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

Time: 2 hours
Maximum Marks: 50

(ii) Draw labelled diagrams wherever necessary.

PART I

Plant

SECTION A

Note : Section A is compulsory.

A1. State whether the following statements [(i)-(v)] are true or false (5)

(i) The function of endothecium is to provide nourishment to the microspores.

(ii) Female gametophyte produces triploid embryo and diploid endosperm in angiosperms.

(iii) Schizocarpic fruits are those that develop from multicarpellary ovaries that separate on maturity into individual achenes, each representing a carpel.

(iv) Antipodal cells are absent in oenathera type of embryo sac.

(v) Potyteny refers to an increase in the number of chromonemata per chromosome.

SECTION B

Note : Attempt any two questions.

B1. Distinguish between any two of the following pairs (5)

(a) Cellulose and Callose

(b) Parthenocarpy and Parthenogenesis

(c) Orthotropous and Anatropous ovule

(d) Cellular and Helobial endosperm

B2. Draw labelled only diagrams of any two of the following : (5)

(a) L.S. of cotton seed (kernel).

(b) Cross section of the fruit of Pyrus malus (apple).

(c) Fine-structure of growing pollen tube.

B3. Attempt any two of the following (5)

(a) What is double fertilization ? Explain its significance.

(b) Enumerate the functions of synergids.

(c) What are the incompatibility factors and the site of their action in gametophytic and sporophytic incompatibility ?

(d) Describe the methods for overcoming seed dormancy.

SECTION C

Note : Answer all questions.

C1. Explain the significance of apical dominance. What are the chemical factors that control apical dominance ?

OR

Describe the structure and function of pariderm

C2. Describe how a vegetative apex is transformed into a floral apex.

OR

What are the industrial applications of plant cell culture technique ?

PART II

Animal

SECTION A

Note : Answer all questions. Fill in the blanks of questions A1, A2 and A3.

A1. With respect to the quantity of yolk the eggs in eutherian mammals are ____ . (1)

A2. The port of coelom that surrounds the heart in called ____ cavity. (1)

A3. ____ is the ability of malignant cell to detach itself from a tumour and establish a tumour at another site. (1)

A4. Differentiate between any two pairs of the following terms : (2)

(a) Progressive changes and Regressive changes

(b) Isogamy and Anisogamy

(c) Holoblastic cleavage and Meroblastic cleavage

SECTION B

Note : Answer any two of the following questions. Limit each answer to 200 words.

B1. (a) Explain the term epimorphosis.

(b) Describe the process of regeneration in Hydra (2 + 3 = 5)

B2. (a) Name the glands of insect larva that secrete (i) juvenile hormone and (ii) ecdysone.

(b) Describe the interaction of hormones in the process of insect metamorphosis. (5)

B3. Write short notes on any two of the following :

(a) Vital Dye Staining

(b) Involution

(c) Role of hormones in aging

SECTION C

Note : Answer any two of the following questions. Each answer should not exceed more than 500 words.

C1. With the help of a suitable diagram describe the menstrual cycle in a human female. (5)

C2. Describe the stages of carcinogenesis. (5)

C3. Describe the process of gastrulation in chick embryo. (5)