Bachelor of Science (B.Sc.) - Life Science
Term-End Examination

Time: 2 hours
Maximum Marks: 50

Note : Use separate answer books for Part I and Part II. Be brief in your answers. Draw neat and labelled diagrams wherever necessary. All questions from Part I and Part II are compulsory.

PART I

PLANTS

SECTION A

Note : (i) Question 1 is compulsory.

(ii) Draw labelled diagrams wherever necessary.

A1. Fill in the blanks : (5)

(i) The sperm S_va which is associated with the vegetative nucleus, has larger number of ____ .

(ii) A plant hormone which effect cell enlargement is ____ .

(iii) In pineapple the edible part is the proliferated fleshy tissue of ____ in the inflorescence.

(iv) In Asclepiadaceae the pollen grains of an anther lobe are united to form a mass called ____ .

(v) Protuberances of parenchyma cells in the lumen of inactive vessels are called ____ .

(vi) Vascular cambium consists of two histologically distinct kinds of cells, the ____ and the ____ initials.

(vii) The scientist ____ is known for the discovery of cytochrome and the chemical control of organogenesis.

(viii) The only anther wall layer which completely surrounds the locule and has dual origin is ____ .

(ix) The process of embryo development from unfertilized egg is called ____ .

(x) An outgrowth on placenta or funiculus which directs the pollen tube to the micropyle is called ____ .

SECTION B

Note : (i) Attempt any four questions.

(ii) All questions carry equal marks.

B1. Describe the structure and functions of tapetum.

B2. Differentiate between the monocot and the dicot embryos.

B3. Describe the development of endosperm in Loranthaceae.

B4. Explain any two methods used to overcome self incompatibility in plants.

B5. What are the differences in functions of exine and intine ?

SECTION C

Note : Attempt any two questions.

C1. Describe the formation of heart wood. What are the characteristics which determine the properties and uses of wood ? (5)

C2. How are haploid plants produced and what are their uses ? (5)

C3. What is phytochrorne ? How does it regulate plant growth and development ? (5)

PART II

ANIMALS

SECTION A

Note : Answer all questions. Fill in the blanks in questions A1 to A3. (1)

A1. In human development, the implantation of blastocyst outside the uterus is referred to as ____ . (1)

A2. Removal of ____ results in precocious metamorphosis in insects. (1)

A3. In frog's egg, the first cleavage is ____ .

A4. Define any two of the following : (1 x 2 = 2)

(i) Heteromorphisis

(ii) Karyokinesis

(iii) Vitellogenesis

SECTION B

Note : Answer all the questions. Each answer should not exceed more than 200 words.

B1. Write short notes on any two of the following (5)

(a) Types of morphogenetic processes of epithelial cells during organ formation

(b) Intrinsic Growth Factors

(c) Spermiogeneis

B2. Explain the process of lens regeneration from dorsal iris in Triturus (amphibia). (5)

OR

Describe the characteristic features of gastrulation in birds. (5)

SECTION C

Note : Answer all questions. Each answer should not exceed more than 500 words.

C1. (a) Explain the terms hyperplasia, anaplasia and metastasis. (3)

(b) Describe the three stages of carcinogenesis. (2)

OR

Explain the instructive interaction between ectoderm and mesenchyme during the development of feathers in chick. (5)

C2. Describe the process of differentiation of retina in humans. (5)

OR

Describe the process of formation of germinal layers in eutherian mammals. (5)