LIFESCI 2G03 Term Test 1 Questions and
Answers Fall 2024 with complete Solution;
McMaster University
mutation - ANSWER-a change in the DNA sequence
germline mutation - ANSWER-heritable, occurs in germ-line
cells, and is passed on/present in all cells of the progeny
somatic mutation - ANSWER-non heritable, does not occur in
germ-line cells, is not passed onto progeny, is passed onto all
descendants of that cell
what regions of the DNA are affected by germline and somatic
mutations, respectively? - ANSWER-both types of mutations
may affect the protein coding regions or the non-coding regions
what is the effect of mutations in protein coding regions? -
ANSWER-affects the polypeptide sequence, and may impact
protein function
what is the effect of mutations in non-coding regions? -
ANSWER-in non-coding RNA: impacts gene expression
in introns: impacts polypeptide sequence
wildtype allele - ANSWER-the more abundant allele
,mutant allele - ANSWER-the more rare allele
loss of function mutation + the 2 types - ANSWER-reduces or
abolishes protein function.
1. null (amorphic): complete loss of protein function
2. hypomorphic: incomplete, reduced activity
gain of function mutation + the 3 types - ANSWER-increased
activity or new function; or expression in the wrong place/time
1. hypermorphic: more protein or increased activity
2. neomorphic: generates a new function
3.dominant negative/anti-morphic: prevents the normal protein
from performing its homeostatic function
are loss-of-function and gain-of-function mutations usually
dominant or recessive? - ANSWER--loss of function: can be
either
-gain of function: almost always dominant
Tp53 - ANSWER-transcription factor that acts as the gatekeeper
of cell cycle progression; stopping the cell cycle if there is DNA
damage; tumor suppressor
what is Tp53 supposed to do when there is damaged DNA? -
ANSWER-promote apoptosis genes, promote DNA repair
genes, and inhibit cell cycle genes
DBD + function - ANSWER-the DNA binding domain,
important for Tp53 to bind to DNA and regulate transcription
, What happens when there is a loss of function of DBD? -
ANSWER-reduction in DNA binding capacity, abolished gene
expression, increased proliferation of mutated cells
what type of mutation causes a mutant p53 protein? -
ANSWER-dominant negative/anti-morphic mutation
what happens when there is a mutant p53 protein? - ANSWER--
suppresses the function of wild type p53
-does the opposite of what's supposed to happen: inhibits
apoptosis genes, inhibits DNA repair genes, and promotes cell
cycle genes
spontaneous mutation - ANSWER-occurs randomly with no
known cause
induced mutation - ANSWER-arises due to exposure to
mutagenic agents and radiation
what happens more often, spontaneous or induced mutations? -
ANSWER-induced
point mutation + types - ANSWER-change in a single
nucleotide, or a few base pairs. types: substitution, deletion,
insertion
chromosomal rearrangement - ANSWER-large deletions,
insertions, inversions, or translocations. at the chromosomal
level, sometimes deletions and insertions happen together
aneuploidy - ANSWER-changes in chromosome number
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