ISC Class XII Exam Question Papers 2012: Biology

BIOLOGY Paper- 1

THEORY

(Three hours)

(Candidates are allowed additional 15 minutes for only reading the paper.

They must NOT start writing during this time.)

………………………………………………………………………………………………………………………….

 Answer all questions in Part I and five questions from

Part II, choosing three questions from Section A, and two question from Section B.

All working, including rough work, should be done on the

same sheet as, and adjacent to, the rest of the answer.

The intended marks for questions or parts of questions are given in brackets [ ].

 

PART I

Answer all questions

Question 1   [5]

(a) Given one difference between each of the following:

(i) Ventricular systole and Ventricular diastole.

(ii) Sertoli cells and Spermatides.

(iii) Dwarfism and Cretinism.

(iv) Antibodies and Interl~erons.

(v) Glucocorticoids and Mineralocorticoids.

(b) Given reasons for the following:  [5]

(i) Nerve impulse travels in one direction.
(ii) Jamming of wooden doors and windows takes place during rainy season.
(iii) A cut plant wilts fast even if its cut end is dipped in water.
(iv) Urine excreted during summer months is hypertonic.
(v) A person has difficulty in focusing on nearer objects, as the age increases.

(c) Given a scientific term for each of the following:  [5]

(i)  A single isolated contraction of muscle fibre.

(ii) Inhibition of lateral bud growth by terminal bud.

(iii) Spectalised structure through which guttation occurs.

(iv) Development of embryo from the egg without the process of fertilization.

(v) Process of splitting of water molecules during photosynthesis.

(vi) Passing out of urine.

(d) Mention the most significant function of each of the following:   [3]

(i)      Tapetum cell                                            (ii) Serotonln

(iii)    Lenticels                                                   (iv) Cerebrospinal fluid

(v)     Islets of Langerhans                             (vi) Bundle sheath

(e) State the most significant contribution of the following scientists:   [2]

 (i) Hans Berger                                           (ii) Dixon and Jolly
(iii) J.B. Lamarck                                        (iv) William Harvey

(f) Expand the following:    [2]

(i) OP

(ii) RuBP

(iii) IBA

(iv) PEP

PART II
SECTION A
Answer any three questions

Question 2

(a) Given any four anatomical differences between monocotyledonous and  dicotyledonous leaf. [4]

(b) Explain the phases of growth in meristem of plants.   [3]

(c) Draw a neat labelled diagram of a matured anatropous ovule before fertilization.   [3]

Question 3

(a) Given an account of activity of cambium in the secondary growth of the stem.  [4]

(b) Write three differences between C3 and C4 cycles.    [3]

(c) Mention two advantages each of the following:    [3]

(i) Hydroponics (ii) Turgidity to plants (iii) Cross pollination

Question 4

(a) Explain the movement of water cell to cell across the root from the soil to the xylem.  [4]

(b) Draw a labelled diagram ofT. S. of hyaline cartilage. Write a brief note on its functions.    [3]

(c) What is the full form of ADH ? How does ADH control osmoregulation in human  kidney.   [3]

Question 5

(a)    Explain the process of oogenesis in humans.   [4]

{b)   State three difference between red muscle fibre and white muscle fibre.   [3]

(c)    Mention a cause and symptom of each of the following;

(i) Amphysema (ii) Renal calculi (iii) Diarrhoea.

Question 6

Describe the structure of an artery and a vein. Explain how their structure helps in their functioning.

(b) Write three differences between short day and long day plants.

(c) Name the 2nd, 3~d and 8~ cranial nerves in man and write a function of each.

SECTION B

Answer any two questions

Question 7

(a) Explain mass selection and pure line selection. How is pure line selection a better method for crop improvement?   [4]

(b) Write short notes on:   [3]

(i) Atavism (ii) Protoplast fusion (iii) Rh factor

(c)Mention the chromosomal abnormalities concerned with the following conditions in humans:    [3]

(i) Turner’ Syndrome (ii) Klinefelter’s Syndrome
(iii) Down’s Syndrome

Question 8

(a) How does the human body protect itself from infections?    [4]

(b) Write short notes on the following.     [3]

(i) Biomedical Engineering (ii) Stem cells

(iii) Cryopreservation

(c) Give an account of Darwin’s finches.     [3]

Question 9

(a)Explain the convergent and divergent evolution with suitable example.    [4]

(b)What is manure? How does green manure differ from biofertillzers?     [3]

(c)What is IPM? Given an example of bioinsecUcides and bioherbicides and how do they help in pest control.     [3]

Question 10

(a) What is mental illness? Explain any three methods of treatment of mental illness.   [4]

(b) What are Koch’s postulates ? Why are they not applicable to viruses?   [3]

(c) Name the causative agent and the main symptom of each of the following diseases:    [3]

                (i) Filariasis (ii) Rabies (iii) Chicken pox

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