electrophoresis Flashcards
1
Q
where do restriction enzymes come from
A
bacteria
2
Q
blunt vs sticky ends
A
sticky: have an overhang and a strong attraction blunt: cuts directly down
3
Q
enzyme used to join pieces DNA together
A
ligase
4
Q
why sticky ends are preferred
A
- attach in one direction - attract each other - blunt ends aren’t going to works because they can flip and not match up correctly
5
Q
in which direction do the fragments move
A
-down towards the positive ends because phosphates are negative and opposites attract
6
Q
main steps of electrophoresis
A
- dna is cut with restriction enzymes
- gel is placed in the gel chamber with the well end at the negative electrode side
- the buffer solution is added to cover the gel
- dna samples are added into the wells
- electric current is applied
- due to negative charge the dna moves to the positive electrode
- the dna strands are seperated according to size and mass
- the smaller strands will travel more easily through the gel = further
7
Q
what are STR and how are they useful
A
- short tandem repeat - DNA sequence made up of 2-12 nucleotides repeated several times in a row on the dan strand - useful as it can help compare specific loci from 2 or more dan samples - can identify humans - loci = location of a gene
8
Q
bacteria
A
where do restriction enzymes come from
9
Q
ligase
A
enzyme used to join pieces DNA together
