is double stranded), 2) contains uracil (DNA contains thymine instead), and 3) contains a ribose sugar (DNA contains a deoxyribose sugar).

Detailed explanation-4: -Uracil is one of these bases. However, since mRNA is relatively short-lived and any potential faults don’t result in any lasting damage, RNA employs uracil because the instability doesn’t matter as much for RNA. Thymine is also quickly oxidized. The thymine in the nucleus is shielded from oxygen.

Detailed explanation-5: -DNA and RNA base pairing is slightly different since DNA uses the bases adenine, thymine, cytosine, and guanine; RNA uses adenine, uracil, cytosine, and guanine. Uracil differs from thymine in that it lacks a methyl group on its ring.

There is 1 question to complete.