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:
ChatGPT said:
The correct answer is: B. It does not include an equal number of Gs and Cs.
Explanation
Messenger RNA (mRNA) is a single-stranded molecule transcribed from DNA, which carries genetic instructions from the nucleus to the ribosome for protein synthesis. Unlike double-stranded DNA, mRNA does not require base pairing rules to maintain equal numbers of complementary bases like adenine (A) with thymine (T), or cytosine (C) with guanine (G). However, understanding base composition can still highlight abnormalities or imbalances in nucleotide proportions, which may suggest mutations or errors in transcription.
Let’s analyze the provided mRNA sequence:
TACCAGGATCACTTTGCCA
First, count the nucleotides:
- A (Adenine) = 4
- U (Uracil) is not present because the sequence uses T (Thymine) — suggesting this might be pre-mRNA or a transcription error.
- T (Thymine) = 5
- C (Cytosine) = 4
- G (Guanine) = 3
Now consider the choices:
A. It does not include an equal number of As and Ts.
There are 4 As and 5 Ts. While not equal, this is not necessarily an error in mRNA, since it is single-stranded. The rule of equal As and Ts applies to double-stranded DNA due to base pairing.
B. It does not include an equal number of Gs and Cs.
There are 3 Gs and 4 Cs. This might be significant because in some regions of the genome, especially in coding sequences or GC-rich regions, an imbalance could affect RNA stability or structure. Still, in single-stranded mRNA, an exact 1:1 G to C ratio is not required, but an imbalance could suggest something to investigate further.
Given the question context and structure, B is more appropriate, since G-C pairing is stronger due to triple hydrogen bonding, and an imbalance can potentially influence RNA folding and function.
Note: Also, the presence of T instead of U is incorrect for mRNA. Proper mRNA should use uracil (U) instead of thymine (T).
