WEEK 14 (Recombinant DNA technology)

Question 1

Describe the process of Recombinant DNA technology

Answer 1

1) Isolate eukaryotic mRNA of interest
2) Add reverse transcriptase to produce complementary DNA
3) Insert cDNA fragments into bacterial plasmids containing antibiotic resistance genes
4) Insert recombinant plasmid into bacteria
5) Surviving bacteria on antibiotic medium produce cloned DNA

Question 2

What does a Genomic library consist of?

Answer 2

Many overlapping fragments of the genome with at least one copy of every DNA sequence in an organism’s chromosomes

Question 3

How is the Genomic Library made?

Answer 3

Chromosomal DNA is extracted from cells or tissues and cut randomly with RESTRICTION ENZYMES -> Resulting fragments are inserted into VECTORS which may contain more than one gene or only a portion of a gene -> Libraries will contain CODING and NONCODING segments of DNA

Question 4

What makes Complementary DNA (cDNA) libraries more advantageous than genomic libraries?

Answer 4

cDNA libraries contain cDNA (made from mRNA molecules isolated from cultured cells or a tissue sample) -> cDNA libraries provide a SNAPSHOT/CATALOG of just the genes that were transcriptionally active in a tissue at a particular time -> Useful for identifying and studying genes expressed in certain cells or tissues under certain conditions

Question 5

What is the Polymerase chain reaction?

Answer 5

A Molecular biology lab procedure used to amplify a desired fragment of DNA

[Useful as a diagnostic tool]

Question 6

Describe the Polymerase chain reaction

Answer 6

1) DENATURATION - DNA is heated to 95 degrees Celsius to separate the strands
2) ANNEALING - Sample is cooled to 55 degrees Celsius -> DNA primers, a heat-stable DNA polymerase and DEOXYNUCLEOTIDE TRIPHOSPHATES (dNTPs) are added -> DNA primers anneal to the specific sequence to be amplified on each strand
3) ELONGATION - Temperature is increased to 72 degrees Celsius -> DNA polymerase attaches dNTPs to the strand to replicate the sequence after each primer

[Heating and cooling cycles continue until the amount of DNA is sufficient]

Question 7

What genes on activation produces malignant neoplasm?

Answer 7

Oncogenes

Question 8

Which property of P53 enables it to prevent the development of cancer?

Answer 8

It prevents replication of cells with damaged DNA

Question 9

Migration of cancerous cells from the site of origin to the other part of the body forming secondary tumours is called __________________

Answer 9

Diapedesis

Question 10

What can be coded by a tumour-suppressor gene?

Answer 10

A protein that helps prevent progression through cell cycle