What term describes the process of producing the RNA strand from a DNA template?
A.
Transcription.
B.
Recombination.
C.
Replication.
D.
Synthesis.
The correct answer and Explanation is :
The correct answer is A. Transcription.
Transcription is the process by which an RNA strand is synthesized from a DNA template. This fundamental biological process is crucial for the expression of genetic information stored in DNA.
Here’s a detailed explanation of transcription:
- Initiation: Transcription begins when the enzyme RNA polymerase binds to a specific region of the DNA known as the promoter. The promoter is located upstream of the gene to be transcribed and serves as a signal for RNA polymerase to start the transcription process.
- Unwinding of DNA: Once RNA polymerase attaches to the promoter, it causes the DNA double helix to unwind and separate into two single strands. One of these strands, called the template strand or antisense strand, serves as the blueprint for RNA synthesis.
- Elongation: During the elongation phase, RNA polymerase moves along the DNA template strand in a 3’ to 5’ direction, synthesizing a complementary RNA strand in the 5’ to 3’ direction. The RNA polymerase adds nucleotides one by one to the growing RNA strand, matching the base pairs with the DNA template strand (adenine pairs with uracil in RNA, and cytosine pairs with guanine).
- Termination: Transcription continues until RNA polymerase reaches a termination signal or terminator sequence in the DNA. This sequence signals the end of the gene, prompting RNA polymerase to detach from the DNA and release the newly synthesized RNA strand.
- Processing: In eukaryotic cells, the primary RNA transcript (pre-mRNA) undergoes several modifications before it becomes a mature messenger RNA (mRNA). These modifications include 5’ capping, 3’ polyadenylation, and splicing to remove introns and join exons together.
Transcription is a vital step in gene expression, converting genetic information from DNA into RNA, which can then be translated into proteins. This process is distinct from replication, which duplicates DNA, recombination, which involves the exchange of genetic material, and synthesis, which is a more general term for the creation of molecules.