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QI. Only one answer is correct. Circle the correct letter( 10pts)
1.Comparative genomic hybridization:
a) can detect balanced structural rearrangements b) can detect duplications and deletions
c) uses colour ratios to detect differences in DNA amount d) all of the above are correct
2. Which best describes the action of colcemid in a harvest?
a) inhibiting centriole activity b) inhibiting spindle formation
c) swelling the cell d) none of the above
3. A gamete contains: a) 2n=46 b) 2n=23 c) n=46 d) n=23
4. Mental retardation is associated with the following karyotypes:
a) 47,XY,+21 b) 46,XX,del(4)(p16.3) c) 46,XX,del(15)(q11q13) d) all of the above
5. A single cell with t(7;14)(q34;q11.2) in a synchronized blood culture:
a) indicates that at least 50 more cells should be analysed b) limited mosaicism
c) is a cultural artifact d) All the above
6. Cytogenetic abnormalities identified at spontaneous abortion are represented by:
a) autosomal trisomies b) triploidy d) trisomy 21 e) structural rearrangements f) a, b and e
7. Beginning of human cytogenetics was discovered by Walther Flemming whose:
a)Published illustrations of human chromosomes and referred to chromatin
b) First used term mitosis c) Introduced word chromosome d) a and b
8. Study of chromosomes as cytogenetics was developed by:
a) Flemming b) Watson and Crick c) Mendelian d) Waldeyer
9. The discipline of human cytogenetics is divided into the following periods:
a) Dark ages, Hypotonic, Colchicine and Monosomy
b) Trisomy period and polyploidy
c) Dark ages, Hypotonic , Colchicine and Trisomy
d)Non of the above
10. ------in CGL found for first time the association between chromosomes & cancer:
a)t(11;8) b) del(15p) c) t(9;22) d)dup(1p)
QII. Match the terms in column A with the correct definition terms in column B (10 pts)
Column A / Answer / Column B1-Cytogenetics / Biological specimens coated with fluroscent compounds.
2-Primary constriction / Digesting chromosomes with trypsin
3-Acentric / This deals with the cytological and molecular basis of hereditary, mutation etc
4-G-banding / The total number of chromosomes present in the cell of an organism
5-NORs / Chromosome fragment without centromer.
6-Karyotype / Occupy a constant position relative to the ends of chromosome and which stains slightly.
7-Ploidy / Consist of multiple copies of DNA sequences or genes for the larger fraction (28s)
8-Fluroscence Microscope / Chromosomes ordered by their length, the position of the centromere.
9-Acquired: / Two or more cell lines with different chromosome complements, originating from the same zygote.
10-Mosaicim
/ Associated with a neoplastic or cancer disease process.Q.III. Find out whether the following statements True (√) or False(X):(6pts)
1. Human Chromosome was studied when Hypothesized binding of Giemsa to chromosomes regions and revealed first photograph of chromosome ( )
2. A chromosome consists of two sister chromatids, comprised of a contracted compacted double helix of DNA ( )
3.Centromere, telomere & nucleolar organizing regions interact with the kinetochore during cell division ( )
4. Denver Conference (1960) Proposed Standard System of Nomenclature of Human Mitotic Chromosomes ( )
5. Euchromatin is loosely organized, extended, & uncoiled, contains active, late replicating genes ( )
6. There are two types of heterochromatin; facultative & constitutive heterochromatin( )
QIV. Explain the following findings:(2 pts)
1.FISH using the probes for chromosomes 13, 21, 18, X and Y show 3 signals
for 13, 21 and 18, 2 signals for X and one signal for Y.
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2. A male patient has a blood karyotype of 46,XX in 19/20 metaphases and 47,XXY in one metaphase.
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QV. A female carrier of a reciprocal translocation with the karyotype:
46,XX,t(5;21)(pter;qter) presents for preimplantation genetic diagnosis (PGD)
- You are provided with the following probes for PGD ( 6 pts)
• 5p telomere (green) • 21q telomere (green)
• 21p (ter) ( red) • 5 centromere (red)
List the number of signals and their colors for all possible viable outcomes
Outcome / 5p telomere / 21q telomere / 21p (ter) / 5 centromereQVI. This is a Midterm exam for the Cytogenetic course (240335), so you have studied from Textbook, I presumed!! What is the title of this textbook ?(1pt)
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All the best, Dr. Raida W. Khalil