MUTATIONS in JEANS EXAM 3

damn

mutation define

why important

when sequence of DNA within a gene is altered in a permanent way. it could be a base substitution or removal or adding of one or more base pairs 

important: they give new gene variation which can help give new adaptations to their enviro over time 

point mutation def

aka 

any mutation that affects a single NT position

aka base substitutions, single base deletions or single base insertions

base subsitution is a type of blank. the def is 

point mutation. one base replaced with another 

transitions and transversions are types of 

silent mutations 

missense mutations 

base sub

frameshift mutations 

base sub which is a type of point mutation

transition vs transversion def 

sition= same to same. pyr to pyr or pure to pure 

version= different to different 

true or false - transversions are more frequent than transitions 

false. they are much less freq cuz once there is a transversions there is a big base pair mismatch the distorts the DNA double helix. the DNA pol will recongs this and the incorrect base is removed 

t or f: mutations can involve addition or deletion of short seqs of DNA

t

under the structure category of additions/deletions- what is inframe vs frameshift

inframe= addition of three or multiple of 3 nts

frameshift= involve addition or deletion of nt not div by 3 so it means the reading frame shifts so that the transL of mRNA results in diff amino acid seq downstream of mutation 

effects of poiNT mutations include 

silent mutations= when a change that do not alter AA seq of polypep even tho base seq has changed. this is cuz genetic code is degernate- meaning theres a bunch of ways to get to the same amino acid.

when this happens, silent mutations usually occur at certain bases within a codon aka the the third base 

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missense= base stubbies for which an amino acid change DOES happen 

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nonsense mutation= change from a codon that makes an AA to a stop codon. basically makes a premature stop codon

neutral mutation

are silent mutations apart of this too

when a missense mutation has no detectable effect on tein func

yes 

patient A shows the the missense mutation subbed glumatic acid for aspartic acid. this is a

frameshift

neutral mutation

negative mutation 

none of these 

neutral. this is because if the OG AA has the similar chemistry to the NEW AA, then it will be neutral. so here, both AA are neg charged and it will be neutral 

trinucleotide repeat expansion mutation def 

basically in some genes normally there will be an abnormal expansion of repetitive sequences. so for example the htt gene has 5 repeats of CAG.

then the mutation happens. now the HTT has 20 repeats of CAG 

how mutations ocurr in the promoter might have any influence in the protein product HUH

mutations in core promter change levels of gene expression where up mutations increase expression and down mutation decrease expression

ex= mutations can decrease the rate of trans of spe genes. or mutations that increase expression of spe genes 

what mutations are involved in the dev of CF

which of the most common mutations

mutations of CF= deletion is the most common. theres also frame shift, missense and promoter mutation

common one= the inframe deletion called F508del. this deletes 3 Nts aka one amino acid at position 508.

what causes CF

what protein is respon

what does the protein do in cells 

cause= mutations in the cftr gene which leads to production of thick sticky mucus

protein= CFTR

tein func= is a channel that moves cl ions across cell membrane which balances water and salt in bodily functions. it helps secretions be thin

PHE508DEL meaning

508th triplet codon that is usually phe gets deleted. it is now three NT shorter and is aka deletion inframe mutation

GLN493TER meaning

single NT replaced with premature stop. this is nonsense mutation that makes shorter tein

t or f: a nonsense mutation always results in shorter tein

yes

ASP110HIS meaning

single base change causes aspartic acid at position 110 to be replaced by histidine. the mRNA is unchanged in length but the protein is disrupted in folding

2-bp ins 2566AT 

a 2 BP insertion (AT) at NT 2566 shifts the reading frame because its not a multiple of 3. the altered reading frame will 

Pro301LeufsTer7

the original Pro at position 301 is replaced by Leu but not cuz of simple substitution. this is because the reading frame shifted due to an insertion or deletion in the earlier DNA seq. so now after the frameshifts, all downstream AAs are wrong and this starts at now leu at 301.

finally the new stop codon will appear SEVEN amino acids later, that’s what the number will mean