Ch. 12 - Gene Mutation

Question 1

A _____ is a change in a DNA sequence that can cause varying effects.

Answer 1

Mutation

Question 2

The term ______ is increasingly being used to mean both polymorphism and mutation.

Answer 2

Variant

Question 3

A mutation that occurs during the DNA replication preceding meiosis is called a ______.

Answer 3

Germline mutation

Question 4

A mutation that occurs during the DNA replication preceding a mitotic cell division is called a _____.

Answer 4

Somatic mutation

Question 5

A _____ mutation will be present in some of the cells in an individual’s body but will be absent from other cells.

Answer 5

Somatic

Question 6

Sickle-cell disease is caused by a mutation in the _____ globin polypeptide chain.

Answer 6

Beta

Question 7

Mutations that prevent collagen from assembling properly result in _____ .

Answer 7

Ehlers-Danlos syndrome

Question 8

In sickle-cell anemia, _____ abnormally aggregates.

Answer 8

Hemoglobin

Question 9

Both thalassemia and sickle-cell anemia result from problems in _____ delivery.

Answer 9

Oxygen

Question 10

The protein _____ accounts for more than 60% of the protein in bone and cartilage.

Answer 10

Collagen

Question 11

In _____ , not enough hemoglobin is produced.

Answer 11

Thalassemia

Question 12

Spontaneous mutations occur most commonly as a result of _____.

Answer 12

Errors in DNA replication

Question 13

An agent that causes mutations to occur is called a _____.

Answer 13

Mutagen

Question 14

Mitochondrial genes have a higher spontaneous mutation rate than nuclear genes because _____.

Answer 14

Mitochondria cannot repair their DNA

Question 15

A region where mutations occur more often than usual is called a _____.

Answer 15

Hot spot

Question 16

A(n) ______ changes a single base in a DNA sequence.

Answer 16

Point mutation

Question 17

A(n) _____ is a mutation that replaces a purine with another purine or a pyrimidine with another pyrimidine.

Answer 17

Transition

Question 18

A(n) ______ mutation adds bases to a DNA sequence.

Answer 18

Insertion

Question 19

A(n) ______ replaces a codon specifying an amino acid with a stop codon.

Answer 19

Nonsense mutation

Question 20

A(n) _____ is a mutation that replaces a purine with a pyrimidine or vice versa.

Answer 20

Transversion

Question 21

A(n) _____ changes a codon for one amino acid into a codon for a different amino acid.

Answer 21

Missense mutation

Question 22

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.

Answer 22

Frameshift mutation

Question 23

A(n) _____ removes bases from a DNA sequence.

Answer 23

Deletion mutation

Question 24

A mutation that causes an exon to be skipped is a _____ mutation.

Answer 24

Splice site

Question 25

A mutation that changes the DNA sequence CCA to CCC, but does not change the amino acid encoded by the sequence, is a _____ mutation.

Answer 25

Transversion

Question 26

An insertion of two nucleotides into the coding sequence of a gene would result in a _____ mutation.

Answer 26

Frameshift

Question 27

A(n) _____ occurs when a gene is duplicated and the two copies of the gene are next to each other.

Answer 27

Tandem duplication

Question 28

DNA sequences that vary in number from one person to another are called _____.

Answer 28

Copy number variants

Question 29

Ultraviolet light damages DNA by causing the formation of _____.

Answer 29

Thymine dimers

Question 30

Fungi can repair damage to DNA caused by ultraviolet light in a process called _____.

Answer 30

Photoreactivation

Question 31

In base ______ , one to five nucleotides of a DNA strand are replaced.

Answer 31

Excision repair

Question 32

In _____ , up to 30 nucleotides of a DNA strand may be replaced.

Answer 32

Nucleotide excision repair

Question 33

Newly replicated DNA is "proofread" by enzymes during ______.

Answer 33

Mismatch repair

Question 34

______ does not correct DNA damage but allows replication and transcription to proceed.

Answer 34

Damage tolerance

Question 35

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 _____.

Answer 35

Somatic mutation

Question 36

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?

Answer 36

They may each cause a different disease.

Question 37

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 _____.

Answer 37

Transposon

Question 38

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?

Answer 38

Polymorphism, variant

Question 39

Select the examples of mutants.

Answer 39

A person with polydactyly (extra fingers or toes) A dog born with a missing eye A mouse that is born deaf

Question 40

A mutation that can be passed on to all the cells in a person's progeny is a _____ mutation.

Answer 40

Germline

Question 41

In sickle cell disease, a _____ that is normally in the beta globin polypeptide is replaced with a _____.

Answer 41

Glutamic acid; valine

Question 42

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 _____.

Answer 42

Allelic diseases

Question 43

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 _____.

Answer 43

A conditional mutation

Question 44

Exposure to radioactive substances in the Earth's crust is an example of _____.

Answer 44

Natural exposure to mutagens

Question 45

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.

Answer 45

H-I-J-4-L

Question 46

What is the mechanism through which a pseudogene can interfere with the expression of a functional gene?

Answer 46

A crossover between a functional gene and a pseudogene renders the functional gene nonfunctional.

Question 47

Which of the following are true statements about synonymous codons?

Answer 47

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.

Question 48

Which of the following is an example of a mutation?

Answer 48

An addition of 2 nucleotides to a gene involved in eye formation

Question 49

A mutation is ______.

Answer 49

A change in a DNA sequence

Question 50

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 _____.

Answer 50

Jewel inherited two recessive mutant alleles in the beta globin gene that cause thalassemia

Question 51

The mutation that causes sickle cell disease _____.

Answer 51

Occurs in the same gene that, when mutated at a different location, causes beta thalassemia

Question 52

A chemical or physical agent that causes mutations is called a _____.

Answer 52

Mutagen

Question 53

A codon for which of the amino acids listed below has the most synonymous codons?

Answer 53

Serine

Question 54

A mutation expressed only under certain conditions is _____.

Answer 54

Conditional

Question 55

A mutation is more likely to affect a differentiated cell than a stem cell due to _____.

Answer 55

Skewed distribution of parental versus newly replicated DNA

Question 56

_____ can usually repair DNA damage caused by ultraviolet light.

Answer 56

Photoreactivation

Question 57

The type of DNA repair that corrects errors due to oxidative damage by replacing one to five nucleotides is _____.

Answer 57

Base excision repair