chapter 6/7 topic 4 structure, rep, recom/mutation

pp 5-9 whiteboard then make flashcards , pp 21 - 24 potentiel long a pp 30-end whiteboard wnser??

what is a tetrad

a group of 4 chromatids formed when a pair of homologous chromosomes’ come together during prophase 1 in meiosis

homologous recombination helps to increase ______

genetic diversity

what is site specific recombination

crossing over that occurs between two specific short DNA target sites

what is the significance of recombinase in site specific recombination

it is the protein that catalyzes the breakage and joining of DNA ends

what is excision

the process of removing a segment of DNA from a larger DNA molecule

what is forward mutation

changes in DNA sequence that causes a wildtype allele to change into a different allele

what is a reverse mutation / reversion

changes in DNA sequence that cause a mutant allele to change back to wildtype

what is a substitution mutation

when a base at a certain location is replaced by one of the other three bases

what is a deletion mutation

when one or more base(s) are removed

what is an insertion mutation

when one or more base(s) are added

the rate of _____ mutation is usually much higher than the rate of _______ mutation.

forward, reverse

what drives teh majority of new mutations in humans and why

sperm because it exhibits a higher mutation rate than eggs

what is depurination, what does it lead to in terms of mutation probability

the process of purine base hydrolysis which leads to apurinic sites which does not specify a base increasing probability of mutation

what is deamination

the removal of an amino group from a nucleobase like cytosine, changing it to uracil ( transitioning C to T)

how can X-rays cause spontaneous mutation

breaks the sugar phosphate backbone which leads to breakage in DNA strands

how does UV radiation cause spontaneous mutation

causes thymine’s to form dimers which leads to substitutions during replication

what are trinucleotide repeat diseases

a disease caused by the repetition of a certain triplet sequence

what defines a poly q trinucleotide repeat disease

the repeated triplet is always CAG

what defines a non-poly q trinucleotide sequence

the repeated triplet can be CGG, CTG, GCC, GAA

What is a mutagen

a physical or chemical agent that raises the frequency of mutations above spontaneous rate

how do base analogs operate as mutagens

a mutagen that is so similar in chemical structure to the normal base that they are incorporated into backbone during replication causing a substitution mutation

what impact do somatic mutations have on human health

mutates genes that help to regulate the cell cycle which can lead to cancer. aka carcinogens