Recombinant DNA technology - producing fragments

Question 1

What is recombinant DNA technology?

Answer 1

The transfer of fragments of DNA from one organism, or species, to another.

Question 2

What property of DNA allows recombinant DNA technology to happen? Explain why.

Answer 2

The genetic code is universal, as are the transcription and translation mechanisms, so the transferred DNA can be transcribed into mRNA, then translated into polypeptides within cells of the recipient organism. This organism is now transgenic.

Question 3

What is the role of reverse transcriptase in recombinant DNA technology?

Answer 3

It produces cDNA using mRNA.

Question 4

How is a DNA double helix produced from cDNA.

Answer 4

DNA polymerase joins adjacent DNA nucleotides in a phosphodiester bond to produce the complimentary strand of DNA.

Question 5

What is the role of restriction endonucleases in making DNA fragments?

Answer 5

The enzymes used to cut a fragment of DNA containing the desired gene from the organisms DNA.

Question 6

Why is it an advantage to produce DNA fragments using mRNA and reverse transcriptase, than cutting a gene out using restriction enzymes?

Answer 6

mRNA does not contain introns, so the cDNA produced will only contain exons. Some organisms (prokaryotes) can’t splice introns out of mRNA; There is much more mRNA in a cell than DNA for a particular protein; mRNA will be found in the cell that specifically makes the protein;

Question 7

What is a gene machine?

Answer 7

An automated way of producing DNA fragments with the correct DNA base sequence.

Question 8

What is the benefit of using the gene machine to produce a DNA fragment, rather than using reserve transcriptase?

Answer 8

There are more steps involved in isolating mRNA; Faster to use gene machine than all the enzyme-catalysed reactions involving reverse transcriptase;