UNIT 6 - GENETIC MUTATIONS Flashcards by Miguel O.

Gene Mutation or Chromosomal Mutation

A single gene is affected

Gene Mutation

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Gene Mutation or Chromosomal Mutation

Several genes are affected

Chromosomal Mutation

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Gene Mutation or Chromosomal Mutation

Alteration of the nucleotide sequence

Gene Mutation

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Gene Mutation or Chromosomal Mutation

Alterations in the chromosome structure or number

Chromosomal Mutation

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Gene Mutation or Chromosomal Mutation

Caused by errors in DNA ____ and mutagens

Gene Mutation

Replication

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Gene Mutation or Chromosomal Mutation

Caused by errors in crossing over during meiosis

Chromosomal Mutation

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A gene variant present in more than one percent of a population

Polymorphism

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True or False

A mutation is not always a change from wild type

True

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Which of the following statements is true about mutations?

A. They can produce new alleles of existing genes.
B. They can be inherited if they are in somatic cells.
C. They are never as simple as an error in a single codon in a DNA molecule.
D. A and B

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True or False

Genetic Polymorphism is not associated with any disease

True

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Variants in other
genes that counteract the loss of function

Made to silence or kill the expression of a specific gene

Knockouts

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A ____ is any heritable change in the amount or structure of genetic material

Mutation

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True or False

Natural selection does affects the alleles that bring polymorphism

False

Natural selection does not affect the alleles that bring polymorphism

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Polymorphism or Mutation

A permanent alteration of a nucleotide sequence of a gene

Mutation

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True or False

In polymorphism, a single base pair exchange is called a point mutation

False

Mutation, not polymorphism

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True or False

In polymorphism, a single base pair exchange in the nucleotide sequence is called a ____ ____ ____

Single Nucleotide Polymorphism

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Classification of mutations can be based on all, except:

A. Origin
B. Cell Type
C. Expression
D. Effect on Function
E. Molecular Change
F. None of the above

F. None of the above

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True or False

There is a direct relationship between the mutation rate and the size of a genome

False

Inverse relationship

The larger the genome, the smaller the mutation rate

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True or False

A large population of certain species means there will be high mutation rates

False

Mutation rates are inversely proportional to population sizes of species

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The ____ of DNA polymerase involves its ability to correct changes in the DNA and the accuracy with which the DNA sequence is copied

Fidelity

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Based on Origin

Occurs in the absence of a known mutagen

Mutations based on origin

Spontaneous

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Based on Origin

Occurs in the presence of a known mutagen

Mutations based on origin

Induced

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Spontaneous mutations are similar to (endogenous, exogenous) mutations

Mutations based on origin

Endogenous

Having an internal cause or origin

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E____ refers to the random accumulation of deleterious mutations

Mutations based on origin

Entropy

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This mutagen causes congenital malformations; affects pluripotent stem cells ## Footnote Mutations based on origin

Teratogens

This mutagen causes tumor formation; involves cancer-causing agents ## Footnote Mutations based on origin

Carcinogens

This mutagen causes chromosomal abnormalities or breaks in chromosomes that result in the gain, loss, or rearrangements of chromosomal segments ## Footnote Mutations based on origin

Clastogens

This mutagen causes DNA damage ## Footnote Mutations based on origin

Non-specific

# Physical, Chemical, or Biological Mutagens? Ionizing radiations, Non-ionizing radiations, Heat ## Footnote Mutations based on origin

Physical mutagens

# Physical, Chemical, or Biological Mutagens? Alkylating agents, Deaminating agents, Intercalating agents ## Footnote Mutations based on origin

Chemical mutagens

# Physical, Chemical, or Biological Mutagens? Biological agents, Biological infectious agents ## Footnote Mutations based on origin

Biological mutagens

Viruses, Bacteria, and Transponons are under what class of mutagens? ## Footnote Mutations based on origin

Biological mutagens

Natural elements of DNA that jump from one place to another within a genome ## Footnote Also called "jumping genes"

Transponons

# Exogenous or Endogenous UV-Light ## Footnote Mutations based on origin

Exogenous

# Exogenous or Endogenous Smoking ## Footnote Mutations based on origin

Exogenous

# Exogenous or Endogenous Spontaneous or enzymating DNA base modifications ## Footnote Mutations based on origin

Endogenous

# Exogenous or Endogenous DNA replication errors ## Footnote Mutations based on origin

Endogenous

# True or False Reactive oxygen species are both exogenous and endogenous sources of mutation ## Footnote Mutations based on origin

True

Dipyrimidine photoproducts (CPD, 6-4PP) are caused by ## Footnote Mutations based on origin

