Long Answer Type(a) Give any three characters that have developed during human evolution.
(b) Explain the term chemogeny.
(c) Give any two distinctive features of Dryopithecus.
(a) Explain the evolution of giraffe’s neck according to Lamarck’s theory of evolution.
(b) Give two chromosomal similarities between man and apes.
(c) Name any two temporary embryonic structures in vertebrates which provide evidence for evolution.
(a) Persons suffering from sickle cell anaemia are at an advantage in Malaria infested areas. Explain.
(b) Define the term gene flow.
(c) What are analogous organs? Describe with one example from the plant kingdom.
(a) Sickle cell anaemia is an autosomal recessive genetic disorder where normal haemoglobin allele HbA is replaced by HbS, reducing the oxygen-carrying capacity. When the HbS gene is present then the RBCs become sickle shaped/malaria parasite cannot multiply and rupture at low concentration of oxygen/hypoxia leading to severe haemolytic anaemia.
Homozygous individuals having HbS and HbS condition develop the disease and die, but heterozygotes(HbA/HbS) remain normal and are called the carriers of the disease.
The heterozygous individuals were able to cope with malarial infection, better than the persons with normal RBCs because the sickle-shaped haemoglobin were poor host for the malaria parasite as the cell leaked the needed nutrients and was selectively eliminated by the liver. This selective advantage of sickle cell concentrated its occurrence to regions of high malaria incidence and gave the heterozygous individuals an advantage over the others in the case of malaria.
(b) Gene flow is the movement of genes from one population to another as a result of interbreeding between members of the two populations.
(c) Analogous organs are those organs which perform the same function but have different origin and internal structure. They show convergent evolution.
For example - Sweet potato and potato
Sweet potato and Potato have a common function i.e. storage of food in the form of starch, but they both differ in structural origin as the sweet potato is a root tuber while the potato is a stem tuber.
(a) With the help of diagrams, name and describe the different types of placentation seen in angiosperms.
(b) Give four points of anatomical differences between a monocot stem and a dicot stem.
(c) Define the following terms:
(i) Racemose inflorescence
(ii) Osmotic pressure
(a) Draw a diagram of the internal structure of the human ovary.
(b) Define the term water potential.What are its components? Explain.
(c) Give definition and importance of:
(i) Imbibition
(ii) Parturition
(a) Give four adaptations in flowers pollinated by insects.
(b) Describe the mass flow hypothesis for translocation of organic solutes (food) in plants.
(c) Write a brief note on the causes of infertility.
(a) Give any four reasons for Mendel’s success.
(b) Briefly describe the technique employed in DNA fingerprinting.
(c) Give any two features of Genetic Code.
(a) Explain the mechanism of action of T cells to antigens.
(b)Explain how insulin can be produced using recombinant DNA technology.
(c) What is pisiculture? Give one advantage.
(a)Name the causative organism andpreventive measures for each of the following:
(i) Swine flu
(ii) Typhoid
(iii) Filariasis
(iv) Syphilis
(b)State four causes and four consequences of population growth.
(c)Differentiate between:
(i)Cannabinoids and Barbiturates
(ii)Biotic potential and Carrying capacity
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