Gauhati University 4th Semester Zoology Major Question Paper

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Gauhati University 4th Semester Zoology Major Question Paper

Gauhati University Zoology Major Question Paper 


2015

ZOOLOGY

( Major )
Theory Paper: M-4.1
Full Marks: 60

The figures in the margin indicate full marks for the questions.

Answer in English.

l. Write True or False: lX7=7

(a) Graffian follicle enlarges and matures under the influence of gonadotrophins.

(b) The fluid medium is one of the fundamental requirement for the encounter of spermatozoa
and egg during fertilization.

(c) The function of the fertilization membrane is to prevent the entry of subsequent spermatozoa.

(d) The blastocoel permits the migration and rearrangement of presumptive organ forming areas during gastrulation.

(e) Presence of excessive amount of yolk leads to meroblastic cleavage.

(f) In mammals, the blastomeres are of different sizes and the number of blastomeres increases by arithmetic progression.

(g) Infiltration is the process in which individual cells detach from the surface of blastoderm and falls into the blastocoel.

2. Write short notes on 2X4=8

(a) Meroblastic cleavage

(b) Corpus luteum

(c) Embryonic induction

(d) Fertilization cone.

3. Write on any three of the following: 5X3=15

(a) Chemical changes during Gastrulation

(b) Cyclic Panhenogenesis

(c) Fate map construction in frog

(d) Chemical changes during cleavage

(e) Neural induction.

4. Describe the process .of oogenesis with the help of suitable diagrams. What are the factors that control oogenesis? 8+2=10

Or

Define fertilization? Describe the process of fertilization with special reference to cortical events. 2+8=10

5. Describe the various stages of Embryonic development of either eye or heart with suitable illustrations. 10

Or

What do you mean by embryonic induction? Describe in details the process of embryonic induction in chordates. 2+8=10

6. What is an organizer? Describe the role of the gray crescent in the process of development.
2+8=10

Or

What is placenta? What are the different types of placenta found according to the arrangement of villi on the blastocyst of mammals? 2+8=lO

2015

ZOOLOGY

(Major)
Theory Paper: M-4.2
Full Marks — 60

The figures in the margin indicate full marks for the questions.

1. Answer the following: l*7=7

(a) Which one of the human chromosomes has the lowest number of genes?

(b) Name the type of point mutations which occur due to insertion or deletion of a single base in DNA causing rest of the codons beyond the point to be read out differently.

(c) Write the base sequences in the nontemplate strand of DNA for the formation of m-RNA having base sequences - UCGGCAGUAAC.

(d) All structural aberrations in chromosomes are produced following chromosome breakage. — Write true or false.

(e) What are the three allelomorphic genes of the wild gene - I (isoagglutinogen) for human blood groups?

(f) Write the modified form of Central Dogma of Biology.

(g) What is the number of crossover and noncrossover chromatids in a tetrad after crossing over?

2. Answer the following briefly: 2X4=8

(a) Who first suggested the triplet nature of Genetic Codes? Write about the degenerate coding system with an appropriate example.

(b) Give a brief account of the mode of inheritance of mitochondrial DNA.

(c) What is meant by the structural genes in a Lac operon? Name different structural genes mentioning the enzymes for which the genes are responsible.

(d) What is the type of radiation the UV-rays are? What components of DNA are the targets of this radiation? Mention two direct effects of UV radiation on DNA molecules.

3. Answer any three questions from the following: 5X3=15

(a) Write about different structural components of a Synaptonemal complex. Mention its role in the process of crossing over. 3+2=5

(b) What is meant by a semiconservative and semi-discontinuous type of DNA replication? Name different components of a replisome and write their role in the DNA replication process. 2+3=5

(c) Distinguish between Back cross and Test cross. Write how a dihybrid test cross ratio is obtained, giving an example. 2+3=5

(d) Explain the genie balance theory of sex determination in Drosophila. 5

(c) Illustrate with an example the preparation of linkage map. In what unit the recombination fiequencies are expressed? 4+1=5

4. Explain various autosomal and sex chromosomal genetic disorders in man. 10

Or

What is polyploidy .? Discuss different kinds of polyploids. Give a brief account on the phenotypic effects of polyploidy in organisms. 1+6+3=10

5. Give a detailed account of the structure and functions of various types of RNA. 10

Or

What do you mean by the mutation in molecular level? Describe various mechanisms of change in the gene at nucleic acid level. 2+8=10

6. What are the two major events of protein synthesis? Discuss how these two events are regulated during biosynthesis of the protein molecule. 2+8=lO

Or

Explain the processes involved in the recombination of genetic materials in bacteria and viruses. 5+5=10