They normally flower in the late spring or early summer<\/li>\n<\/ul>\nFunction:
\n(c) 2nd \u2014 Optic \u2014 Vision
\n3rd \u2014 Oculomotor \u2014 Movement of eyeball, accommodation
\n8th \u2014 Auditory \u2014 Hearing and body balance<\/p>\n
Section – B
\n(Answer any two questions)<\/p>\n
Question 7.
\n(a) Explain mass selection and pure line selection. How is pure line selection a better method for crop Improvement? (4]
\n(b) Write short notes on [3]
\n(i) Atavism
\n(ii) Protoplast fusion
\n(iii) Rh factor
\nAnswers:
\n(a) Mass selection – Most common and old method of crop selection. In this selection, large num-ber of similarly appearing plants are selected for the desired trait and their seeds are mixed together which is then sown to raise new crops.<\/p>\n
Pure line selection : It is the progeny of a single homozygous self-pollinated plant. The single plant of the desired trait is selected out of the variable populate in the field. Seeds from the selected plants are sown in different rows to produce progeny by self-pollination.
\nPure line selection is better method because the selected plants retain desirable characters for several generation.<\/p>\n
(b) Write notes on:
\n(i) Atavism: Reappearence of certain ancestral characters which had either disappeared or were reduced.
\n(ii) Protoplast Fusion : It is also called somatic fusion. It is the genetic modification in plants by which protoplasts of two distinct species fuses to form somatic hybrid.
\n(iii) Rh factor: The erythrocytes of most people have an agglutinogen named the Rh factor. It was first found in rhesus monkey. Such peoples are called Rh-positive. The minority with no such agglutinogen are known as Rh-negative. When the donor\u2019s blood is incompatible with the recipients blood in Rh-factor, transfusion of such blood results in destruction of erythrocytes.<\/p>\n
(c) (i) Turner\u2019s syndrome : Individual has 45 chromosomes (44+X) i.e. one chromosome less than normal and hence sterile female.
\n(ii) Klinefelter\u2019s Syndrome : This disorder is due to XXY genotype. Such an individual has 47 chromosomes (2n +1) and the male is sterile with underdeveloped testes.
\n(iii) Down\u2019s syndrome : This disorder is associated with an extra chromosome 21. Such indi-viduals have 47 chromosomes (45 + XX in female and 45 + XY in male)<\/p>\n
Question 8.
\n(a) How does the human body protect itself from infections? [4]
\n(b) Write short notes on the following : [3]
\n(i) Biomedical Engineering
\n(ii) Stem cells
\n(iii) Cryopreservation
\n(c) Give an account of Darwin\u2019s finches. [3]
\nAnswer:
\n(a) Human body has two lines of defence against pathogens :
\n1. Non-specific mechanism
\n2. Specific mechanism (Immune System)<\/p>\n
1. Non-specific defence mechanism – It is of two types
\n(a) external defence or 1st line of defence and
\n(b) internal defence or 2nd line of defence
\n(a) Skin, mucus membrane lying the respiratory tract, throat, digestive tract and urinogenital system is the first line of defence. It secretes certain chemicals which inhibits the growth of pathogens.
\n(b) Body\u2019s second line of defence is carried on by white blood corpuscles, macrophages, mast cells, inflammatory reactions and fever.<\/p>\n
2. Specific mechanism – This mechanism is also called immune system which has two com-ponents 1. humoral immune system (Antibody-mediated immune system) and 2. cell-mediated immune system (defends the body against pathogens-protists and fungi)<\/p>\n
(b) (i) Biomedical Engineering – It is the branch of science which deals with the instruments
\nused in diagnosis and the treatment of human diseases. The instruments are classified into following three categories :
\n1. Diagnostic instrument
\n2. Imaging instrument
\n3. Therapeutic instrument.<\/p>\n
(ii) Stem cell – These cells can divide and differentiate into diverse specialised cell type and self.
\n(iii) Cryopreservation – It is the storage of living organisms in ultra-low temperature such that it can be revived and restored into the same living state as before it was stored.<\/p>\n
(c) Darwin\u2019s finches : The islands situated near the mainlands usually possess flora and fauna related to those of mainland. However, they have a unique diversity of species despite being related. One such example is Galapagos islands (Spanish Galapago – Giant Tortoise). Darwin visited the island in 1835 and described them as living laboratory of evolution. The islands have 26 species of birds and 11 species of tortoises. Out of 26 species of birds, 23 are endemic or found only in the islands. Amongst them were species of sparrow-like small black birds called finches. They are called Galapagos finches or Darwin\u2019s finches (Lack, 1947).<\/p>\n
They resemble mainland finches in plumage, body plan and short tails but differ amongst themselves as well as from mainland finches in shape and size of beaks, food habits, colour of feathers and body size. Thirteen species of finches occur in Galapagos island and one species in nearby Cocos island. Six species are of ground finches (Geospiza species), six species of tree finches (Camarhyncus species) and two types of warbler finches (Certhidia and Pinarolaxis species). The ancestors of Galapagos finches must have come from mainland.<\/p>\n
They were seed eating. However, environment and availability of food on the various islands were different from those of the mainland. As a result variations appeared in them to suit their habitats. They ultimately produced the different species of finches, some of which evolved insect eating patterns. Divergence of organisms of a common stock due to adaptive changes to suit new environmental conditions is called adaptive radiation.<\/p>\n
Question 9.
