Module 4
In a(n) _______, part of a chromosome is present twice.
duplication
A(n) ________________ changes a codon for one amino acid into a codon for a different amino acid.
missense mutation
In a(n) ____________, parts of two chromosomes have been exchanged
translocation
A(n) ______________ is a mutation that replaces a purine with a pyrimidine or vice versa.
transversion
The term _________ is increasingly being used to mean both polymorphism and mutation.
variant
Why are nonsense mutations rare?
Because their effect on survival is great.
Which characteristic of the genetic code lowers the likelihood of a mutation resulting in a change of a protein function? a. Its universality. b. Its non-overlapping nature. c. Its redundancy. d. All of the above.
C
Which of the following cannot be caused by a mutation? a. Loss of a protein function. b. Lowering the amount of protein produced. c. Gain of a new/different protein function. d. All of the above can be caused by a mutation.
D
Which of the following is least likely to cause a mutation? a. Ionizing radiation. b. UV radiation. c. Estrogen. d. Liquified cigarette smoke. e. Vinegar. f. All of the above are known to be pontent mutagens.
E
Exposure to which chemicals or foods increases cancer risk? Check all that apply.
Insecticides Herbicides Fungicides Fumigants Cooked red meat
Which of the following characteristics are typical of cancer cells?
Loss of cell cycle controlLoss of cell cycle control Dedifferentiated Lack contact inhibition Can induce blood vessel formation
The type of chromosome abnormality that yields a long chromosome consisting of most of two acrocentric chromosomes is a(n)
Robertsonian translocation.
Which of the following statements is true about mutations?
They can produce new alleles of existing genes.
Match syndromes to their corresponding karyotypes
Turner: 45, XO Klinefelter: 47, XXY Jackobs: 47, XYY
Cancer can result from a failure of
a cell cycle checkpoint
A cell with a single extra chromosome or missing chromosome is
aneuploid.
Spindle fibers (microtubules) attach to a chromosome's _____ during mitosis.
centromere
In a(n) ________ , part of a chromosome is missing.
deletion
A(n) _________________ removes bases from a DNA sequence.
deletion mutation
Spontaneous mutations occur most commonly as a result of
errors in DNA replication
A cell with a normal chromosome number is
euploid
The cause of p53-related cancers is
failure to repair damaged DNA, allowing the cell to continue dividing.
All tumors are cancerous
false
Cancer begins when a cell divides less frequently than it should.
false
Most cases of cancer arise from inheriting a cancer susceptibility allele from a parent.
false
Oncogenes cause cancer when they are inactivated.
false
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
Cancer susceptibility is passed onto future generations when a(n) ________ mutation has occurred.
germline
A mutation that occurs during the DNA replication preceding meiosis is called a
germline mutation
A region where mutations occur more often than usual is called a
hot spot
A(n) ________________ adds bases to a DNA sequence.
insertion mutation
In a(n) ________, the order of a segment of a chromosome is reversed.
inversion
A(n) ________________ is a chromosome with two identical arms.
isochromosome
Mitochondrial genes have a higher spontaneous mutation rate than nuclear genes because
mitochondria cannot repair their DNA
In _________, one chromosome is missing.
monosomy
An agent that causes mutations to occur is called a
mutagen
A ________ is a change in a DNA sequence that is rare and typically affects the phenotype.
mutation
The meiotic error that results in aneuploid cells is
nondisjunction
A(n) _________ replaces a codon specifying an amino acid with a stop codon.
nonsense mutation
Determine whether each description pertains to oncogenes and tumor suppressor genes. Drag and drop each description to the appropriate category.
oncogenes: -activation causes cancer -cancer entails a gain-of-function -activation is usually associated with a point mutation, translocation or inversion tumor suppressor genes: -inactivation causes cancer -cancer entails a loss-of-function -often inactivated by a point mutation or deletion
A(n) ________ changes a single base in a DNA sequence.
point mutation
A cell with extra chromosome sets is
polyploid
A mutation that occurs in cells that do not develop into gametes is called a(n) _________ mutation.
somatic
Sporadic cancer is due to _______ mutations
somatic
a _____________ mutation will be present in some of the cells in an individual's body but will be absent from other cells.
somatic
A mutation that occurs during the DNA replication preceding a mitotic cell division is called a
somatic mutation
Cancer cells often have longer telomeres due to reactivation of the enzyme
telomerase
A(n) __________ is a mutation that replaces a purine with another purine or a pyrimidine with another pyrimidine.
transition
In _________, there is an extra copy of one chromosome.
trisomy
In humans, the most frequently seen autosomal aneuploid is
trisomy 21
Expanding trinucleotide repeats usually result in a gain-of-function mutation, often referred to as "dominant toxic gain-of-function."
true
Mutations may not have a distinctive phenotype if they do not affect the coding or the regulatory portion of the genome.
true
Somatic cells may develop mutations in cancer-causing genes.
true
The process of a tumor spreading is called metastasis.
true
