CLASS XII

BIOLOGY (044)

SAMPLE PAPER-05

Max. Marks 70                                                                                                                           Time allowed: 3 hours

General Instructions:

1) There are a total of 26 questions and five sections in the question paper. All the questions are compulsory.

2) Section A contains question number 1 to 5, Very Short Answer type questions of one mark each.

3) Section B contains question number 6 to 10, Short Answer type I questions of two marks each.

4) Section C contains question number 11 to 22, Short Answer type II questions of three marks each.

5) Section D contains question number 23, Value Based question of four marks each.

6) Section E contains question number 24 to 26, Long Answer type questions of five marks each.

7) There is no overall choice, however, internal choices have been provided in one question of two marks, one question of three marks and all three questions of five marks. An examinee has to attempt any one of the questions out of the two given in the question paper with the same question number.

 

SECTION - A

Question 1:

Mention the characteristics of the pollen grain that make them resistant to physical and biological forces.

Question 2:  

The map distance between gene A and B is 9 units while between B and C is 3 unit, and between A and C is 12 units? Which one of these pairs will show maximum recombination frequency?

Question 3:

The graph given below shows the Species-area relationship. Write the equation of the curve ‘a’.

Question 4:

A pregnant woman was advised to undergo MTP. She was diagnosed by her doctor that the foetus she was carrying in her womb has developed from a zygote formed after the fusion of an XX-egg  with a Y-carrying sperm. Which disorder would the child born will suffer from if the woman does not undergo MTP?

Question 5:

Why is secondary treatment also referred to as ‘biological treatment’?

SECTION - B

Question 6:

What is specific name given to the first milk of early lactation and why is it necessary for the new born?

Question 7:

Give a schematic diagram to show semi-conservative nature of DNA replication. Also name the scientists who experimentally proved this nature of replication.

Question 8:

Write the transcribed mRNA formed from the DNA strand having sequence TAGTACACT. What is the specific term used for the last codon of the mRNA in this case?

OR

How did DDT become ineffective against mosquitoes?

Question 9:

Name the type of bioreactor depicted below in the figure. What is its purpose?

Question 10:

Explain any two functional aspects of an ecosystem.

SECTION - C

Question 11:

Draw a neat and well labeled diagram of a microscopic view of a human sperm.

Question 12:

Describe the lactational amenorrhoea method of birth control.

Question 13:

Explain sex determination in human beings.

Question 14:

What is meant by transcription? Draw a transcription unit showing its three essential regions.

Question 15:

(a) In our body certain body parts like nictitating membrane, vermiform appendix and reduced body hairs are kept under which category?
(b) Can we keep the following parts in the same category as above? Give reasons.
  (i) Defecteive lens due to cataract.
  (ii) Coccyx
  (iii) External ear pinna

Question 16:  

Give two significant differences between the following pairs:

(i) Innate and acquired immunity
(ii) Active and passive immunity
(iii) Antibodies and interferons

Question 17:

Mention the name of the causuative agent, symptoms and the mode of transmission of Amoebiasis.

Question 18:

Define apiculture. State its significance in our lives.

OR

Give the sequence of events followed in Multiple Ovulation Embryo Transfer programme to increase the herd size in cattle.

Question 19:

A team of researchers drew a graph (which is given below) after studying the purity of the waterbody situated close to a factory. Explain the results obtained in the graph, giving reasons, before and after the sewage discharge in the waterbody.

Question 20:

Discuss the role of any three microbes as biofertilisers.

Question 21:

  

(i) Name the organism in which the vector shown is inserted to get multiple copies of the desired genes.
(ii) Identify the region labeled in the vector which is responsible for controlling the copy number of the inserted gene.
(iii) Name and explain the role of selectable marker in the vector shown.

Question 22:

 (i) What are the names given to the three kinds of age profiles depicted above?
(ii) Which one of them is ideal for a population?
(iii) State a reason for your answer in part (ii).

SECTION - D

Question 23:

A married couple, both of whom were colourblind, was worried as they were expecting their first child. They consulted the doctor whether their child too would suffer from colourblindness just like them. The doctor performed some tests and concluded that their child, whether a boy or a girl, would suffer from colourblindness.
(i) What are the values that the doctor promoted in telling the couple about the fate of their child?
(ii) How did the doctor conclude that their child would suffer from colourblindness? What is the genetic basis of this disorder?
(iii) Suppose this couple gave birth to a colourblind boy. What measure should the colourblind boy (in future) take to ensure that his children do not suffer from colourblindness?

SECTION - E

Question 24:

Draw a neat labeled diagram of a transverse section through an mature anther. Also briefly explain the role played by each of its wall layer.

OR

Given below is longitudinal section through a mammalian testis. Study the same and answer the questions that follow:

(i) Label the parts A to D.

(ii) Name the connective tissue sheath surrounding each testis which internally divides the testis into several hundred lobules.

(iii) Which parts mentioned above in the figure are considered as the site of sperm formation and sperm maturation respectively?

(iv) What is the name given to the accessory duct formed by the union of the vas deferens and the duct from the seminal vesicle?

Question 25:

(i) State the law of Independent Assortment.
(ii) In certain plants, the gene for purple stem (P) is dominant over green stem (p) and the gene for red fruit (R) is dominant over yellow fruit (r). If two such plants, heterozygous for both the traits are crossed, state the proportion of offspring expected to have:
(a) Purple stem and yellow fruits.
(b) Green stems and red fruits.
(c) Purple stems and red fruits.

Support your answer by working out a cross.

OR

With the help of a schematic representation, explain the working of lac operon system in E. coli.

Question 26:

What is RNA interference (RNAi)? Explain in detail how this process useful in producing nematode resistant tobacco plants.

OR

(i) Explain in detail the process of decomposition.
(ii) Give a schematic representation of energy flow in an ecosystem.

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