Model Question Paper www.gbshse.gov.in Goa Board of Secondary and Higher Secondary Education Plus Two, 12th Std, +2, HSc : Biology

[hemalathaijt]

Document Described : Goa Board of Secondary and Higher Secondary Education
MODEL QUESTION PAPER
SUBJECT; BIOLOGY
Max Marks: 70 CLASS : XII Time: 3 Hrs

http://gbshse.gov.in/
http://gbshse.gov.in/documents/MODEL%20QUESTION%20PAPER(BIOLOGY%20XII).doc

Instructions
i)All questions are compulsory
ii)Answer each main question on a fresh page.
iii)Write numbers of the main questions and sub questions clearly.
iv)Draw neat diagram wherever specified in lead pencil only.
v)The question paper consists of 07 main questions.
vi)There is no overall choice. However internal choice has been provided in one questions carrying 05 marks.

Q.1. A) Ovulation in human is induced by a hormone called (1)
a. Estrogen
b. L.H.
c. Progesterone
d. F.S.H.
B) Draw a neat diagram of Isogametes of Cladophora.(1)
C) Draw a neat diagram of L.S. of a flower showing the position and arrangement of various floral organs.(2)
D) Draw a neat diagram of an enlarged seminiferous tubule.(2)
E) On experimental basis the polar nuclei were clipped. Predict the effect of this on embryo development.(2)
F) Give a brief account of the process of spermatogenesis in humans.(2)

Q.2. A) Strength of linkage is inversely proportionate to distance between(1)
a. chromosomes
b. Genes
c. Telemeres
d. Chromatids
B) In the case of a couple having two girls, what is the percentage of probability of the third child to be a girl?(1)
C) Draw a neat diagram showing Watson-Crick model for semi-conservative DNA replication.(2)
D) Give the salient features of Southern blot hybridization technique for DNA finger printing.(3)
E) With a suitable example derive the phenotypic and genotypic ratio in a Monohybrid cross.(3)

Q.3.A) Select the correct answer:
Mr. Raj, a drug addict discontinued regular consumption of cocaine. He now manifests a condition called(1)
a.Hallucination
b.Downs Syndrome
c.Withdrawal Syndrome
d.Depression
B) The apple juice that Seema prepared at home appeared very turbid as compared to the commercial preparations available in the market. Why?(1)
C) The tears in our eyes are an excellent physiological barrier. Give reason.(1)
D) Briefly explain the mode of replication of the HIV virus.(2)
E) Give a brief account of the various forms of treatment for cancer.(2)
F) Write a short note on the role of Microbes as biofertilizers.(3)

Q.4.A) Transgenic animals are those which have
a. Foreign DNA in some of their cells.
b. Foreign DNA in all of their cells.
c. Foreign RNA in all of their cells.
d. Both (a) and (c).(1)
B) BT toxin produced by Bacillus Thuringiensis kills cotton boll worm but has no effect on Bacillus itself. Why?(1)
C) What is Gene Therapy? Explain how it can be used to cure adenosine deaminase (ADA) deficiency.(3)
D) Explain in detail the process of recombinant DNA technology.(5)
OR
E) What are the features required to facilitate cloning into a vector. Explain(5)