Q1
mcq
1 mark
If the sequence of nitrogen bases of the coding strand in a transcription unit is 5' – ATGAATG – 3', the sequence of bases in its RNA transcript would be
- A. 5' – AUGAAUG – 3'
- B. 5' – UACUUAC – 3'
- C. 5' – CAUUCAU – 3'
- D. 5' – GUAAGUA – 3'
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Q2
mcq
1 mark
How many base pairs will be there in 20 nucleosomes in a DNA double helix ?
- A. 4000
- B. 40
- C. 20
- D. 2000
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Q3
mcq
1 mark
A person with trisomy of $21^{\text{st}}$ chromosome shows
(i) Furrowed tongue
(ii) Characteristic palm crease
(iii) Rudimentary ovaries
(iv) Gynaecomastia
Select the correct option, from the choices given below :
- A. (ii) and (iv)
- B. (i), (ii) and (iv)
- C. (ii) and (iii)
- D. (i) and (ii)
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Q4
mcq
1 mark
Single step large mutation leading to speciation is also called
- A. founder effect
- B. saltation
- C. branching descent
- D. natural selection
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Q5
mcq
1 mark
Observe the schematic representation of assisted reproductive technology given below :
Identify the most appropriate technique depicted in the above diagram.
- A. IUT
- B. IUI
- C. ICSI
- D. ZIFT
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Q6
mcq
1 mark
Match the following genes of the lac operon listed in column ‘A’ with their respective products listed in column ‘B’ :
A
Gene
B
Products
a. ‘i’ gene
b. ‘z’ gene
c. ‘a’ gene
d. ‘y’ gene
Select the correct option :
Options :
a b c d
- A. (i) (iii) (ii) (iv)
- B. (iii) (i) (ii) (iv)
- C. (iii) (i) (iv) (ii)
- D. (iii) (iv) (i) (ii)
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Q7
mcq
1 mark
Which one of the following enzymes a fungal cell should be treated with to get the DNA along with other macro molecules released from it ?
- A. Isozymes
- B. Cellulose
- C. Ribonuclease
- D. Chitinase
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Q8
mcq
1 mark
During biological treatment of sewage, the masses of bacteria held together by fungal filaments to form mesh like structures are called
- A. primary sludge
- B. flocs
- C. activated sludge
- D. anaerobic sludge
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Q9
mcq
1 mark
Which one of the following is not a characteristic feature of “humus” that is formed during decomposition of detritus ?
- A. amorphous, colloidal, dark coloured substance
- B. amorphous, colloidal, light coloured substance
- C. substance resistant to microbial action
- D. colloidal substance
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Q10
mcq
1 mark
Interferons are proteins secreted by
- A. RBC
- B. WBC
- C. Bacteria infected cell
- D. Virus infected cell
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Q11
mcq
1 mark
Identify the correct labellings in the figure of a fertilised embryo sac of an angiosperm given below:
- A. A – zygote, B – degenerating synergids, C – degenerating antipodals, D – PEN
- B. A – degenerating synergids, B – zygote, C – PEN, D – degenerating antipodals
- C. A – degenerating antipodals, B – PEN, C – degenerating synergids, D – zygote
- D. A – degenerating synergids, B – zygote, C – degenerating antipodals, D – PEN
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Q12
mcq
1 mark
Study the pedigree chart of a family showing the inheritance pattern of a certain disorder. Select the option that correctly identifies the nature of the trait depicted in the pedigree chart.
- A. Dominant X-linked
- B. Recessive X-linked
- C. Autosomal dominant
- D. Autosomal recessive
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Q13
mcq
1 mark
Assertion (A): Communities that comprise of more species tend to be more stable.
Reason (R): A higher number of species results in less year to year variation in total biomass.
- A. Both (A) and (R) are true and (R) is the correct explanation of (A).
- B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
- C. (A) is true, but (R) is false.
- D. (A) is false, but (R) is true.
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Q14
mcq
1 mark
Assertion (A): The sugar-phosphate backbone of two chains in DNA double helix show anti-parallel polarity.
Reason (R): The phosphor-diester bonds in one strand go from a $3'$ carbon of one nucleotide to a $5'$ carbon of adjac
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Q15
mcq
1 mark
Assertion (A): In molecular diagnosis, single stranded DNA or RNA tagged with radioactive molecule is called a probe.
Reason (R): A probe always searches and hybridises with its complementary DNA in a clone of cells.
- A. Both (A) and (R) are true and (R) is the correct explanation of (A).
- B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
- C. (A) is true, but (R) is false.
- D. (A) is false, but (R) is true.
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Q16
mcq
1 mark
Assertion (A): AIDS is a syndrome caused by HIV.
Reason (R): HIV is a virus that damages the immune system with DNA as its genetic material.
- A. Both (A) and (R) are true and (R) is the correct explanation of (A).
- B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
- C. (A) is true, but (R) is false.
- D. (A) is false, but (R) is true.
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Q18
short answer
1 mark
Name the restriction enzyme that recognises the given specific sequence of bases. What are such sequence of bases referred to as ?
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Q19
short answer
1 mark
What are the arrows in the given figure indicating ? Write the result obtained thereafter.
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Q20
short answer
3 marks
How is the grazing food chain different from the detritus food chain ?
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Q21
short answer
1 mark
5' – GAATTC – 3'
3' – CTTAAG – 5'
(a) Name the restriction enzyme that recognises the given specific sequence of bases. What are such sequence of bases referred to as ?
