Unit 1- Key area 1.2

Question 1

How does DNA make identical copies of itself?

Answer 1

DNA is the hereditary material of cells. It can make identical copies of itself by a process called replication. DNA replicates before cell division and copies are passed onto daughter cells.

Question 2

Why is DNA replication important?

Answer 2

DNA replication is important because it ensures that identical copies of the genetic information of a species are passed on from cell to cell and from generation to generation.

Question 3

What is PCR?

Answer 3

The polymerase chain reaction is a laboratory technique that is used to produce billions of copies of specific target sequences of DNA. The technique is carried out in vitro which means that is happens outside the body of the organism in laboratory apparatus, and involves cycles of heating and cooling.

Question 4

What is negative control?

Answer 4

The PCR procedure is set up but the DNA sample of interest is left out and there should be no amplification of DNA so any amplified DNA found must be caused by contamination.

Question 5

What is positive control?

Answer 5

The PCR procedure is set up but with a DNA sample which is already known to respond to amplification so any problems with the result is due to experimental flaws involving primer, polymerase, or the nucleotide supply.

Question 6

What are examples of applications of PCR?

Answer 6

In forensics it can be used to amplify tiny quantities of DNA from biological sources such as blood or semen. This allows conformation of the presence of individuals at crime scenes from small samples of biological material.
Another common application is in amplifying DNA in studies of related species to show their true place in evolution.