What is wrong with the following piece of mRNA? TACCAGGATCACTTTGCCA Multiple Choice It contains A. O It does not include an equal number of As and Ts. It does not include an equal number of Gs and Cs. It contains T and not U. What is wrong with the following piece of mRNA? TACCAGGATCACTTTGCCA Multiple Choice It contains A. It does not include an equal number of As and Ts. It does not include an equal number of Gs and Cs.
The correct answer and explanation is:
The correct answer is: It contains T and not U.
Explanation:
The piece of mRNA provided is: TACCAGGATCACTTTGCCA.
mRNA (messenger RNA) is a type of RNA that is synthesized from a DNA template during the process of transcription. RNA differs from DNA in a few key ways:
- Uracil replaces thymine: In DNA, the bases adenine (A) pairs with thymine (T), cytosine (C) pairs with guanine (G), and guanine (G) pairs with cytosine (C). However, in RNA, the base thymine (T) is replaced by uracil (U). Therefore, instead of thymine, RNA should contain uracil (U) as its counterpart to adenine (A). This means that the presence of T in the given sequence of mRNA is incorrect. It should contain U in place of any T.
- Equal numbers of bases are not required: The statement about an equal number of As and Ts, or Gs and Cs, is not a rule for RNA sequences. In fact, RNA sequences do not need to have an equal number of purines (A and G) and pyrimidines (C and U). The composition of these nucleotides is variable and depends on the genetic code being transcribed from the DNA template. Therefore, the claim about an unequal number of A and T or G and C is irrelevant in this context.
Thus, the only error in the sequence TACCAGGATCACTTTGCCA is the inclusion of the base thymine (T), which should be replaced by uracil (U) in mRNA. Therefore, the correct mRNA sequence should read: UACCAGGAUCACTTTGCCA.
This is a fundamental difference between DNA and RNA, which is crucial in understanding genetic transcription.