Long Answer Type(a) Explain giving reasons why the tourists visiting Rohtang Pass or Mansarovar are advised to resume normal active life only after a few days of reaching there.
(b) It is impossible to find small animals in the polar regions. Give reasons.
(a) Tourists visiting high altitude areas such as Rohtang Pass or Mansarovar, experience altitude sickness. Its symptoms include nausea, fatigue and heart palpitations. This is because in the low atmospheric pressure of high altitudes, the body does not get enough oxygen. But, gradually we get acclimatised and stop experiencing altitude sickness. The body compensates low oxygen availability by increasing red blood cell production, decreasing the binding affinity of hemoglobin and by increasing breathing rate. Thus, the visitors are advised to resume their normal active life involving heavy works only after few days because for doing heavy tasks our body needs energy and this energy is obtained by the oxidation of glucose in the presence of oxygen which is a limiting factor in higher altitudes.
(b) Smaller animals are rarely found in Polar Regions because small animals have a larger surface area relative to their volume. Since heat loss or heat gain is a function of
surface area, they tend to lose body heat at a very fast rate when it is cold outside; because of which they have to expend much energy to generate body heat through metabolism.Describe Frederick Griffith’s experiment on Streptococcus pneumonia. Discuss the conclusion he arrived at.
(a) Explain a monohybrid cross taking seed coat colour as a trait in Pisum sativum. Work out the cross upto F2 generation.
(b) State the laws of inheritance that can be derived from such a cross.
(c) How is the phenotypic ratio of F2 generation different in a dihybrid cross?
The following is the illustration of the sequence of ovarian events “a†to “i†in a human female:
(a) Identify the figure that illustrates corpus luteum and name the pituitary hormone that influences its formation.
(b) Specify the endocrine function of corpus luteum. How dies it influence the uterus? Why is it essential?
(c) What is the difference between d and e?
(d) Draw a neat labeled sketch of Graafian follicle.
(a) Why is fertilization in an angiosperm referred to as double fertilisation? Mention the ploidy of the cells involved.
(b) Draw a neat labeled sketch of L.S. of an endospermous monocot seed.
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