Mutations #7

Question 1

mutation

Answer 1

is a permanent change of the nucleotide sequence of the genome of an organism

Question 2

cause of mutations?

Answer 2

~damage to the nucleic acid that is not repaired
~errors during replications
~insertions/deletions of segments of DNA by mobile genetic elements

Question 3

mutations are classified by their

Answer 3

structure 
function
fitness

Question 4

what are the 3 structures of mutations

Answer 4

genomic mutations - # of chromosomes varied
chromosomic mutations - different structure of chromosomes
gene mutations - variation in structure of a gene at a nucleotide level

Question 5

what are the 3 kinds of point mutations

Answer 5

base substitutions, indels (base insertions/ base deletions )

Question 6

what are the 2 kinds of base substitutions

Answer 6

transitions - purine to purine/ pyrimidine to pyrimidine

transversion - purine to pyrimidine

Question 7

what are the types of mutations

Answer 7

silent, missence, nonsense, elongation

Question 8

missence

Answer 8

is a point mutation that results in a different amino acid being produced

Question 9

the consequence of a missence mutation depend on

Answer 9

~ the type of aa change
~the conservation observe among species
~the position in he 3D structure of the protein

Question 10

nonsense mutation

Answer 10

is a point mutation that results in an introduction of a premature stop codon…..could lead to activation of nonsense mediated mRNA decay

Question 11

elongation mutations

Answer 11

is a point mutation that results in the elimination of the physiological termination codon

Question 12

the 2 kinds of a splicing mutation are?

Answer 12

~ destroy a functional splicing site

~ create a novel spicing site

Question 13

the 3 consequences of a splicing mutation are?

Answer 13

~when the mutation affects the consensus sequence leading to exon skipping - encoded protein will not have all the aa hat he skipped exon coded for, also could cause frameshift
~activation of a cryptic splice site in an intron - production of wild-type and mutant transcripts, more aa than necessary
~activation of a cryptic splice site in an exon - production of wild type and mutant transcripts, loss of some aa

Question 14

what are the regulatory sequences

Answer 14

~TATA box
~transcription-factor binding sites
~enhancers/silences

Question 15

mutations categorized by function have 4 sections

Answer 15

~loss of function–phenotypes are recessive / oncosupressor genes
~gain of function–dominant phenotypes/ oncogenes
~dominant negative mutations–gene product adversely affects the wild type gene- dominant phenotype
~lethal mutations

Question 16

Classification of mutations based on fitness

Answer 16

~deleterious
~beneficial
~neutral (polymorphisms)