2. RNA and protein synthesis

Question 1

transcription

Answer 1

1. RNA polymerase breaks H bonds -> strands sepearate -> exposed bases/template
2. free RNA nucleotides attracted to exposed bases. specific complimentary base pairing.
3. RNA polymerase joins free nucleotides = mRNA molecule
4. when RNA polymerase reaches stop signal stops making mRNA and detaches
5. mRNA moves out through nucleuar pore and attaches to a ribosome

Question 2

transcription in eukaryotes

Answer 2

introns and exons copied (pre-mRNA)

splicing - introns removed, exons joined (in nucleus)

Question 3

transcription in prokaryotes

Answer 3

mRNA produced directly from DNA = no splicing

Question 4

translation

Answer 4

1. m RNA attaches to ribosome. tRNA carry amino acids to it. ATP = energy needed for bond between tRNA and amino acid to form
2. tRNA with anticodon complimentary to 1st codon on mRNA attaches (specific base pairing)
3. 2nd tRNA attaches to next codon. 2 amino acids join to form peptide bond. 1st tRNA molecule leave leaving amino acid behind
4. 3rd tRNA molecule joins and so on.. polypeptide chain formed until there is a stop signal