UV-light

Bulky DNA adducts at guanines (BPDE-dG) are caused by ## Footnote Mutations based on origin

Smoking

A pair of abnormally chemically bonded adjacent thymine Bases in DNA, resulting from damage by ultra-violet irradiation ## Footnote Mutations based on origin

Thymine dimers

DNA repair enzymes that repair damage caused by exposure to ultraviolet light ## Footnote Mutations based on origin

Photolyases | Not present in humans

A rapid, transient, production of huge amounts of reactive oxygen species; acts as a defence mechanism to pathogen infection in plants ## Footnote Mutations based on origin

Oxidative burst

Mechanisms of repair for DNA replication errors ## Footnote Mutations based on origin

Nucleotide excision repair Base incision repair Mismatch repair

Three Types of Chemical Mutagens ## Footnote Mutations based on origin

Base analogs Base altering agents Intercalating agents

Types of base altering agents in chemical mutagens ## Footnote Mutations based on origin

Deaminating agents Hydroxylating agents Alkylating agents

Type of mutation that occurs in nonreproductive cells ## Footnote Mutations based on cell type

Somatic

# Mutations can be caused by all of the following except: A. radiation B. some chemicals C. incest D. some microorganisms E. none of the above ## Footnote Mutations based on origin

C. incest | Incest does not increase the likelihood of mutations occurring

In order for a mutation to be selected for or against by natural selection, it must: A. be a gross chromosomal rearrangement or an irregular number of chromosomes B. occur in the genotype C. be expressed in the phenotype

C. be expressed in the phenotype

# The following are true for somatic mutation, except: A. Happens during DNA replication before mitosis B. Passed to the next generation of cells C. Passed to all the cells in the individual’s body D. All the cells that descend from the original changed cell are altered, but they might only comprise a small part of the body ## Footnote Mutations based on cell type

C | Somatic mutations are not passed to all cells in the body

# True or False A person with somatic mutations will have mosaicism ## Footnote Mutations based on cell type

True

# True or False Most expression of germline mutations is in the form of cancer ## Footnote Mutations based on cell type

False | Somatic mutations, not germline

In this mutation, only one area/organ of the body is usually affected ## Footnote Mutations based on cell type

Somatic mutation

This type of mutation occurs in reproductive cells and can be inherited ## Footnote Mutations based on cell type

Germline mutations

# True or False In germline mutations, the resulting gamete and all the cells that descend from it after fertilization have the mutation—that is, every cell in the body ## Footnote Mutations based on cell type

True

Which germ cell is more commonly related to de novo mutations? ## Footnote Mutations based on cell type

Sperm cells

# True or False Egg cells are associated with aneuploidy rather than mutations ## Footnote Mutations based on cell type

True

A mutation that is expressed only under restrictive conditions | Expressed only under certain conditions ## Footnote Mutations based on expression

Conditional

In unconditional mutations, the effect of mutation can be turned on or off by the experimenter ## Footnote Mutations based on expression

False | Unconditional mutations are expressed all of the time; Conditional dapat

A mutation that is expressed under permissive conditions as well as restrictive conditions ## Footnote Mutations based on expression

Unconditional

Example of unconditional mutations ## Footnote Mutations based on expression

Hemophilia Sickle cells

Loss of function mutations are also called A____ ## Footnote Mutations based on effect on function

Amorphic

This type of mutation results in complete gene inactivation or in a completely nonfunctional gene product; eliminates normal function ## Footnote Mutations based on effect on function

Loss of function/Amorphic

This type of mutation reduces normal function, but does not eliminate the level of expression of a gene or the activity of the gene product ## Footnote Mutations based on effect on function

Hypomorphic (Leaky mutation)

# True or False Leaky mutations show up in both restrictive and permissive conditions ## Footnote Mutations based on effect on function

False | Restrictive only

This type of mutation increases normal function and produces a greater-than-normal level of gene expression ## Footnote Mutations based on effect on function

Hypermorphic

This type of mutation changes the regulation of the gene so that the gene product is overproduced ## Footnote Mutations based on effect on function

Hypermorphic

Neomorph mutation is also called ____ expression ## Footnote Mutations based on effect on function

Ectopic

This type of mutation results in a new function -- expressed at an incorrect time or in an inappropriate cell ## Footnote Mutations based on effect on function

Neomorph

# True or False Neomorphic mutations quantitatively alters the action of a gene ## Footnote Mutations based on effect on function

False | Qualitative, not quantitative

This type of mutation causes a gene to become active in a type of cell or tissue in which the gene is not normally active ## Footnote Mutations based on effect on function

