Key Area 3: Transcription

Question 1

What is a codon?

Answer 1

A triplet of bases in mRNA

Question 2

What is an anti-codon?

Answer 2

A triplet of bases in tRNA

Question 3

What is the purpose of RNA polymerase in transcription?

Answer 3

To break hydrogen bonds and form the backbone

Question 4

What are the stages of transcription?

Answer 4

• DNA unwinds and hydrogen bonds break between bases using RNA polymerase
• RNA nucleotides pair up with complementary DNA bases
• RNA polymerase forms sugar-phosphate backbone to form mRNA strand (primary transcript)
• introns are removed and exons are spliced together (nature mRNA)
• mRNA leaves nucleus into cytoplasm for translation