21. Pedigree analysis, PCR and genetics Flashcards
what are x linked chromosomes?
the chromosome that determins gender
what are autosomal chromosomes?
chormosomes the affect genotype and phenotypes and DONT determine sex
what are tandem repeats?
DNA codons that are adjacent to each other, they are on a specific loci on a chromosome
what is PCR? (polymerase chain reaction)
a machine that multiples the amount of DNA in short tandem repeats. Its done with test tubes and a machine
what are the three steps of PCR and what do they do?
denaturation- in a PCR machine, heating the DNA molecules to split the hydrogen bonds and make two strands
Annealing- temperature drops and primers link up to the seperated DNA strands so new nucelotides are attached
Extention- DNA polymeras adds nucelotides onto the 3’ end of the nucleotide
what are two useful reasons of polymerase chain reaction?
its specific: only the specific segment on DNA (the target sequence) targeted by the DNA primers is amplified and copied
sensitivity: many copies ofa gene can be made from just one molecule
name four reasons PCR is an important method
- used for parentage tests
- enviornmental sampling
- fossily DNA analysis
- diagnosic tests
what is the difference between DNA replication and PCR?
PCR dosent use helicase, primase enzymes and the need for a cell to do it in.
in PCR, taq polymerase is used instead of DNA polymerase
why dosent PCR need helicase to unwind the DNA double helix?
because during denaturation, the DNA is heated which splits the DNA into two strands
what is important about taq polymerase in PCR?
taq polymerase can withstand high temperatures duirng denaturation which means the enzyme does not need to be replaced after each cycle. DNA polymerase would be denatured at the high temperature
how is PCR so specific? what enzyme is used?
the primer sequence are chosen so they create a hybrid of the DNA ONLY to sequences at opposite ends of the target segment - 3’ end of each strand
