Summarise the process of DNA replication.

- DNA helicase breaks hydrogen bonds between base pairs forming two strands - each original strand acts as a template strand - free DNA nucleotides pair with exposed bases on the template strands via complementary base pairing - DNA polymerase catalyses the formation of phosphodiester bonds between adjacent nucleotides forming the sugar phosphate backbones - hydrogen bonds form between complementary bases - two identical DNA molecules are produced

Summarise the process of protein synthesis.

Transcription: - DNA helicase breaks hydrogen bonds between base pairs forming two strands - one of the original strands acts as a template strans - free RNA nucleotides pair with exposed bases on the template strands via complementary base pairing - RNA polymerase catalyses the formation of phosphodiester bonds between adjacent nucleotides forming the sugar phosphate backbone of the mRNA molecule - the mRNA molecule detaches from the DNA and leaves the nucleus through a nuclear pore to go to the ribosome for translation Translation: - ribosome attaches to mRNA - a tRNA molecule arrives carrying an amino acid and its anticodon pairs with the complementary codon on the mRNA - this happens again and the amino acids attached to the two tRNA molecules join via a peptide bond - the tRNA molecules detach from the amino acids - this process is repeated until a stop codon is reached on the mRNA

What are the features of the genetic code and what do they mean?

non-overlapping - triplets don't share bases degenerate - more than one triplet codes for the same amino acid (reduces the effect of mutations)