Chapter 14: Gene Mutation, Repair, and Transposition Flashcards
True or False. A mutation can be defined as an alteration in DNA sequence. Any base-pair change in any part of a DNA molecule can be considered a mutation.
True
True or False. Mutations that occur in somatic cells are heritable and are the basis for the transmission of genetic diversity and evolution, as well as genetic diseases.
False. Germ cells
The type of mutation that involves a change of one base pair to another in a DNA molecule.
Point mutation or Base substitution
A change of one nucleotide of a triplet within a protein-coding portion of a gene may result in the creation of a new triplet that codes for a different amino acid in the protein product. This type of mutation is called?
Missense mutation
A change of one nucleotide of a triplet within a protein-coding portion of a gene may result in the creation of a stop codon. This mutation is called?
Nonsense mutation
If the point mutation alters a codon but does not result in a change in the amino acid at that position in the protein (due to degeneracy of the genetic code), this mutation is called?
Silent mutation
In a base substitution mutation, a pyrimidine replaces a pyrimidine or a purine replaces a purine. This mutation is referred to as?
Transition mutation
In a base substitution mutation, a purine replaces a pyrimidine or vice versa. This mutation is referred to as?
Transversion mutation
A mutation, either an insertion or deletion of nucleotides, that alters the triplet reading frame is called?
Frameshift mutation
True or False. A frameshift mutation will occur when any number of bases are added or deleted, except multiples of three, which would reestablish the initial frame of reading.
True
A type of mutation that reduces or eliminates the function of the gene product.
Loss-of-function mutation
Mutations that result in complete loss of function are known as?
Null mutations
True or False. Most loss-of-function mutations are dominant.
False. Recessive
Results in a wild-type phenotype when present in a diploid organism and the other allele is wild type.
Recessive mutation
Results in a mutant phenotype in a diploid organism, even when the wild-type allele is also present.
Dominant mutation
Occurs when the single wild-type copy of the gene does not produce enough gene product to bring about a wild-type phenotype.
Haploinssufficiency
This disease in humans is an example of a disorder caused by haploinsufficiency—in this case as a result of a loss-of-function mutation in one copy of the FBN1 gene.
Marfan syndrome
This mutation results in a gene product with enhanced, negative, or new functions.
Dominant gain-of-function mutation
Causes of dominant gain-of-function mutation.
- Change in the amino acid sequence of the protein that confers a new activity
- A mutation in a regulatory region of the gene, leading to expression of the gene at higher levels or at abnormal times or places.
This type of mutation may directly interfere with the function of the product of the wild-type allele. Often this occurs when the mutant nonfunctional gene product binds to the wild-type gene product, inactivating it.
Dominant negative mutation
These mutations are recognized by their ability to alter a normal or wild-type visible phenotype.
Visible mutation
This mutation results in a loss of ability to synthesize an amino acid or vitamin.
Nutritional mutation
Although these kinds of mutations do not always affect morphological characters, they affect the function of proteins that can impinge on the well-being and survival of the affected individual.
Biochemical mutation
This category of mutations consists of mutations that affect the behavior patterns of an organism.
Behavioral mutations
This kind of mutation disrupts a regulatory gene or a gene control region which results in the disruption of the normal regulatory processes and inappropriate activation or inactivation of a gene.
Regulator mutations
This kind of mutation adversely affects a gene product that is essential to the survival of the organism.
Lethal mutation
These mutations are present in the genome of an organism but can be detected only under certain conditions.
Conditional mutations
This is a type of conditional mutation whereby at a “permissive” temperature, the mutant gene product
functions normally, but it loses its function at a different, “restrictive” temperature.
Temperature-senstive mutations
A mutation that can occur either in a protein-coding region or in any part of the genome, and its effect on the genetic fitness of the organism is negligible.
Neutral mutation
Mutations that are occurring in any cell in the body except germ cells.
Somatic mutations
Are mutations within genes located on the autosomes.
Autosomal mutations
Are mutations within genes located on the X chromosome.
X-linked mutation
Are mutations within genes located on the Y chromosome.
Y-linked mutation
True or False. Somatic mutations will have a greater impact if they are dominant or, in males, if they are X-linked since such mutations are most likely to be immediately expressed.
True
Are mutations in the nucleotide sequence of genes that appear to occur naturally.
Spontaneous mutation
Are mutations that result from the influence of extraneous factors.
Induced mutations
Defined as the likelihood that a gene will undergo a mutation in a single generation or in forming a single gamete.
Mutation rate
Some DNA sequences appear to be highly susceptible to mutation and are known as?
Mutation Hotspot
Are alternate chemical forms that differ by only a single proton shift in the molecule.
Tautomers
