Ch. 12 - Gene Mutation Flashcards
A _____ is a change in a DNA sequence that can cause varying effects.
Mutation
The term ______ is increasingly being used to mean both polymorphism and mutation.
Variant
A mutation that occurs during the DNA replication preceding meiosis is called a ______.
Germline mutation
A mutation that occurs during the DNA replication preceding a mitotic cell division is called a _____.
Somatic mutation
A _____ mutation will be present in some of the cells in an individual’s body but will be absent from other cells.
Somatic
Sickle-cell disease is caused by a mutation in the _____ globin polypeptide chain.
Beta
Mutations that prevent collagen from assembling properly result in _____ .
Ehlers-Danlos syndrome
In sickle-cell anemia, _____ abnormally aggregates.
Hemoglobin
Both thalassemia and sickle-cell anemia result from problems in _____ delivery.
Oxygen
The protein _____ accounts for more than 60% of the protein in bone and cartilage.
Collagen
In _____ , not enough hemoglobin is produced.
Thalassemia
Spontaneous mutations occur most commonly as a result of _____.
Errors in DNA replication
An agent that causes mutations to occur is called a _____.
Mutagen
Mitochondrial genes have a higher spontaneous mutation rate than nuclear genes because _____.
Mitochondria cannot repair their DNA
A region where mutations occur more often than usual is called a _____.
Hot spot
A(n) ______ changes a single base in a DNA sequence.
Point mutation
A(n) _____ is a mutation that replaces a purine with another purine or a pyrimidine with another pyrimidine.
Transition
A(n) ______ mutation adds bases to a DNA sequence.
Insertion
A(n) ______ replaces a codon specifying an amino acid with a stop codon.
Nonsense mutation
A(n) _____ is a mutation that replaces a purine with a pyrimidine or vice versa.
Transversion
A(n) _____ changes a codon for one amino acid into a codon for a different amino acid.
Missense mutation
A(n) _____ is an insertion or deletion of DNA bases from a coding sequence in which the number of bases added or removed is NOT a multiple of three.
Frameshift mutation
A(n) _____ removes bases from a DNA sequence.
Deletion mutation
A mutation that causes an exon to be skipped is a _____ mutation.
Splice site
A mutation that changes the DNA sequence CCA to CCC, but does not change the amino acid encoded by the sequence, is a _____ mutation.
Transversion
An insertion of two nucleotides into the coding sequence of a gene would result in a _____ mutation.
Frameshift
A(n) _____ occurs when a gene is duplicated and the two copies of the gene are next to each other.
Tandem duplication
DNA sequences that vary in number from one person to another are called _____.
Copy number variants
Ultraviolet light damages DNA by causing the formation of _____.
Thymine dimers
Fungi can repair damage to DNA caused by ultraviolet light in a process called _____.
Photoreactivation
In base ______ , one to five nucleotides of a DNA strand are replaced.
Excision repair
In _____ , up to 30 nucleotides of a DNA strand may be replaced.
Nucleotide excision repair
Newly replicated DNA is “proofread” by enzymes during ______.
Mismatch repair
______ does not correct DNA damage but allows replication and transcription to proceed.
Damage tolerance
A mutation that causes a patch of white hair on a person’s head when the rest of his hair is brown is most likely a _____.
Somatic mutation
You have performed exome sequencing and have identified a gene in which two different mutant forms are prevalent. Each mutation is a missense mutation, but they are found in different parts of the gene. What can you conclude about these mutations?
They may each cause a different disease.
When a gene is disrupted by a DNA sequence “jumping” into it and disrupting the reading frame, the DNA sequence that jumps into the gene is called a _____.
Transposon
In dogs, a gene that contributes to coat pigmentation and patterning has 5 different alleles that are commonly observed: E, Em, Eg, Eh and e. Which term(s) apply to these alleles?
Polymorphism, variant
Select the examples of mutants.
A person with polydactyly (extra fingers or toes)
A dog born with a missing eye
A mouse that is born deaf
A mutation that can be passed on to all the cells in a person’s progeny is a _____ mutation.
Germline
In sickle cell disease, a _____ that is normally in the beta globin polypeptide is replaced with a _____.
Glutamic acid; valine
A gene called SHANK3 encodes a protein that helps organize other proteins in neurons. Mutations in this gene have been linked to both autism and schizophrenia. This is an example of _____.
Allelic diseases
Siamese cats have distinctive coats, with black ears, face, and tail, and white fur covering the rest of their body. This coloring is the result of a defective enzyme that is involved in melanin synthesis. The produced enzyme is heat sensitive. It doesn’t function to produce pigment in the warmer parts of the mutant cats’ bodies but does produce pigment in cooler areas of the skin. This is an example of _____.
A conditional mutation
Exposure to radioactive substances in the Earth’s crust is an example of _____.
Natural exposure to mutagens
Consider the following gene:
Exon H - Intron 1 - Exon I - Intron 2 - Exon J - Intron 3 - Exon K - Intron 4 - Exon L.
The gene undergoes 2 splice-site mutations, one causes Intron 4 to be retained, and another that causes skipping of Exon K. Select the correct structure of the translated protein.
H-I-J-4-L
What is the mechanism through which a pseudogene can interfere with the expression of a functional gene?
A crossover between a functional gene and a pseudogene renders the functional gene nonfunctional.
Which of the following are true statements about synonymous codons?
Synonymous codons encode the same amino acids.
Mutation to a synonymous codon can affect mRNA splicing.
Mutation to a synonymous codon can affect mRNA stability.
Which of the following is an example of a mutation?
An addition of 2 nucleotides to a gene involved in eye formation
A mutation is ______.
A change in a DNA sequence
Sanjay and Indira have thalassemia minor. Their young daughters are dizygotic (fraternal) twins. Malonie has thalassemia minor like her parents, but Jewel has the more severe thalassemia major. The more serious case most likely arose because _____.
Jewel inherited two recessive mutant alleles in the beta globin gene that cause thalassemia
The mutation that causes sickle cell disease _____.
Occurs in the same gene that, when mutated at a different location, causes beta thalassemia
A chemical or physical agent that causes mutations is called a _____.
Mutagen
A codon for which of the amino acids listed below has the most synonymous codons?
Serine
A mutation expressed only under certain conditions is _____.
Conditional
A mutation is more likely to affect a differentiated cell than a stem cell due to _____.
Skewed distribution of parental versus newly replicated DNA
_____ can usually repair DNA damage caused by ultraviolet light.
Photoreactivation
The type of DNA repair that corrects errors due to oxidative damage by replacing one to five nucleotides is _____.
Base excision repair
