Board Paper of Class 12-Science 2005 Biology Delhi(SET 1) - Solutions
(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?VIEW SOLUTION
- Question 2
In humans, starch digestion begins in the buccal cavity but stops in the stomach. Why?VIEW SOLUTION
- Question 3
Name the two most biodiversity-rich zones of India.VIEW SOLUTION
- Question 4
Name the hormone that makes plants more tolerant to various stresses.VIEW SOLUTION
- Question 5
Name the two major groups of cells required in attaining specific immunity.VIEW SOLUTION
- 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.VIEW SOLUTION
- Question 7
Differentiate between Total Fertility Rate (TFR) and Replacement Level (RL).VIEW SOLUTION
- 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.VIEW SOLUTION
- 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.VIEW SOLUTION
- Question 10
Can all the four chambers of the human heart experience systole simultaneously? Explain justifying your answer.
What do you call the circulatory fluid in the body of cockroach? Mention its three functions.VIEW SOLUTION
- 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.VIEW SOLUTION
- 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?VIEW SOLUTION
- Question 13
Where do PGA and glycine gain entry respectively after being formed during photorespiration in plants? What happens to them immediately after?VIEW SOLUTION
- Question 14
What is meant by bioassay? Name the two bioassays that are used to examine auxin activity in plants.VIEW SOLUTION
- Question 15
Explain CO2 compensation point.VIEW SOLUTION
- Question 16
Define the following and give their values in a normal human adult:
(a) Tidal volume
(b) Expiratory reserve volume
(c) Inspiratory capacityVIEW SOLUTION
- Question 17
(i) How do grasslands differ from Savannas?
(ii) Name the two major categories of plant forms that dominate the desert vegetation.VIEW SOLUTION
- Question 18
Explain the Capillarity Theory in respect of ascent of water in plants. Name the tissue involved.VIEW SOLUTION
- 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?VIEW SOLUTION
- 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.VIEW SOLUTION
- Question 21
Why is sub-culturing essential in plant tissue culture?
Explain the process of heterosis. How is it different from inbreeding depression?VIEW SOLUTION
- 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?VIEW SOLUTION
- Question 23
Distinguish between epimorphic and morphallactic regeneration, giving one example of each.VIEW SOLUTION
- Question 24
Mention where the following are located in the human brain, and give one function of each:
(a) Temporal lobe
(c) Corpus callosumVIEW SOLUTION
- Question 25
Define innate immunity. Name and explain the category of barrier which involves macrophages.VIEW SOLUTION
- Question 26
What is the basis of classifying cancer? Name and explain the different categories of cancer. Mention any two approaches for cancer treatment.
What is embryo culture? What is the objective of this culture? Describe the three applications of this technique.VIEW SOLUTION
- Question 27
Draw a diagram of the longitudinal section of a mature anatropous ovule and label any ten parts in it.
Draw a flowchart to show the hormonal control of the human male reproductive system, highlighting the inhibitory and stimulatory directions in it.VIEW SOLUTION
- Question 28
Explain the process of biosynthetic phase of photosynthesis occurring in the chloroplast.
Describe the process of development of root nodules in a leguminous plant. Name the oxygen scavenger molecule present in the root nodules.VIEW SOLUTION