Civil Services Main Examination 2020 Zoology (Optional) Paper II


Section A

1.(a) What is Wobble hypothesis? How does it explain degeneracy in genetic code? 10
(b)Describe the mechanism of sex determination in Drosophila. 10
(c)Differentiate between sympatric and parapatric speciation with suitable examples.10
(d)Describe the origin of code for zoological nomenclature.10
(e)Describe the sequence specific DNA binding proteins.10


2.(a)Draw an overview of eukaryotic cycle. Describe the role of cyclins in the regulation of cell cycle. 20
(b)What is transgenesis? Describe the methods for gene transfer in animals and its applications. 15
(c)Define paleontology. Discuss the chronological order of elephant evolution.15


3.(a)Define mutation. Describe the types, causes and applications of mutations.20
(b)What is nucleosome? Explain the functional elements of eukaryotic chromosomes.15
(c)What is RAPD? Give an account of the general methods for mapping human genome.15


4.(a)What is Hardy-Weinberg equilibrium? Describe the principles, mechanism and its applications in population genetics. 20
(b)Draw an ultrastructure of plasma membrane. Discuss the roles of lipids in the regulation of membrane fluidity.15
(c)Explain biodiversity. Discuss different grades and factors affecting the distribution of animal biodiversity.15


Section B


5.(a) Describe the basic structure and functions of immunoglobulins. 10
(b)Draw a typical neuron action potential. Discuss the ionic basis for the propagation of nerve impulse. 10
(c) Enlist the composition of salvia. Describe the mechanism of secretion of saliva.10
(d) Give a schematic representation of differentiation of sexual phenotypes during early embryonic development in mammals.10
(e) "Calcium is an initiator of cortical granules reaction." Explain.10


6.(a) Define oxidative phosphorylation. Describe the theories of mechanism of ATP synthesis. 20
(b) What is the general mechanism of blood coagulation? Describe the intrinsic pathway for the initiation of blood clotting.15
(c) What are embryonic stem cells? Discuss the isolation, differentiation and therapeutic applications of embryonic stem cells.


7.(a) Enlist the sources of energy for muscle contraction. Describe the mechanism of contraction of skeletal muscle. 20
(b) "Glycolysis is considered as metabolic hub." Justify.15
(c) What is metamorphosis? Explain the role of thyroxine in the regulation of amphibian metamorphosis.15


8.(a) Define programmed cell death. Explain the molecular mechanism and significance of apoptosis during early embryonic development. 20
(b) What are vitamins? Describe the types and biological roles of fat-soluble vitamins.15
(c) Describe the process of glomerular filtration. Discuss the determinants of glomerular filtration rate in human.15