Transcription

Question 1

What is Transcription?

Answer 1

The process where DNA is used as a template to make mRNA. This happens in the nucleus and is the first step of gene expression.

Question 2

What happens during initiation in transcription?

Answer 2

RNA polymerase binds to the promoter region, unwinds the DNA, and prepares to start making mRNA.

Promoter Region make sure that all the desired DNA is copied

Question 3

What happens during elongation in transcription?

Answer 3

RNA polymerase builds mRNA by reading the template DNA strand, adding RNA bases in the 5’ to 3’ direction.

Question 4

How is elongation different from DNA replication?

Answer 4

Transcription doesn’t need a primer, uses only one DNA strand, and uses uracil (U) instead of thymine (T).

Question 5

What happens during termination in transcription?

Answer 5

RNA polymerase reads a terminator sequence and stops transcribing; the mRNA is released.

Question 6

What is the difference between the coding strand and template strand?

Answer 6

The template strand is used to build mRNA (it’s complementary to mRNA). The coding strand matches the mRNA, except it has T instead of U.

Question 7

What is the primary transcript?

Answer 7

The unprocessed mRNA made right after transcription.

Question 8

What are the 3 main post-transcriptional modifications?

Answer 8

5’ cap:
A methylated G added to the 5’ end. Protects mRNA and helps it attach to ribosomes
Poly-A tail:
Adenines added to the 3’ end. Increases stability and protects important info
RNA splicing:
Introns removed; exons joined.Makes a clean, readable mRNA strand

Question 9

What are introns and exons?

Answer 9

Introns are non-coding sections removed; exons are coding sections that are kept.

Question 10

What are spliceosomes and why are they important?

Answer 10

Proteins that remove introns and connect exons so the mRNA can be translated correctly.