Translation and transcription

Question 1

What is transcription?

Answer 1

where one gene on the DNA is copied into mRNA

Question 2

What is the process of transcription?

Answer 2

• the DNA helix unwinds to expose the basis to act as a template
• only one chain of DNA acts as a template
• like DNA replication, this unwinding and unzipping is catalysed by DNA helicase
• DNA helicase breaks the hydrogen bonds between bases
• free mRNA nucleotides in the nucleus align opposite exposed complementary DNA bases
• the enzyme RNA polymerase bonds together the RNA nucleotides to create a new RNA polymer chain, one entire gene is copied

Question 3

What is the anticodon complimentary to in translation?

Answer 3

the anticodon in tRNA is complimentary to the codon on the mRNA

Question 4

What is the process of translation?

Answer 4

• when the mRNA has left the nucleus, it attaches to the ribosome in the cytoplasm
• the ribosome attaches at the start codon
• the tRNA molecule with the complementary anticodon aligns opposite the mRNA, held in place by the ribosome
• the ribosome will move along the mRNA molecule to enable another complementary tRNA to attach to the next codon on mRNA
• the two amino acids that have been delivered by the tRNA molecule are joined by a peptide bond, this is catalysed by an enzyme and requires ATP
• this continues until the ribosome reaches the stop codon at the end of the mRNA molecule, the amino acid chain (primary structure) then detaches and changes its structure