Protein synthesis

Question 1

Describe transcription

Answer 1

H bonds between base pairs break and the DNA unwinds
Free nucleotides line up and complementary base pairs form
RNA polymerase attaches to the templacte strand to form phosphodiester bonds between the bases on the strand
This produces mRNA strand
mRNA detaches from DNa and leaves through the nuclear envelope and the DNA zips up

Question 2

Describe mRNA splicing

Answer 2

This occurs between translation and transcription
mRNA is efited by removing no coding regions called introns and remaining exons are spliced together
several proteins can be formed from 1 strand if its spliced differently

Question 3

Describe translation

Answer 3

mRNA attaches to ribosomes on rough ER
tRNA carries an amino acid and an anticodon complementary to an mRNA codon for an amino acid
First codon, start codon is AUG
tRNA molecule moves towards AUG codon and H bonds form
when a second tRNA molecule bonds to mRNA a peptide bod forms between 2 amino acids via a condensation reaction
Ribosome moves along the mRNA and first tRNA is released