MUTATIONs Flashcards
(12 cards)
•Changes to nucleic acid sequence (DNA and RNA)
•Mutations in DNA can be inherited (_________________)
or not inherited (________________)
•Changes can be small (____ ____) or large (_________)
•Altered gene sequence can change the amino acid
sequence of the polypeptide resulting in variation of
_______.
•Effect on ________ can be harmless/neutral,
harmful /deleterious or beneficial/advantageous.
•_______ _____ in evolution where nature selection favors
________ mutation
•Changes to nucleic acid sequence (DNA and RNA)
•Mutations in DNA can be inherited (______germline )
or not inherited (__somatic)
•Changes can be small (gene level) or large (chromosomal)
•Altered gene sequence can change the amino acid
sequence of the polypeptide resulting in variation of
phenotype.
•Effect on phenotype can be harmless/neutral,
harmful /deleterious or beneficial/advantageous.
•Primary force in evolution where nature selection favors
beneficial mutation
_______ ______: can occur in all other cell types except _______ and therefore NOT INHERITABLE
•Mutation occurs in a ________ cell and all other ________ cells will express the mutation
•Somatic mutations are expressed as _____
(size depends on when the mutation occurured in ___________
•_____ ______ are an example of somatic mutations
Somatic mutations : can occur in all other cell types except gametes and therefore NOT INHERITABLE
•Mutation occurs in a progenitor cell and all other daughter cells will express the mutation
•Somatic mutations are expressed as sectors
(size depends on when the mutation occurred in development
•Cancer tumors are an example of somatic mutations
Small-scale mutations: changes to one or few ____ _____
(Changes to ____ sequence)
Original
•Base substitution: single _______ change
•Insertion: one or more base pairs ________ in sequence during
____ _________ . Can result in a _________ mutation.
•Deletion: one or more base pairs ______ during DNA
replication. Can result in a ________ mutation.
QUESTION: Can these types of mutations occur in introns?
In exons? *CHECK
In telomeres?
In centromeres?
Small-scale mutations: changes to one or few base pairs
(Changes to DNA sequence)
Original
•Base substitution: single nucleotide change
•Insertion: one or more base pairs added in sequence during
DNA replication. Can result in a frameshift mutation.
•Deletion: one or more base pairs skipped during DNA
replication. Can result in a frameshift mutation.
QUESTION: Can these types of mutations occur in introns? Yes?
In exons?Yes?
In telomeres?
In centromeres?
Spontaneous:
• _______ _______ mutations mainly caused by DNA replication errors (1
mutation/1010 bp of DNA replicated)
• Spontaneous chemical alterations to bases occur naturally in cells, but are usually
_________ by ___ ______ mechanisms
Induced:
•
____________________ (can be either natural
or artificial): Agent that causes mutations at a
rate much _______ than spontaneous mutagens
• Mutagens induce mutations by ________ a
Base,________ a base so that it mis-pairs with
another base, or ________ a base so that it
can no longer pair correctly.
UV-> distortions to DNA _______
Cigarets? - damage to dna _____
Spontaneous:
• Naturally-occurring mutations mainly caused by DNA replication errors (1
mutation/1010 bp of DNA replicated)
• Spontaneous chemical alterations to bases occur naturally in cells, but are usually
repaired by DNA repair mechanisms
Induced:
•
___MUTAGENS (can be either natural
or artificial): Agent that causes mutations at a
rate much higher than spontaneous mutagens
• Mutagens induce mutations by replacing a
base, altering a base so that it mis-pairs with
another base, or damaging a base so that it
can no longer pair correctly.
UV-> distortions to DNA structure
Cigarets? - damage to dna bases
Effect of mutations on the amino acid
sequence of polypeptides
If the mutation occurs in the
__________________________,
there may be impacts on the encoded polypeptide.
•
___________________ mutation (nonsynonymous): codon change causes
change in an amino acid
•
___________________ mutation (premature stop): sense codon change into
a stop codon (truncated polypeptide)
•
___________________(synonymous): codon change does not change the
amino acid due to degeneracy of the genetic code
•
_________ mutation: insertion or deletion of a small number of
base pairs that alter the reading frame
(trick?) QUESTION: which type(s) of mutation would have the most effect on
the function of the polypeptide?