\n(a) Explain the convergent and divergent evolution with suitable examples. [4]
\n(b) What is manure ? How does green manure differ from biofertilizers ? [3]
\n(c) What is IPM ? Give an example of bioinsecticides and bioherbicides and how do they help in pest control. [3]
\nAnswer:
\n(a) When basically dissimilar parts of different animals are modified for the same purpose it is ‘ called convergent evolution, e.g. wing of bat-modification of forelimb and wings of insect are the extension of body wall and when the same basic organ becomes adapted by specialisation to different functions, it is known as divergent evolution e.g. limbs of vertebrates.<\/p>\n
(b) Manures are the organic wastes which after partial decay is added to the soil to increase the crop productivity. It supplies all the essential mineral requirement for the crop plant.<\/p>\n
The green manure crop supplies the organic as well as inorganic components to the soil. It also provides the protective action against erosion and leaching where, as biofertilizers are micro-organisms which enrich the soil in nutrients by enhancing the availability of nutrients.<\/p>\n
(c) IPM – Integrated Pest Management.
\nBioinsecticide – Bacillus thuringiensis, the spores of soil bacteria-produce a protein which kills larvae of certain insect pests.
\nBioherbicides – Cochineal insect – Used to reduce the over growth of cacti.<\/p>\n
Question 10.
\n(a) What is mental illness ? Explain any three methods of treatment of mental illness. [4]
\n(b) What are Koch\u2019s postulates ? Why are they not applicable to viruses ? [3]
\n(c) Name the Causative agent and the main symptom of each of the following diseases : [3]
\n(i) Filariasis
\n(ii) Rabies
\n(iii) Chickenpox
\nAnswer:
\n(a) Mental illness
\n(i) It is the abnormal change in thinking, feeling, memory leading to change in behaviour and in the manner of talking. The patient may have partial or total loss of memory, self-de-structive behaviour, hallucination etc.
\nTreatements – Psychotherapy, Chemotherap, Electric Shock Treatment (ECT)<\/p>\n
(i) Psychotherapy (psychological treatment) : It can help the patient to adjust to his sur-roundings (home, place of work, society). Social therapy is aimed at rehabilitation of the victim. Re-creational activities, involvement in family life, removal of maladjustments can give relief, if not complete cure to chronic mental patients.
\n(ii) Chemotherapy : Drugs can cure psychoses fully if started early and used regularly e.g. amphetamines, barbiturates etc.
\n(iii) Electric shock treatment (ECT) : It is a crude method, used to relieve severe depression. The introduction of the psychotropic drugs has considerably reduced this method.<\/p>\n
(b) Koch\u2019s Postulates In 1876, a German microbiologist, Robert Koch discovered that a large number of microorganisms such as viruses, bacteria, fungi, protozoans, etc. cause diseases in human body. He stated that certain requirements should be fulfilled if the disease causing character of any organism is to be proved. These requirements are Koch\u2019s postulates which are given below.<\/p>\n
\n- The organisms (pathogen) must be regularly found in the body of the animal that is suffering from a disease.<\/li>\n
- The organism must be isolated that grow in pure culture on artificial media.<\/li>\n
- The same disease must be produced when the cultured organisms are injected into other healthy animals.<\/li>\n
- The same organism must be recovered from the injected animals.<\/li>\n<\/ol>\n
These postulates originally were applied for animal diseases but are equally applicable for human diseases. However, Koch s postulates are not applicable to viral diseases because they cannot be cultured on artificial media. Koch\u2019s postulates are also not applicable to the bacteria of leprosy.<\/p>\n
Disease:<\/p>\n
\n- Filariasis<\/li>\n
- Rabies<\/li>\n
- Chickenpox<\/li>\n<\/ul>\n
Causative agent:<\/p>\n
\n- Wuchereria bancrofti<\/li>\n
- rabies virus<\/li>\n
- Vpricella zoster<\/li>\n<\/ul>\n
Symptom:<\/p>\n
\n- the inflammatory thickness of the wall of lymphatic vessel.<\/li>\n
- Severe headache, high fever, severe and painful spasm of muscles<\/li>\n
- Skin eruption occurs as small red papules which grows out into pustules<\/li>\n<\/ul>\n