(b) What are the arrows in the given figure indicating ? Write the result obtained thereafter.
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Q21
short answer
3 marks
“The detritus food chain may be connected to the grazing food chain at some levels in an ecosystem.” Give an example in support of the statement.
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Q23
short answer
3 marks
If the cells in the leaves of a maize plant contain 10 chromosomes each, write the number of chromosomes in its endosperm and zygote. Name and explain the process by which an endosperm and a zygote are formed in maize.
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Q23
short answer
3 marks
Why must a cell be made ‘competent’ in biotechnology experiments ? How does calcium ion help in doing so ?
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Q24
short answer
3 marks
State the role of “biolistic gun” in biotechnology experiments.
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Q25
short answer
3 marks
Why does DNA replication occur within a replication fork and not in its entire length simultaneously ?
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Q26
short answer
3 marks
“DNA replication is continuous and discontinuous on the two strands within the replication fork.” Explain with the help of a schematic representation.
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Q26
short answer
3 marks
Expression of different genes for different traits may show dominance, incomplete dominance or co-dominance. Write about expression of such genes with the help of one example each.
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Q27
long answer
3 marks
How have biologists tried to explain this in their own ways? Explain.
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Q28
short answer
3 marks
Tropical regions harbour more species than the temperate regions. How have biologists tried to explain this in their own ways ? Explain.
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Q28
short answer
3 marks
Identify a, b, c, d, e and f in the table given below :
Sl. No. Organism Bioactive Molecule Use
1. Monascus purpureus a b
2. c d Antibiotic
3. e Cyclosporin A f
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Q28
short answer
3 marks
Identify $a$, $b$, $c$, $d$, $e$ and $f$ in the table given below:
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Q29
short answer
3 marks
What does an ecological pyramid represent ?
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Q30
short answer
3 marks
The Ecological pyramids may have an ‘upright’ or an ‘inverted’ shape. Justify with the help of suitable examples.
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Q30
long answer
In a human female, the reproductive phase starts on the onset of puberty and ceases around middle age of the female. Study the graph given below regarding menstrual cycle and answer the questions that follow:
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Q30
short answer
1 mark
(a) Name the hormones and their source organ, which are responsible for menstrual cycle at puberty.
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Q30
short answer
1 mark
(b) For successful pregnancy, at what phase of the menstrual cycle an early embryo (upto 3 blastomeres) should be implanted in the uterus (IUT) of a human female who has opted for Assisted Reproductive Technology (ART)? Support your answer with a reason.
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Q30
long answer
2 marks
(c) Name the hormone and its source organ responsible for the events occurring during proliferative phase of menstrual cycle. Explain the event.
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Q30
long answer
2 marks
(c) In a normal human female, why does menstruation only occurs if the released ovum is not fertilised? Explain.
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Q31
short answer
1 mark
(i) Why did Hershey and Chase use $^{35}\mathrm{S}$ and $^{32}\mathrm{P}$ for their experiments?
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Q31
short answer
2 marks
(ii) Write the significance of the following in their experiment: (1) Blending and (2) Centrifugation.
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Q31
short answer
2 marks
(iii) Write the conclusion drawn by them at the end of the experiment.
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Q31
short answer
(a) Natural selection operates in different ways in nature. (i) Identify the type of natural selection depicted in the graph above. (ii) In England after industrialisation, the population of dark winged moths were more favoured than white winged moth. Explain. (iii) Anthropogenic action can enhance the rate of evolution. Explain with the help of an example.
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“Mosquitoes are drastically affecting the human health in almost all the developing tropical countries. Different species of mosquitoes cause very fatal diseases so much so that many humans loose their life and if they survive, are unable to put in productive hours to sustain their life. With the result the health index of the country goes down.”
Q32
short answer
1 mark
Name the form in which Plasmodium gains entry into (1) human body (2) the female Anopheles body.
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Q32
long answer
5 marks
(a) (i) Describe the events of spermatogenesis with the help of a schematic diagram. (ii) Explain the role of hormones in spermatogenesis.
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Q32
short answer
5 marks
(b) (i) Show the development of megaspore mother cell upto the formation of mature embryo sac in flowering plants with the help of labelled diagrams only. (ii) How does geitonogamy differ from xenogamy ? (iii) Name the type of flowers that are invariably autogamous.
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Q33
short answer
2 marks
Why do the symptoms of malaria not appear in a person immediately after being bitten by an infected female Anopheles ? Give one reason. Explain when and how the symptoms will appear.
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Q33
short answer
5 marks
(a) (i) Draw a schematic diagram of the cloning vector pBR 322 and label (1) Bam HI site (2) gene for ampicillin resistance (3) ‘ori’ (4) ‘rop’ gene. (ii) State the role of ‘rop’ gene. (iii) A cloning vector does not have a selectable marker. How will it affect the process of cloning ? (iv) Why is insertional inactivation preferred over the use of selectable markers in cloning vectors ?
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Q33
short answer
5 marks
(b) (i) Name the nematode (scientific name) that infects the roots of tobacco plant and reduces its yield. (ii) Name the vector that is used to introduce nematode-specific genes into the host plant (tobacco). (iii) How do sense and anti-sense RNAs function ? (iv) Why could parasite not survive in a transgenic tobacco plant ?
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