Effect of mutations on the amino acid
sequence of polypeptides
If the mutation occurs in the
_______exon of a gene ,
there may be impacts on the encoded polypeptide.
•
__missense_ mutation (nonsynonymous): codon change causes
change in an amino acid
•
___nonsense_ mutation (premature stop): sense codon change into
a stop codon (truncated polypeptide)
•
___silent _(synonymous): codon change does not change the
amino acid due to degeneracy of the genetic code
•frameshift mutation: insertion or deletion of a small number of
base pairs that alter the reading frame
(trick?) QUESTION: which type(s) of mutation would have the most effect on
the function of the polypeptide?
DEPENDS ON THE LOCATION
LARGE SCALE CHROMOSOMAL MUTATIONS:
•_________: loss of genes
•Duplication/amplification: increasing _______ of genes, more _______
•Translocation: _________ of genetic parts from___________ chromosomes
•Inversion: ________ ______ of a segment of the chromosome
•Deletion: loss of genes
•Duplication/amplification: increasing dosage of genes, more protein
•Translocation: interchange of genetic parts from nonhomologous chromosomes
•Inversion: reversing orientation of a segment of the chromosome
Phenotypes of various mutant alleles
Allele: one of different forms of a gene (sequence variation) which can cause
different ____________
•Wild-type allele: form of the gene most found in ______ or the
standard laboratory _____ of a model organism
Wild-type zebra fish
•Loss-of-function (LOF) alleles: mutations that _____/_______
gene _______/________
Loss-of-function mutation in pigment gene
•Gain-of-function (GOF) alleles: mutations that enhance gene
function /expression
Why we do genetic research in ___________________________
(E. coli, yeast, Drosophila, corn, zebra fish, mouse, etc)?
Phenotypes of various mutant alleles
Allele: one of different forms of a gene (sequence variation) which can cause
different phenotypes
•Wild-type allele: form of the gene most found in nature or the
standard laboratory strain of a model organism
Wild-type zebra fish
•Loss-of-function (LOF) alleles: mutations that reduce/eliminate
gene function/expression
Loss-of-function mutation in pigment gene
•Gain-of-function (GOF) alleles: mutations that enhance gene
function /expression
Why we do genetic research in ____model organism systems ______
(E. coli, yeast, Drosophila, corn, zebra fish, mouse, etc)?
The eukaryotic cell cycle
The cell cycle is an _______ set of processes
by which one cell grows and divides into two________ cells
Need to fully _______ DNA and organelles and properly
________ them to daughter cells
•
_______________________
: synthesis of proteins, RNA,
metabolites, other than DNA
•
_________________
: DNA replication
• M phase (______): _______ division
• _________: cell division
• G0: ______ phase or quiescence
Most adult human cells are in G0 either __________ (muscle or
nerve cells) or ____ ________ (liver cells reenter G1 during ______
The eukaryotic cell cycle
The cell cycle is an ordered set of processes
by which one cell grows and divides into two
daughter cells
Need to fully replicate DNA and organelles and properly
segregate them to daughter cells
•
__G1 and G2 (gap)
: synthesis of proteins, RNA,
metabolites, other than DNA
•
___S phase
: DNA replication
• M phase (mitosis): nuclear division
• Cytokinesis: cell division
• G0: resting phase or quiescence
Most adult human cells are in G0 either permanently (muscle or
nerve cells) or semi permanently (liver cells reenter G1 during injury
N: ________ number of chromosomes (eukaryotes)
2n(_______): diploid number of chromosomes (prokaryotes)
• _________ chromosomes: maternal and paternal pair of
chromosomes
The same number and order of genes but
________________ could be different
• Sister chromatids: _____________ copies of a chromosome.
Created during DNA replication. Joined at the centromere.
N: haploid number of chromosomes
2n(zygote): diploid number of chromosomes
• Homologous chromosomes: maternal and paternal pair of
chromosomes
The same number and order of genes but
____alleles could be different
• Sister chromatids: _identical copies of a chromosome.
Created during DNA replication. Joined at the centromere.
MITOSIS
1)G1 (2n) -> (4 chromosomes) (1 chromatid/chromosome) -> (S phase DNA replication• Chromosomes are not
visible• Centriole duplication
2)
3)
