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

Time: 2 hours
Maximum Marks: 50

Note : (i) Answer part I and Part II in separate answer copies

(ii) Draw labelled diagram wherever necessary.

PART I

SECTION A

Note : All the questions of this section are compulsory.

State whether the following statements (1 to 5) are True or False

(i) All the cells of vascular camblum are similar.

(ii) Explant refers to the tissue used to initiate a culture

(iii) The template for exine formation is made up of cellulose.

(iv) Cleistogamous flowers are self pollinated.

(v) Composite endosperm is a characteristic feature of family composite.

SECTION B

Note : Attempt any two questions.

1. Distinguish between any two of the following pairs :(1 x 5 = 5)

(a) Microsporogenesis and Megasporogenesis

(b) Anemochory aid Anemophily

(c) Polyenibryony and Parthenogenesis

(d) Amoeboid tapetum and Secretary tapetum.

2. Draw labelled diagrams of any two of the following:(2 1/2 + 2 1/2 = 5)

(a) L.S of mature, unfertilized ovule.

(b) Cross section of a dicot stem showing heartwood and sapwood.

(c) L.S of lenticel

d) Mature monocotyledonous embryo

3. Write shot notes on any two of the following: (2 1/2 + 2 1/2 = 5)

(a) Devices for cross-pollination

(b) Vivipary

(c) Endosperm haustoria.

SECTION C

1. What is phytochrome ? What developmental phenomena are mediated by phytochrorne ?(1+4 = 5)

OR

Define secondary growth in plants. Give diagrams to deficit secondary growth in a dicot stem.(1 1/2 + 3 1/2 = 5)

2. Highlight some of the important applications of plant tissue culture in agriculture and norticulture.(5)

OR

Describe the current developments in pollen biology.(5)

PART II

SECTION A

Note : Answer all the questions.

1. Fill in the blanks in questions 1, 2 and 3

(i) Merolilastic deavage occurs in the ____ eggs of birds, and the ____ eggs of insects.(1)

(ii) Differentiation of functional erythrocytes occurs under the influence of the hormone ____ secreted in the ____

(iii) Energy for the motility of sperm flagellum is provided by the ____ located in the ____ of spermatozoon.

(iv) Define any two of the following

(a) Chemotaxis

(b) Totipotency

(c) Leukemia.

SECTION B

Note : Answer all the questions in not more than 200 words for each.

1. Write short notes on any two of the following

(i) Activation of sperm

(ii) Prevention of polyspermy in sea urchin

(iii) Apical Ectodermal Ridge (AER)

2. (i) Define emboly.

(ii) Describe the various embolic morphogenetic movements that occur during gastrulation in ernbryos.(1+4)

OR

(i) Define polarity. (1+4)

(ii) Describe the process of regeneration in planariaus with respect to polarity.

SECTION C

Note : Answer any two questions. Answer should not exceed 500 words for each question.

1. Describe the development of lens and comea in the eye of amphibians.

2. Name the hormones produced by the brain, corpora cardiaca, prothoracie gland and corpora allata of insect larvae. Discuss the role of the hormones produced by corpora allata and prothoracie gland(2+3)

3. Draw a schematic diagram to show the menstrual cycle in human females. (No description is required)(5)