Board Paper of Class 12-Science 2005 Biology (SET 1) - Solutions
General Instructions:
(i) All questions are compulsory.
(ii) This question paper consists of four sections A, B, C and D.
Section A contains 5 questions of one mark each.
Section B is of 10 questions of two marks each.
Section C is of 10 questions of three marks each and
Section D is of 3 questions of five marks each.
(iii) There is no overall choice. However, an internal choice has been provided.
(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.
- Question 1
What would happen to the rate of photosynthesis in C3 plants if the CO2 concentration level almost doubles from its present level in the atmosphere?
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- Question 2
In humans, starch digestion begins in the buccal cavity but stops in the stomach. Why?
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- Question 3
Name the
two most biodiversity-rich zones of India.
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- Question 4
Name the hormone that makes plants more tolerant to various stresses.
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- Question 5
Name the
two major groups of cells required in attaining specific immunity.
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- Question 6
Name the end products of aerobic and anaerobic glycolysis. List two ways by which molecules of ATP are produced in glycolysis during aerobic respiration in a cell.
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- Question 7
Differentiate between Total Fertility Rate (TFR) and Replacement Level (RL).
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- Question 8
Due to
uncontrolled excessive hunting, the population of tigers in a forest
becomes zero. Discuss the long-term effects of this situation on the
population of deer in that forest.
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- Question 9
Name the source gland of leutinising hormone (LH). Mention the other hormone along with which it acts on its target cells/organs. Give their two functions.
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- Question 10
Can all the four chambers of the human heart experience systole simultaneously? Explain justifying your answer.
OR
What do you call the circulatory fluid in the body of cockroach? Mention its three functions.
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- Question 11
Why do scientists pick hydrogen as the basis for MRI scanning? Name a part of the human body that does not appear in an MRI scan.
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- Question 12
What is thermal stratification? How does thermal stratification in temperate lakes help in rich growth of phytoplanktons during autumn and spring turn-over?
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- Question 13
Where do PGA and glycine gain entry respectively after being formed during photorespiration in plants? What happens to them immediately after?
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- Question 14
What is meant by bioassay? Name the two bioassays that are used to examine auxin activity in plants.
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- Question 16
Define the following and give their values in a normal human adult:
(a) Tidal volume
(b) Expiratory reserve volume
(c) Inspiratory capacity
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- Question 17
(i) How do grasslands differ from Savannas?
(ii) Name the two major categories of plant forms that dominate the desert vegetation.
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- Question 18
Explain the Capillarity Theory in respect of ascent of water in plants. Name the tissue involved.
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- Question 19
Explain the initiation of muscle contraction. What is the role of Sarcoplasmic Reticulum, Myosin head and F-action during contraction in striated muscles?
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- Question 20
What is
meant by ozone shield? Name two gases that can cause damage to this
shield. Give one harmful effect of this damage each on plants and
animals.
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- Question 21
Why is sub-culturing essential in plant tissue culture?
OR
Explain the process of heterosis. How is it different from inbreeding depression?
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- Question 22
Where and how is urea produced in ureotelic animals? What happens to the kidney filtrate in descending loop of Henle and collecting tubules in humans?
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- Question 23
Distinguish between epimorphic and morphallactic regeneration, giving one example of each.
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- Question 24
Mention
where the following are located in the human brain, and give one
function of each:
(a) Temporal lobe
(b) Cerebellum
(c) Corpus callosum
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- Question 25
Define
innate immunity. Name and explain the category of barrier which
involves macrophages.
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- Question 26
What is
the basis of classifying cancer? Name and explain the different
categories of cancer. Mention any two approaches for cancer
treatment.
OR
What is
embryo culture? What is the objective of this culture? Describe the
three applications of this technique.
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- Question 27
Draw a
diagram of the longitudinal section of a mature anatropous ovule and
label any ten parts in it.
OR
Draw a
flowchart to show the hormonal control of the human male reproductive
system, highlighting the inhibitory and stimulatory directions in it.
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- Question 28
Explain the process of biosynthetic phase of photosynthesis occurring in the chloroplast.
OR
Describe the process of development of root nodules in a leguminous plant. Name the oxygen scavenger molecule present in the root nodules.
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