Describe three ways of synthesising DNA fragments and how they are amplified:

I would ask the tutee when considering an answer to divide the question in two to ensure not one part of it is overlooked but give the answer as a whole.Part 1 Conversion of mRNA into cDNA using reverse transcriptase that synthesises a strand of complimentary bases.
The two strands hybridise forming the double stranded cDNA.Using restriction enzymes that recognise and cleave palindromic sequences of DNA. The restriction enzyme used should cut up and downstream of the gene of interest, leaving an isolated fragment containing said gene of interest.
Creating the gene in a 'gene machine'. This machine synthesises a pre-determined poly-nucleotide sequence (e.g. using LAMP/MDA).
Part 2-DNA fragments can be amplified (produce more copies of) by either in vitro or in vivo methods.
In vivo, means 'in the living', so fragment is amplified in cells. This occurs by inserting the fragment into an expression vector, transforming it into a bacterial cell which upon multiplying produces more copies of the gene.
In vitro means 'in the glass' so is laboratory not cell based. The most common in vitro method for DNA amplification is PCR (the Polymerase Chain Reaction).