Protein synthesis

Question 1

Describe the process of transcription

Answer 1

DNA unwinds and unzips using helicase
RNA polymerase attaches to the DNA at the beginning of the sequence to be copied
RNA nucleotides align themselves with complimentary DNA bases
RNA polymerase moves along the DNA strand adding more nucleotides to from an mRNA strand
The mRNA strand leaves the nucleus and attaches itself to a ribosome

Question 2

Describe the process of translation

Answer 2

The ribosome reads the mRNA strand
tRNA molecules carry amino acids and attach them to the mRNA strands to match the triplet codes on it
Complimentary anticodon - codon bases align and are held together by the ribsome at the attachment site, anticodon-codon complexes form
Peptide bonds form between amino acids, creating a polypeptide chain

Question 3

What is the difference between pre-mRNA and mRNA

Answer 3

Pre-mRNA contains introns which at non-coding sequences of DNA. These are removed and so mRNA is composed of exons.

Question 4

What are start and stop codons

Answer 4

Triplet codes that code for the production of amino acids that either start or end a polypeptide chain