BZYCT137 EM 2023 SOLVED ASSIGNMENT

Description

ASSIGNMENT
GENETICS AND EVOLUTIONARY BIOLOGY
Course Code: BZYCT-137
Assignment Code: BZYCT-137/TMA/2023
Maximum Marks: 100
Note: Attempt all questions. The marks for each question are indicated against it.
Part-A Maximum Marks: 50
1. i) How is co-dominance different from incomplete dominance?
ii) Explain the phenomenon of masking the expression of gene by
another in epitasis.
(5)
(5)
2. i) In Drosophila, the recessive, sex-linked genes abnormal eyes facet
(fa) and singed bristles (sn) show 18 percent recombination.
a) If a singed male is crossed to a


fa
fa
female, what phenotypes
are expected in the F1?
b) If the F1 males and females are inbred what phenotypic
proportions would be expected to occur in F2 males and
females?
ii) Two recessive genes ds and mp are present in corn. These are linked
and are 20 map units apart. From the cross:
mp
ds mp ds



 
What percentage of the progeny would be expected to be both ds and
mp in the phenotype?
(5)
(5)
3. a) In the following statements choose the alternate correct word given
in parenthesis.
i) The DNA regions in chloroplast could be observed under
(light microscope/electron microscope).
ii) The regions containing cpDNA are called
(nucleoids/celluloids).
iii) Each nucleoid contains (a single/a few) copies of DNA.
iv) The cpDNA and mtDNA are usually (circular/linear) in nature.
v) Both chloroplast and mitochondria contain (a few/many)
copies of DNA.
vi) The mtDNA of yeast is (bigger/smaller) than mtDNA of
humans.
vii) The occurrence of introns is discovered in (yeast/human).
(7)
4
b) Which among the following statements are correct?
i) Mitochondria contain 80 S ribosomes.
ii) The mRNA encoded by nuclear genes for the smaller subunit
of rubisco is translated in the chloroplast.
iii) The inheritance of chloroplast genome is independent of
nuclear genome.
(3)
4. i) Explain why sterility is common in polyploid organisms?
ii) What is trisomy? By what mechanisms does it come into existence?
(5)
(5)
5. i) Define mutation. Explain the following types of mutations briefly:
(a) Induced mutations
(b) Supperessor mutations
ii) What are transposable genetic elements? How they can cause
mutations?
(5)
(5)
Part-B Maximum Marks: 50
6. Explain Neo Darwinism and Neo Lamarckism in detail. (10)
7. i) Industrial melanism is an excellent model to demonstrate the natural
selection in action. Analyse the above statement critically.
ii) What do you understand by sexual selection. Illustrate your answer
with a suitable example.
(5)
(5)
8. What is Isolation and what are its types? Explain. (10)
9. Answer in about 50 words each.
a) Explain the concept of geographical isolation with suitable
examples.
b) How does habitat preference of organisms promote speciation
process?
c) Cite an example to show that highly restricted breeding seasons of
populations contribute to isolation process.
d) Discuss the role played by courtship behavior and scents in the
isolation process.
e) Distinguish the terms interspecifc sterility and hybrid sterility.
(10)
10. Analyse the causes and influence of big five mass extinctions. (10