Unit 5: Chromosome Aberrations Flashcards
Chromosomal mutations are commonly known as ____________?
Chromosomal aberrations
Chromosomal aberrations are essentially abnormalities in:
A. Chromosome number
B. Chromosome structure
C. Both are correct
D. None are correct
C
Which is false about chromosomal aberrations?
A. Arise spontaneously
B. May be chemically induced
C. May be caused by radiation mutagens
D. There are no false statements
D
True or False?
Chromosomal abnormalities give rise to specific physical symptoms, however, these vary in different individuals.
True
Condition wherein affected individual has a total of three sets of each chromosomes (a total of 69 chromosomes)
Triploidy
Condition wherein affected individual has a total of four sets of each chromosomes (a total of 92 chromosomes)
Tetraploidy
Which of the following has more harmful effects?
Trisomy or Monosomy
Monosomy
Variation in _________ include:
Deletion, Duplication, Inversion, Translocation
Chromosome Structure
Type of Aberration
Occur due to loss or rearrangement of the location of the genetic material.
Structural aberrations
Variation in Chromosome structure can occur during the following, except for:
A. Mitosis
B. Meiosis
C. Fertilization
D. All are correct
A
Variation in _________ include:
Aneuploidy
Polyploidy
Chromosome number
It involves the loss of a segment of a chromosome.
Note: May occur anywhere along the chromosome
Deletion
Type of Aberration
Are usually caused by failure in chromosome division
Numerical aberrations
Deletion starts in ________ of chromosomes that may be caused by agents (heat, radiation, viruses, transposable elements) or errors in recombination.
Breaks
Deletions are generally ________ (harmless/harmful) to the affected organism.
Harmful
True or False?
The smaller the deletion, the greater the harm it can cause to an individual.
False
True or False?
Chromosomal deletions can produce acentric chromosomes if the deletion spans over the centromere.
True
What is the syndrome?
Infants have a catlike cry, some facial anomalies, severe mental retardation. Gastrointestinal malformation and abnormal throat structures can also manifest.
Note: Deletion of a portion of the short arm on chromosome 5 (5p-)
Note: Occur in 1 out of 100,000 births.
Cri du chat syndrome
Cri du chat syndrome is a/an _______________ (terminal/interstitial) deletion.
terminal
What does “Cri du chat” translate to?
Cry of the cat
Which of the following bands are not usually deleted in Cri du chat syndrome?
A. 5p15.1
B. 5p15.2
C. 5p15.3
D. All of the above are deleted
A
What is the syndrome?
Rare kidney cancer primarily affecting children; Kidney cells do not mature; Kidney tumors, genital and urinary tract abnormalities
Note: Deletion of a portion of the long arm on chromosome 11 (11q-)
Wilms tumor
What is the syndrome?
Cancer of the eye, increased risk of other cancers; Affecting the nerve cells of the retina
Note: Deletion of a portion of the long arm on chromosome 13 (13q-)
Retinoblastoma
What is the syndrome?
Complex genetic condition affecting many parts of the body. In infants, it causes slow growth. In children and adults, it causes obesity and compulsive eating. Affects the development and function of hypothalamus
Also includes poor sucking reflex, poor sexual development in males, behavioral problems and mental retardation.
Note: Deletion of a portion of the long arm on chromosome 15 (15q-)
Prader-Willi syndrome
Which of the following bands are deleted in Prader-Willi syndrome?
A. 15q11.2-13
B. 15q10.4-14
C. 12q2-3.2
D. 15p2-3.2
A
Chromosomal mutation that results in the doubling of a segment of a chromosome.
Duplication
Form of Chromosome Duplication
Duplicated segment is present in the same orientation immediately adjacent to the original segment of the chromosome.
Note: Able to produce even more copies of the duplicated region
Tandem duplication
Form of Chromosome Duplication
Duplicated segment is present in the opposite orientation (genes are inverted).
Note: May form a loop due to the inverted portion pairing with the normal homologous chromosome segment present on the same arm. May cause dicentric chromatid bridge (anaphase I).
Reverse duplication
Form of Chromosome Duplication
Duplicated segment is present in the same orientation immediately adjacent to the original segment of the chromosome occuring at the end of the chromosome.
Terminal tandem duplication
Chromosomal mutation that results when a segment of a chromosome is excised and then reintegrated in an orientation 180° from the original orientation.
Inversion
Form of Chromosome Inversion
Inversion involving the centromere (chromosome’’s restriction point)
Pericentric Inversion
Form of Chromosome Inversion
Inversion not involving the centromere (chromosome’’s restriction point)
Paracentric Inversion
Chromosomal mutation wherein there is a change in position of chromosome segments and he gene sequences they contain.
Note: No gain or loss of genetic material (unless in interchromosomal translocation)
Translocation
Form of Chromosome Translocation
Change in position of a chromosome segment within same chromosome
Intrachromosomal Translocation