The replication of DNA is semi-conservative and depends on complementary base pairing.

• Describe the meaning of “semi-conservative” in relation to DNA replication.

• Explain the role of complementary base pairing in DNA replication.

Helicase unwinds the double helix and separates the two strands by breaking hydrogen bonds.

• State why DNA strands must be separated prior to replication.

• Outline two functions of helicase.

• State the role of the origin of replication in DNA replication.

• Contrast the number of origins in prokaryotic cells to the number in eukaryotic cells.

DNA polymerase links nucleotides together to form a new strand, using the pre-existing strand as a template. [The different types of DNA polymerase do not need to be distinguished.]

• Describe the movement of DNA polymerase along the DNA template strand.

• Describe the action of DNA polymerase III in pairing nucleotides during DNA replication.

Transcription is the synthesis of mRNA copied from the DNA base sequences by RNA polymerase.

• Define transcription.

• Outline the process of transcription, including the role of RNA polymerase and complementary base pairing.

• Identify the sense and antisense strands of DNA given a diagram of translation.

Translation is the synthesis of polypeptides on ribosomes.

• Define translation.

• State the location of translation in the cell.

The amino acid sequence of polypeptides is determined by mRNA according to the genetic code.

Codons of three bases on mRNA correspond to one amino acid in a polypeptide.

Translation depends on complementary base pairing between codons on mRNA and anticodons on tRNA.

Use of Taq DNA polymerase to produce multiple copies of DNA rapidly by the polymerase chain reaction (PCR).

Production of human insulin in bacteria as an example of the universality of the genetic code allowing gene transfer between species.

Use a table of the genetic code to deduce which codon(s) corresponds to which amino acid.

Analysis of Meselson and Stahl’s results to obtain support for the theory of semi-conservative replication of DNA.

Use a table of mRNA codons and their corresponding amino acids to deduce the sequence of amino acids coded by a short mRNA strand of known base sequence.

Deducing the DNA base sequence for the mRNA strand.