Deck 8: Chromosomal Structure and Chromosomal Mutations

Question 1

What are the structures found only at the ends of human chromosomes?

A) Kinetochores
B) Telomeres
C) Centromeres
D) Histones

Answer 1

Telomeres

Question 2

Which of the following is involved in connecting the centromere to the spindles during chromosome segregation in mitosis?

A) Kinetochore
B) Euchromatin
C) Histone protein H1
D) Heterochromatin

Answer 2

Kinetochore

Question 3

Down's syndrome is caused when an extra copy of chromosome 21 is created, which is what kind of genetic event?

A) Gene mutation
B) Chromosome mutation
C) Genome mutation
D) Euploidy

Answer 3

Genome mutation

Question 4

In a C banding pattern, what part of the chromosome stains?

A) Whole chromosome
B) Heterochromatin
C) Euchromatin
D) Centromere

Question 5

A chromosome that has the centromere in the center of the chromosome is called:

A) Acrocentric
B) Telocentric
C) Metacentric
D) Holocentric

Question 6

Chromosomes are divided into different parts, and locations are denoted by numbers corresponding to the different parts in which of the following orders?

A) Sub-band, band, chromosome, region
B) Region, band, sub-band, chromosome
C) Band, chromosome, region, sub-band
D) Chromosome, region, band, sub-band

Question 7

Which of the following types of chromatin are open and actively involved in gene expression (transcription)?

A) Heterochromatin
B) Homochromatin
C) Euchromatin
D) Interchromatin

Question 8

Human chromosomes 21 and 22 are described as which of the following with regard to the location of the centromere?

A) Telocentric
B) Holocentric
C) Metacentric
D) Acrocentric

Question 9

A nucleosome consists of DNA and which of the following combinations of histone proteins?

A) 2(H1), 2(H2A), 2(H3), 2(H4)
B) 2(H2A), 2(H2B), 2(H3), 2(H4)
C) 2(H1), 2(H2A), 2(H2B), 2(H4)
D) 2(H2), 2(H3), 2(H4), 2(H5)

Question 10

Examination of chromosomes in karyotypes is performed on chromosomes in what stage of mitosis?

A) Prophase
B) Metaphase
C) Interphase
D) Telophase

Question 11

How is high-resolution banding achieved?

A) Increase the concentration of Giemsa.
B) Stain the chromosomes longer.
C) Stain the chromosomes at low temperatures.
D) Stain the chromosomes before maximal condensation.

Question 12

A change in DNA sequence that is present in at least 1% to 2% of the population is called a(n):

A) Phenotype
B) Polymorphism
C) Aneuploid
D) Mutation

Question 13

The short arm of the chromosome is designated as which of the following?

A) o
B) p
C) q
D) r

Question 14

A reciprocal translocation is which type of mutation?

A) Gene
B) Genome
C) Chromosome
D) Nucleotide

Question 15

When chromosomes are stained with Giemsa, the resulting bands are called:

A) G bands
B) Q bands
C) R bands
D) C bands

Question 16

A polymorphism is distinguished from a mutation in what way?

A) Its frequency in a given population
B) The size of the genetic region involved
C) The severity of effect on phenotype
D) Associations with other genetic events

Question 17

What is a phenotype?

A) The structure of a gene
B) A trait resulting from gene transcription and translation
C) The nucleotide sequence responsible for a genotype
D) A change in the gene structure

Question 18

What is the designation of a cell with three copies of every chromosome?

A) Euploid
B) Diploid
C) Triploid
D) Tetraploid

Question 19

Which is the proper order for the four phases of the cell cycle?

A) G1, S, M, G2
B) G1, S, G2, M
C) G2, S, M, G1
D) M, S, G1, G2

Question 20

Colcemid is used in the procedure of preparing a chromosome spread for karyotype analysis to do which of the following?

A) Spread the chromosomes out within the cell
B) Inhibit microtubule formation
C) Induce cells to enter mitosis
D) Fix cells to the slide prior to staining

Question 21

In spectral karyotyping, each of the 23 chromosomes is distinguished by:

A) Size
B) Degree of staining
C) Fluorescent color
D) Position

Question 22

A chromosome formed when parts of two or more chromosomes are joined to a third normal chromosome is called a(n):

A) Ring chromosome
B) Isochromosome
C) Derivative chromosome
D) Balanced translocation

Question 23

Before its conversion to a microarray technique, CGH was performed by hybridizing labeled DNA to what support?

A) Immobilized PCR products
B) Normal chromosome spread
C) Nitrocellulose membrane
D) Agarose gel

Question 24

Which of the following would be most difficult to identify by karyotype?

A) Microdeletion
B) Reciprocal translocation
C) Aneuploidy
D) Polyploidy

Question 25

Comparative genome hybridization detects which type of genetic abnormalities?

A) Amplifications relative to reference DNA
B) Absolute gene numbers
C) Inversions
D) Amino acid substitutions

Question 26

Which of the following is an advantage of interphase FISH as compared with metaphase FISH?

A) Examination of 20 spreads in interphase FISH has increased sensitivity.
B) One can identify mutations anywhere in the chromosome in interphase FISH.
C) Interphase FISH allows identification of all chromosomes.
D) Results are available faster in interphase FISH procedures than metaphase FISH procedures.

Question 27

Interphase FISH has been performed on a patient sample. With a chromosome 8 centromeric (CEP 8) probe, two signals are observed in each spread examined. A probe for the immunoglobulin heavy chain region on chromosome 14 gives two distinct signals per nucleus, and a probe for the myc gene on chromosome 8 gives two distinct signals per nucleus. Which of following interpretations is correct?

A) The patient is normal.
B) The patient has a t(14;8) translocation.
C) The patient has a chromosome 8 deletion.
D) The patient has a chromosome 8 insertion.

Question 28

A medical laboratory scientist performs fluorescence in situ hybridization (FISH) on interphase chromosomes using a probe to chromosome 21. In all cells examined, two signals were seen. These results are interpreted as:

A) Normal
B) Abnormal; the patient has Down's syndrome
C) Abnormal; the patient is lacking a copy of chromosome 21
D) Abnormal; the patient has a Philadelphia chromosome

Question 29

The karyotype of a normal male is designated by which of the following?

A) 46, XX
B) 46, XY
C) 47, XX
D) 47, XY

Question 30

An exchange of genetic material between chromosomes is called a(n):

A) Deletion
B) Inversion
C) Insertion
D) Translocation