Not product of transcriptiona) tRNAb) mRNAc) rRNAd) cDNAe) New strand of DNA
**Core Concept**
Transcription is the process of creating a complementary RNA copy from a DNA template. This process is crucial for gene expression and involves the synthesis of various types of RNA molecules. Understanding the different types of RNA and their roles in transcription is essential for grasping this concept.
**Why the Correct Answer is Right**
The correct answer is the new strand of DNA, which is not a product of transcription. During transcription, RNA polymerase synthesizes a complementary RNA strand from a DNA template. The RNA strand is complementary to one of the DNA strands, not identical to it. The correct answer refers to the original DNA strand that serves as a template for transcription.
**Why Each Wrong Option is Incorrect**
* **Option A:** tRNA (transfer RNA) is a type of RNA that carries amino acids to the ribosome during protein synthesis. While tRNA is involved in the translation process, it is not a direct product of transcription.
* **Option B:** mRNA (messenger RNA) is a type of RNA that carries genetic information from DNA to the ribosome for protein synthesis. mRNA is indeed a product of transcription, but the question asks for what is not a product of transcription.
* **Option C:** rRNA (ribosomal RNA) is a type of RNA that makes up a significant portion of the ribosome. Like tRNA, rRNA is involved in protein synthesis and is not a direct product of transcription.
* **Option D:** cDNA (complementary DNA) is a type of DNA that is synthesized from an RNA template using the enzyme reverse transcriptase. cDNA is not a product of transcription, but rather a product of reverse transcription.
**Clinical Pearl / High-Yield Fact**
One key concept to remember is that transcription involves the synthesis of a complementary RNA strand from a DNA template, whereas reverse transcription involves the synthesis of a complementary DNA strand from an RNA template.
**Correct Answer: e. New strand of DNA**