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Lecturer: Dr. Raida W. Khalil
Faculty of Science
Internal examiner:
Department of Biotechnology & Genetic
Engineering
Student Name:
Student Number:
Course Name: Cytogenetic (240335)(section 1)
1st Semester: 2012/2013
Date: 02/12/2012
Midterm Exam Time: 13:10 noon Duration: 60 minutes Number of Pages: 3 Number of Questions:6
 Mark:
/35
(
/30)
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)
All the best, Dr. Raida W. Khalil
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QII. Match the terms in column A with the correct definition terms in column B (10 pts)
Column A
Answer
Column B
1-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.
Associated with a neoplastic or cancer
disease process.
10-Mosaicim
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(
)
All the best, Dr. Raida W. Khalil
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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.
-------------------------------------------------------------------------------------------------------------2. A male patient has a blood karyotype of 46,XX in 19/20 metaphases and 47,XXY in one
metaphase.
---------------------------------------------------------------------------------------------------------------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 centromere
QVI. 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