Manipulating Genomes Flashcards
Define DNA sequencing
working out the sequence of bases in a strand of DNA
Define genome
all the genetic material of an organism
Define intron
a region of non-coding DNA or RNA
Define exon
a sequence of DNA that codes for an amino acid sequence
Define DNA profiling
producing an image of the patterns in the non-coding DNA of an individual
Define polymerase chain reaction
a process by which a small sample of DNA can be amplified using specific enzymes and temperature changes
Define restriction endonucleases
enzymes that chop a strand of DNA into small pieces
Define electrophoresis
a type of chromatography that relies on the way charged particles move through a gel under the influence of an electric current and it is used to separate nucleic acid fragments or proteins
Define minisatellite
sequences of 20-25 base pairs will be repeated from 50 to several hundred times (variable number of Tandem repeats VNTR’s)
Define microsatellite
a region of 2-4 bases repeated 5-15 times (short Tandem repeats STR’s)
Define telomere
the distinctive cap-like structure present at the end of each strand of DNA and provide protection against DNA damage
Define centromere
the region at which 2 chromatids are held together
What is the purpose of PCR?
it can take a fragment of DNA and produce millions of copies in a short period of time - it is a method of amplifying DNA
What is in a PCR reaction mixture?
DNA, free nucleotides, primers and Taq polymerase
What is the role of DNA primers in PCR?
They are artificial complimentary sequences of DNA that latch onto the desired sequences so that DNA polymerase can attach to the strand and begin synthesising a complimentary strand.
What is the role of Taq DNA polymerase in PCR?
It is a temperature resistant enzyme responsible for DNA replication by assembling nucleotides along a complimentary strand.
What is the role of fluorescent markers in PCR?
Allows you to see how much DNA has been amplified
What are primers complimentary to in PCR?
primers are complimentary to the sequence at the beginning of the piece of DNA you want to look at
What temperature does the denaturing stage in PCR take place at?
95 degrees C
What temperature does the annealing stage of PCR take place at?
55 degrees C
What temperature does the extension stage of PCR take place at?
72 degrees C
What happens in the denaturing stage of PCR?
this stage breaks the hydrogen bonds allowing the DNA strands to separate
What happens during the annealing stage of PCR?
the solution is cooled enough to allow the DNA primers to attach at the start of the STR’s
What happens during the extension stage of PCR?
Taq polymerase attaches the nucleotides to synthesise a complimentary strand