Molecular Genetics-2️⃣Transcription

Question 1

Transcription in mRNA

What is The Process of Stage 1: Initiation

Purpose: To take DNA into a complemetary mRNA molecule.

Answer 1

1. RNA Polymerase binds to the promoter that is often has a lot of Ts and As (TATA box). The promoter is very similar to the origin in dna replication.
   * Template/antisense strand: One strand is transcribed
   * Coding/sense strand: opposite strand that’s not transcribed

Enzymes: RNA Polymerase

Transcription–>Promoter=Replication–> Origin|Enzyme: RNA Polymerase

Question 2

Transcription in mRNA

What is The Process of Stage 2: Elongation?

Answer 2

1. RNA Polymerase builds the
   single-stranded mRNA from 5’ to 3’
2. Another RNA Polymerase binds to the promoter so more copies can be made from one gene.

Transcription—>doesn’t need primer|Replication–>needs primer

Question 3

What is the process of Stage 3: Termination?

Answer 3

1. RNA Polymerase recognizes a terminator sequence to stop transcribing
2. mRNA & RNA Polymerase are released

Question 4

What are some post-transcriptional modifications?

Answer 4

• Capping + Tailing:
  5’ cap is added to protect mRNA from enzyme digestion & help with initating translation. A poly-A tail is added to protect mRNA from degradtion and helps to terminate translation.
• Removing introns:
  Introns must be removed so the protein folds and functions properly.
  Removed through splicing: SNRPS (particles of RNA and protein) cut the introns where they meet with exons. Results in mature mRNA and introns stay in nucleus, nucleotides are recycled.
• Introns: non-coding regions of a gene
• Exons: Segments of RNA that code for specific protein (expressed)