Neomorph

This type of mutation involves a mutant gene product which interferes with normal gene product ## Footnote Mutations based on effect on function

Antimorphic

# Gain or loss of function? Antimorphic mutations ## Footnote Mutations based on effect on function

Loss of function

# Gain or loss of function? Neomorphic mutations ## Footnote Mutations based on effect on function

Gain of function

# Gain or loss of function? Hypermorphic mutations ## Footnote Mutations based on effect on function

Gain of function

# Gain or loss of function? Hypomorphic/Leaky mutations ## Footnote Mutations based on effect on function

Loss of function

Recessive mutations are usually a ____ of function ## Footnote Mutations based on effect on function

Loss

What are the types of mutations based on molecular change? ## Footnote Mutations based on molecular change

Substitutions Deletions Insertions Duplications Inversions Translocations

This type of mutation involves the replacement of a single nucleotide by another ## Footnote Mutations based on molecular change

Substitutions

# Transition or Transversion Replacement by the same type of nucleotide ## Footnote Mutations based on molecular change

Transition

# Transition or Transversion Pyrimidine to Purine Purine to Pyrimidine ## Footnote Mutations based on molecular change

Transversion

Which transition is more frequent? Pyrimidine to Pyrimidine or Purine to Purine? ## Footnote Mutations based on molecular change

Pyrimidine to Pyrimidine | Due to CpG dinucleotides

Short stretches of DNA with an unusually high GC content and a higher frequency of CpG dinucleotides ## Footnote Mutations based on molecular change

CpG islands

Which is worse? Transitions or Transversions? ## Footnote Mutations based on molecular change

Transversions

# True or False There is one possibility in transversions ## Footnote Mutations based on molecular change

False | There are two possible transversions

What charactersitic of the genetic code saves the amino acid sequence from transitions? ## Footnote Mutations based on molecular change

Degeneracy or Wobble

This type of mutation involves the loss of one or more nucleotides ## Footnote Mutations based on molecular change

Deletions

Patterns of deletion ## Footnote Mutations based on molecular change

Multiple of 3 nucleotides (codon) Not multiple of 3 Large deletion

This type of deletion pattern arises through unequal crossover between repeat sequences ## Footnote Mutations based on molecular change

Large deletion

# True or False Large deletion results in improper pairing during meiosis ## Footnote Mutations based on molecular change

True

Which likely results in a frameshift mutation? Indels with a multiple of 3 or not a multiple of 3 ## Footnote Mutations based on molecular change

Not a multiple of 3

# Classical or Molecular Genetics **Point mutations** are refered to as any mutation small enough to be unobservable under a light microscope ## Footnote Mutations based on molecular change

Classical Genetics

# Classical or Molecular Genetics **Point mutations** are refered to as a single base-pair mutations ## Footnote Mutations based on molecular change

Molecular Genetics

A one-base change in the sequence of one side that merits a change on the base of the complementary sequence ## Footnote Mutations based on molecular change

Point mutation

Cystic fibrosis is an example of what type of mutation? ## Footnote Mutations based on molecular change

Three-base deletion

What amino acid is missing in cystic fibrosis? ## Footnote Mutations based on molecular change

amino acid 508 (phenylalanine)

What is the role of phenylalanine in protein synthesis? ## Footnote Mutations based on molecular change

Contributes to the structural framework and functionality of proteins by **forming peptide bonds during translation**

This type of mutation involves the addition of one or more nucleotides into a gene ## Footnote Mutations based on molecular change

Insertion

Amplification of a sequence of three nucleotides, which prevents normal expression of the gene ## Footnote Mutations based on molecular change

Trinucleotide Repeat Expansion (TNR)

What disease is caused by expansion of trinucleotide repeats? ## Footnote Mutations based on molecular change

Huntington's Disease

# True or False Trinucleotide Repeat Expansions do not actually code for proteins, they just prolong the portion of the gene ## Footnote Mutations based on molecular change

True

Trinucleotide Repeat Expansion disorder involving **CGG repeats** ## Footnote Mutations based on molecular change

Fragile X Syndrome

Trinucleotide Repeat Expansion disorder involving **CAG repeats** ## Footnote Mutations based on molecular change

Huntington Disease

Trinucleotide Repeat Expansion disorder involving **CTG repeats** ## Footnote Mutations based on molecular change

Myotonic dystrophy

Trinucleotide Repeat Expansion disorder involving **GAA repeats** ## Footnote Mutations based on molecular change

Friedreich ataxia

What gene is affected in **Fragile X syndrome**? ## Footnote Mutations based on molecular change

