6.3 Manipulating Genomes

Question 1

What is a PCR

Answer 1

PCR= polymerase chain reaction

• a method of artificially amplifying copying DNA to get many copies of the Same sample
• used to make enough DNA for testing

Question 2

DNA primers

Answer 2

10-20 dna bases are single stranded
-used for sequencing the PCR to bind to sections of dna so that DNA polymerase can bind (DNA polymerase can’t bind to single strands

Question 3

PCR key steps and temps

Answer 3

Denaturation-95 degrees (splits the DNA)
Annealing -55 degrees (when complentary base pairs come together)
Elongation-72degrees ( temp when DNA polymerase builds the new strand)

Question 4

PCR method

Answer 4

• mix sample of DNA with free DNA nucleotides, primers and magnesium ions and the enzyme TAQ polymerase
• heat to 94-96 to break hydrogen bonds and to make the dna 2 single strands
• then cool to 68 so the primers can connect the hydrogen bonds (annealing)
• then the TAQ bind the end where the double strand is
• raise temp to 72+
• then the TAQ builds the strand in the 5’ to 3’ direction
• repeat process for more

Question 5

Benefits of human genome project

Answer 5

Improved genetic testing 
Location of genes that might be linked to increase chances of inheriting disease 
New gene therapy
Personalised medicines 
Synthetic biology

Question 6

Comparing genomes between species

Answer 6

• evolutionary relationships can be explored by considering the similarities in the genomes of two species and beneficial genes are preserved by evolution
• identify genes which have been altered to give rise to differences between organisms
• the identification of genes common to most living things can give clues as to the relative importance of these genes to life
• difference in gene interaction leads to a difference in proteins
• medical research can be done by comparing a genome of pathogenic and non pathogenic bacteria to identify the genes responsible