exam 3 (mutations)

Question 1

what is a mutation

Answer 1

permanent alteration to a DNA sequence from its normal

Question 2

what is an example of a reversible alteration to DNA

Answer 2

cytosine methylation

Question 3

what is a point mutation

Answer 3

single base change

Question 4

what is a transition

Answer 4

pyrimidine-purine base pair is replaced with a pyrimidine-purine

Question 5

what is a transversion

Answer 5

pyrimidine-purine base pair is replaced with a purine-pyrimidine

Question 6

what are the 4 examples of transitions

Answer 6

A–> G
G –> A
C –> T
T –> C

Question 7

what are the transversions examples of the 4 bases

Answer 7

A –> T, C
C –> A, G
G –> C, T
T –> A, G

Question 8

what is a deletion

Answer 8

removal of 1+ base(s)

Question 9

what is an insertion

Answer 9

addition of 1+ base(s)

Question 10

what 3 types of mutations are caused from point mutations

Answer 10

synonymous
missense
nonsense

Question 11

what are synonymous substitutions

Answer 11

mutations that don’t change the amino acid sequence, function of protein is maintained, aka a silent mutation

Question 12

what is a missense mutation

Answer 12

mutations that change the amino acid sequence of a protein, can be conservative or non-conservative

Question 13

what is a conservative mutation

Answer 13

amino acid encoded has similar properties of the allele, maintaining protein function and regulation

Question 14

what is non-conservative mutation

Answer 14

amino acid encoded has different properties than the specified allele, altering function and regulation

Question 15

what is a nonsense mutation

Answer 15

mutation that inserts a premature stop codon into mRNA sequence, being non-functional protein to be rapidly degraded

Question 16

what is a frameshift mutation

Answer 16

insertions and deletions of bases (not in multiples of 3), altering the reading and resulting in a different translation

Question 17

trinucleotide repeat expansion

Answer 17

repeats of a codon for a given amino acid, often causing pathogenic diseases

Question 18

what mutation results in Huntington’s disease

Answer 18

expansion of CAG repeats, leading to formation of toxic protein aggregates (needs 40+ to for sure infect)

Question 19

what is the difference between mutations vs polymorphisms

Answer 19

mutation- change away from wild-type allele

polymorphism- allele that is at least somewhat common in a population

Question 20

how are mutations classified

Answer 20

according to their affect on the function of the gene

Question 21

what is amorph/null

Answer 21

mutation that causes complete loss of gene function, usually recessive to the wild-type copy of the gene

Question 22

what is hypomorph

Answer 22

mutation that causes partial loss of gene function

Question 23

what is hypermorph

Answer 23

mutation that causes an increase in normal function of the encoded protein

Question 24

what is antimorph

Answer 24

mutation that causes the gene product to act in opposition of its normality, aka dominant negative mutations

Question 25

what is neomorph

Answer 25

mutation that causes the gene product to obtain a new function

Question 26

what are structural variations

Answer 26

mutations involved in large-scale alterations in chromosome structure, that affect many genes

Question 27

what are chromsomal translocations

Answer 27

reciprocal fusion of pieces of chromosomes to on another, often results in cancer

Question 28

what is the philadelphia chromosome

Answer 28

reciprocal translocation between chromosomes 9 and 22 in chronic leukemia, resulting in uncontrolled cell division