Download LSE-03

ASSIGNMENT BOOKLET
Assignment Booklet
2005
Application Oriented Course
In
Human Environment
Bachelor’s Degree Programme
Bachelor Degree Programme in Science
(B.Sc.)
GENETICS
ASSIGNMENTS 2005
ASSIGNMENT 1 – TMA 1
ASSIGNMENT 2 – TMA 2
ASSIGNMENT 3 – TMA 3
SCHOOL OF SCIENCES
Indira Gandhi National Open University
Assignments 1, 2 and 3
Maidan Garhi
2005
New Delhi – 110 068
Dear Students,
1
LSE-03
Dear Student,
You would be doing two Tutor Marked Assignments (TMAs) for the Genetics Course (LSE-03).
The block wise distribution of the assignments is as follows:
TMA-1
TMA-2
Block 1, 2
Block 3, 4
The instructions for doing the assignments are provided in the Programme Guide under
Section 7.1 ‘Assignments’. Do read the instructions carefully before starting your work.
Submit your assignment responses as follows:
Assignment No.
Date of Submission
Where to Send
TMA– 1
6 weeks after receiving the
printed material with
assignments.
The Coordinator of your
study centre.
TMA– 2
10 weeks after receiving the
printed material with
assignments.
The Coordinator of your
study centre.
 Answer sheets received after the due date shall not be accepted.
 Please retain a copy of your assignments.
Wishing you good luck.
Course-Team (LSE-03)
2
TMA-1
Course Code: LSE-03
Assignment Code: LSE-03/ TMA-1/ 2005
Maximum Marks: 100
1.
a) What is a test cross?
b) With help of an example show how a test cross can be used to confirm the Law of
Segregation.
2.
3.
(2+3)
a) Make a comparison between codominance and incomplete dominance citing an example
for each.
b) Under which conditions can a classic Mendelian 9:3:3:1 ratio be converted into 9:7 ratio?
(2+3)
a) Discuss the sex determination mechanism in Drosophila.
b) Identify the sex of the following individuals of Drosophila:
i) XXAA
ii) XXAAAA
iii) XXXXAAA
iv) XXXAAAA
4.
(6+4)
a) Explain with the help of an example the inheritance of X-linked dominant genes in
humans.
b) A couple have a colour blind daughter and a son with normal vision. What could be the
genotypes of their parents?
(5+5)
5.
a) What are sex mosaics? With the help of diagrams only depict the formation of mosaics
due to mitotic nondisjunction.
(2+3)
b) Different sex ratios occur for different age groups in humans. Discuss this statement.
(5)
6.
What is crossing-over? When does it occur? Discuss the molecular model of crossing-over.
(3+3+4)
7.
Explain how you would determine whether a particular inheritance is controlled by
cytoplasmic factors.
(8)
8.
Describe the procedure of making chromosome preparations for cytogenetic studies.
(10)
9.
Distinguish between hetero- and eu-chromatin.
(2)
10. a) Name two types of inversions and the parts of the chromosome they involve.
b) What is an unbalanced translocation?
c) What is meiotic nondisjuction?
d) Why are trisomics and nullisomics less frequent in nature?
3
(2+1+1+2)
11. With the help of two examples, explain how polyploidy has been applied for the benefit of
human beings.
(5)
12. The following chromosomal abnormalities in individuals are the result of meiotic
nondisjuction:
47 + XXX
47 + XYY
48 + XXXX
49 + XXXXY
a) Indicate the expected phenotypic sex corresponding to each of the above abnormal
chromosomal combinations in human beings.
b) How many Barr bodies would be there in the cells of each of the above abnormalities?
(2+2)
13. a) Describe the experiment that conclusively demonstrated that DNA is the genetic
material.
b) What scientific information was available to Watson and Crick that led them to propose the
double helix model for DNA?
(5+5)
14
a) What is F factor?
b) How does an Hfr cell differ from an F+ cell?
c) When a Strain A which is pur+ gal– is mixed and cultured with Strain B which is
pur–gal+ the progeny was found to the pur+gal+. What inference would you draw from
this experiment?
(1+2+2)
--x--
4
TMA-2
Course Code: LSE-03
Assignment Code: LSE-03/ TMA-2/ 2005
Maximum Marks: 100
1.
a) Using the phage T4 as a genetic tool comment on the fine structure of gene.
b) Differentiate between the following:
i) Intergenic and intragenic mapping,
ii) Complementing and non-complementing mutations.
2.
(5)
(2½ + 2½)
a) How can inducible and repressible enzymes of microorganisms be distinguished?
b) Of what biological significance is the phenomenon of catabolite repression?
(2+3)
3.
What is a homeobox? Briefly explain the significance of homeotic genes in the development
of eukaryotes.
(2+3)
4.
Describe five ways by which mutations can occur in DNA base sequences.
5.
a) Draw a labelled diagram of a RNA virus.
(5)
b) Explain the mode of action of RNA virus in cellular transformation.
c) Name two chemical teratogens and mention the abnormalities they cause.
6.
7.
8.
(3+5+2)
a) List any four types of cells involved in cell-mediated immunity.
(2)
b) Write the functions of these cell types.
(4)
c) What is Precipitin Reaction? Explain.
(1+3)
a) Describe the incompatibility in ABO system of blood group.
b) Briefly describe the hemoglobin gene clusters.
(3+2)
a) Define the following terms:
i) Adaptive value
ii) Selection coefficient
iii) Genetic drift
iv) Gene flow
b) An allele has an adaptive value of 0.45. What is its Selection coefficient?
c) Explain with the help of an example how genetic drift affects gene frequencies in
populations.
(4+1+5)
9.
If the height in humans is determined by the genes X and Y and their alleles x and y, what will
be the genotypes and phenotypes of the children whose parents are of intermediate height?
Make a Punnett Square to depict the results. You may classify their phenotypes in the
following five categories: very tall, tall, intermediate, short, and very short.
(10)
5
10. What is the use of Twin Studies in applied genetics?
(5)
11. Write an essay on “Genetics of Human Behaviour”
(10)
12. a) What is genetic counselling and how does it aid in human welfare?
b) Discuss any two applications of genetic engineering.
(1+2)
(2)
13. a) Briefly discuss the mechanism of Ti plasmid mediated transformation of plant cells.
b) Write any two applications of this process in plant biotechnology.
14. What is antisense RNA? Discuss its significance in plant biotechnology.
--x--
6
(3+2)
(2+3)
7