FMR1 gene

What gene is affected in **Huntington's Disease**? ## Footnote Mutations based on molecular change

HTT gene

What gene is affected in **Myotonic dystrophy**? ## Footnote Mutations based on molecular change

DMPK gene

What gene is affected in **Friedreich ataxia**? ## Footnote Mutations based on molecular change

FXN1 gene

# Fragile X Syndrome Mutation 30 CGG permutations ## Footnote Mutations based on molecular change

Wild-type allele

# Fragile X Syndrome Mutation 50-200 CGG permutations ## Footnote Mutations based on molecular change

Premutation

# Fragile X Syndrome Mutation >230 CGG permutations ## Footnote Mutations based on molecular change

Mutant allele

# Synonymous or Nonsynonymous Mutations Silent mutations are classified as ## Footnote Mutations based on their effect on protein products

Synonymous Mutations

Types of Nonsynonymous Mutations ## Footnote Mutations based on their effect on protein products

Missense mutations Nonsense mutations Frameshift mutations

# True or False Synonymous mutations do not alter the polypeptide product of the gene ## Footnote Mutations based on their effect on protein products

True | No effect on the protein sequence

This nonsynonymous mutation involves base-pair substitutions that produce a change in a single amino acid ## Footnote Mutations based on their effect on protein products

Missense mutations

# Missense, Nonsense, or Frameshift? Nonpolar amino acid is replaced with a polar amino acid ## Footnote Mutations based on their effect on protein products

Missense

A type of missense mutation that results in the substitution of similar but not identical amino acids | Same functional group ## Footnote Mutations based on their effect on protein products

Conservative Missense Mutation

A type of missense mutation where the alteration in nucleotide causes the formation of a completely different kind of amino acid in the chain ## Footnote Mutations based on their effect on protein products

Non-conservative Missense Mutation

# True or False Sickle cell anemia is an example of a missense mutation ## Footnote Mutations based on their effect on protein products

True

What position and chain is the change of amino acids in sickle cell anemia? ## Footnote Mutations based on their effect on protein products

Position 6, Beta chain

Amino acid ____ ____ is replaced with ____ in sickle cell anemia ## Footnote Mutations based on their effect on protein products

Glutamic acid, Valine

What is the abnormal hemoglobin product of the single nucleotide substitution in sickle cell anemia? ## Footnote Mutations based on their effect on protein products

Hemoglobin S (HbS)

A type of nonsynonymous mutation that involves base-pair substitutions that produce a **stop codon** in the mRNA ## Footnote Mutations based on their effect on protein products

Nonsense Mutations

This type of mutation results in a premature termination of the polypeptide chain ## Footnote Mutations based on their effect on protein products

Nonsense Mutations

**Beta-0 thalassemia** is an example of what type of nonsynonymous mutation? ## Footnote Mutations based on their effect on protein products

Nonsense Mutations

# True or False Beta-0 thalassemia is a heterozygous phenomenon ## Footnote Mutations based on their effect on protein products

False | Homozygous

What amino acid is affected in Beta-0 thalassemia? What is substituted? ## Footnote Mutations based on their effect on protein products

Glutamine (CAG), U is substituted for C (UAG)

# Transition or Transversion Beta-0 thalassemia

Transition

Frameshift mutations are also called i____

indels

A mutation that involves the insertion or deletion of nucleotides that are not a multiple of three, where the reading frame is altered

Frameshift mutation

Tay-Sachs disease is what type of mutation?

Frameshift mutation | Four base insertion in the **hexosaminidase A gene**

# True or False In frameshift mutations, the resulting amino acid sequence bears **no resemblance** to the normal sequence

True

The O allele is a result of what type of mutation?

Frameshift mutation | Single-base deletion at the **ABO (glycosyltransferase) locus**

A genetic mutation that inserts, deletes or changes a number of nucleotides in the specific site at which splicing takes place during the processing of precursor messenger RNA into mature messenger RNA

Splice site mutation

# Partial or Whole gene duplication or insertion May result in premature termination with loss of function or expression

Partial gene duplication or insertion

Type of mutation that involves aberrant splicing--exon skipping or intron retention

Splice site mutation

DNA point mutations _____. A. Have no effect because of the redundancy of the nucleotide code. B. Causes an incorrect amino acid, but no change in the overall protein. C. Always leads to a nonfunctional protein. D. Can lead to a nonfunctional protein or can have little effect depending on the position of the mutation. E. Lead to the formation of an alternative protein structure, but the function of the protein doesn't change.

UNIT 6 - GENETIC MUTATIONS Flashcards

(138 cards)