In a DNA, the coding region reads 5’-CGT-3’. The RNA code will be:
**Core Concept**
The process of transcription from DNA to RNA involves base pairing rules, where A pairs with U (in RNA), G pairs with C, and C pairs with G. However, during transcription, the RNA has an opposite orientation to the DNA template, meaning the RNA sequence is complementary to the DNA template strand.
**Why the Correct Answer is Right**
To find the RNA sequence, we need to complement the given DNA template sequence 5'-CGT-3'. This involves making the correct base pairings: C with G, G with C, and T with A (since in RNA, T is replaced by U). Therefore, the RNA sequence will be 5'-CGA-3', where C pairs with G, G pairs with C, and T pairs with A.
**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because it doesn't follow the base pairing rules and the RNA orientation.
* **Option B:** Incorrect because it doesn't correctly complement the DNA template sequence.
* **Option C:** Incorrect because it doesn't follow the correct base pairing rules and the RNA orientation.
**Clinical Pearl / High-Yield Fact**
When transcribing DNA to RNA, the RNA sequence is complementary to the DNA template strand and has an opposite orientation. It's essential to remember the base pairing rules (A-U, G-C, and C-G) to accurately predict the RNA sequence.
**Correct Answer: B. 5'-CGA-3'**