Lecture 18 - Gel electrophoresis, PCR, Restriction fragment analyse, genome sequencing

What is a genome?

Comeplete set of DNA, including all its genes

What is genome sequencing?

Determining the exact sequence of all the millions of bases making up the DNA of an organism

What is the purpose of polymerase chain reaction

To produce a large amount of DNA that is identical to the small sample by repeatedly heating and cooling the sample to allow DNA denaturation, primer binding, and DNA synthesis.

What is the first process of Polymerase chain reaction?

Denaturation - Heat is used to break the hydrogen bonds of DNA causing the double helix to seperate into single strands

What is the second process of the polymerisation chain reaction

Annealing - The temperature must drop and the short DNA primers bind to the complimentary sequences on the single-stranded DNA.

Primers mark the starting point for copying

What is the third process of the polymerase chain reaction?

Extension - The temperature is raised to the optimum low for Taq DNA polymerase. The enzyme adds nucleotides to the primers, building new strands of DNA

Once DNA cloning has produced a large quantity of DNA what must happen? And what are the 2 techniques?

Laboratory techniques can be applied to analyse the DNA.

What is gel electrophoresis?

Using a gel that acts separates nucleic acid or proteins based on their size and charge

How does gel electrophoresis work?

Sample are loaded into wells in agarose gel. When the current is turned on, the negatively charged DNA molecules move towards the positive electrode, with shorter molecules moving faster than longer ones.

Once the current is turned off what happens?

After the current is turned off, a DNA-binding dye is added, revealing the seperate bonds to which it binds

What is restriction fragment analysis used for?

Used to study differences in DNA by cutting and comparing two different DNA molecules

Step for restriction fragments analysis

Cut specific sequence in the DNA with restriction enzymes. Then gel electrophoresis is used to seperate the fragments.

What is genome sequencing?

Process of determining the exact order of all the dna bases (ATCG) in a genome