DNA

Question 1

How can small changes in a DNA sequence affect the individuals and how sequencing a person’s genome could influence their medical treatments?

Answer 1

DNA has 4 different bases and changes in the DNA are mutations, resulting in different alleles for these genes, affecting the phenotype and producing variation.

DNA sequencing for the individual allows identification genetic diseases and the risk of developing diseases. Knowing that a disease could develop allows the individual to modify their lifestyle to reduce risk.

Impact on medical treatment includes determining the location of genes/ the function of proteins. We have a better understanding of some diseases, allowing tailor-made medical treatments/personalised medicines to be provided.

Question 2

Structure of DNA

Answer 2

-polymer
-four bases (A, T, C, G)
-complementary base pairs are AT and C-G
-weak hydrogen bonds join bases
-two strands
-double helix
-sugar phosphate backbone

Question 3

DNA extraction method

Answer 3

-crush up/ grind cells
-add detergent/ protease (breaks down proteins in the cell membrane)
-heat in a water bath (to about 60°C)
-filter the mixture to remove insoluble material
-add to ice cold ethanol (to precipitate the DNA)
-DNA forms as a white precipitate

Question 4

Nucleotide

Answer 4

Phosphate—Sugar—Base