Q28 of 30 Page 1

(a) Draw a labelled diagram of the human female reproductive system.

(b) Enumerate the events in the ovary of a human female during:


(i) Follicular phase


(ii) Luteal phase of menstrual cycle
OR


(a) Write the specific location and the functions of the following cells in human males:


(i) Leydig cells


(ii) Sertoli cells


(iii) Primary spermatocyte


(b) Explain the role of any two accessory glands in human male reproductive system.


The human female reproductive system includes: a pair of ovaries along with a pair of oviducts, uterus, cervix, vagina and the external genitalia. The female external genitalia include mons pubis, labia majora, labia minora, hymen and clitoris.

a)


b)


v Follicular Phase (Proliferative Phase)


Ø It is a 6 to 7 period in the cycle .


Ø FSH is secreted which stimulates release of estrogen.


Ø Proliferation of endometrium takes place.


Ø Endometrium becomes thick and increase in glands and vessels takes place in the wall/lining.


v Luteal Phase (Secretory Phase) :-


Ø It is a approx 13 day period in the cycle, from 15th to 28th day.


Ø LH surge and ovulation takes place.


Ø Corpus luteum is also formed which releases progesterone in large amount.


Ø Watery mucus secretion by vaginal glands increases.


Ø Endothelium is maintained for implantation.


Ø If fertilization does not take place then corpus luteum degenerates and endothelium disintegrates.


OR


a)


i) Ledig cells :- Ledig cells are also known as interstitial cells .These are present in the interstitial space outside the seminiferous tubules. Function of ledig cells is to synthesise and secrete testicular hormone called " Androgen".


ii) Sertoli cells:- Sertoli cells are present in the inner lining of seminiferous tissue. It’s function is to provide nutrition to spermatids, and is thus also called as ‘Nurse Cell’. iii)Primary Spermatocyte :- It causes the initiation of meiosis and formation of 2 haploid secondary spermatocytes.


b) The role of male accessory glands are :-


i) Secretion of seminal gland is rich in fructose, calcium and some enzymes which help in survival and motility of sperms.


ii) Secretion of bulbourethral gland helps in lubrication of penis.


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26

How can crop varieties be made disease resistant to overcome food crisis in India? Explain. Name one disease resistant variety in India of:

(a) Wheat to leave and stripe rust


(b) Brassica to white rust


OR


Write the source and the effect on the human body of the following drugs:


(i) Morphine


(ii) Cocaine


(iii) Marijuana


 27

Name the type of interaction seen in each of the following examples:

(i) Ascaris worms living in the intestine of human.


(ii) Wasp pollinating fig inflorescence.


(iii) Clown fish living among the tentacles of se-anemone.


(iv) Mycorrhizae living on the roots higher plants.


(v) Orchid growing on a branch of a mango tree.


(vi) Disappearance of smaller barnacles when Balanus dominated in the Coast of Scotland.


 29

Explain the salient features of Hugo de Vries theory of mutation. How is Darwin’s theory of natural selection different from it? Explain.

OR


(a) Name the primates that lived about 15 million years ago. List their characteristic features.


(b) (i) Where was the first man-like animal found?


(ii) Write the order in which Neanderthals, Homo habilis and Homo erectus appeared on earth. State the brain capacity of each one of them.


(iii) When did modern Homo sapiens appear on this planet?


 30

(a) Explain primary productivity and the factors that influence it.

(b) Describe how to oxygen and chemical composition of detritus control decomposition.


OR


(a) What is El Nino effect? Explain how it accounts for biodiversity loss.


(b) Explain any three measures that you as an individual would take, to reduce environmental pollution.