Explore topic-wise InterviewSolutions in Current Affairs.

Hay: Grass that has been mown and dried for use as fodder.

Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s), called aneuploidy.

Difference between aneuploidy and polyploidy

1. Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s), called aneuploidy. Failure of cytokinesis after telophase stage of cell division results in an increase in a whole set of chromosomes in an organism and,this phenomenon is known as polyploidy.

2. Polyploidy occurs due to altering set of chromosome number such as 2n, 3n, 5n, whereas aneuploidy occurs due to altering particular chromosome or part of a chromosome such as 2n + 1 (trisomic) and 2n – 1 (monosomic).

3. Aneuploidy can be seen in human as genetic disorders; for example, Tuner syndrome, Klinefelter syndrome and Down syndrome, whereas polyploidy is common in plants.

(i) Down’s Syndrome (Mongolism)

• The cause of this genetic disorder-is the presence of an additional copy of the chromosome number 21 (trisomy of 21) due to non-disjunction of chromosomes during sperm or ova formation.

• The affected individual is short statured with small round head, furrowed tongue and partially open mouth. Palm is broad with characteristic palm crease.

• Physical, psychomotor and mental development is retarded.

(ii) Klinefelter’s Syndrome

• This genetic disorder is also caused due to the presence of an additional copy of X-chromosome resulting into a karyotype of 47, XXY.

• Such an individual has overall masculine development, however, the feminine development (development of breast, i.e., Gynaecomastia) is also expressed. Such individuals are sterile male.

(iii) Turner’s Syndrome Such a disorder is caused due to the absence of one of the X chromosomes, i.e., 45 with XO. Such females are sterile as ovaries are rudimentary besides other features including lack of other secondary sexual characters.

Botulism: Clostridium botulinum is a bacterium that is widely responsible for causing food poisoning. The disease is known as Botulism.

Typhoid: Typhoid fever is an acute illness associated with fever that is most often caused by the Salmonella typhi bacteria.

Transgenic: Being an organism whose genome has been altered by the transfer of a gene or genes from another species.

Tuberculosis: It is a contagious bacterial infection that involves the lungs, but may spread to other organs.

Swine flu: Swine flu (swine influenza) is a respiratory disease caused by viruses (influenza viruses) that infect the respiratory tract of pigs and result in nasal secretions, etc.

(A) Carbon dioxide

(A) Antibiotics

We can see the cell wall cytoplasm, nucleus, chloroplast and mitochondria with \ a compound microscope.

Correct answer is: (c) Clostridium

Answer is (C) Alcohol

Biogas is a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural wastes, manure, municipal wastes, plant material, sewage, food waste, etc., Biogas is produced under anaerobic condition, when the organic materials are converted through microbiological reactions into gas and organic fertilizer. Biogas primarily consists of methane (63 percent), along with CO and hydrogen. Methane producing bacteria are called methanogens and one such common bacterium is Methanobacterium. Biogas is devoid of smell and bums with a blue flame without smoke.

The Methanogens are also present in anaerobic sludge and rumen of cattle. In rumen, these bacteria help in the breakdown of cellulose. The excreta of cattle called dung is commonly called “Gobar”. Gobar gas is generated by the anaerobic decomposition of cattle dung. It consists of methane, CO₂ with some hydrogen, nitrogen and other gases in trace amounts.

In a biogas plant, anaerobic digestion is carried out in an air tight cylindrical tank known as digester. It is made up of concrete bricks and cement or steel. Bio-wastes are collected and slurry of dung is fed into this digester. It has a side opening into which organic materials for digestion are incorporated for microbial activity. Anaerobic digestion is accomplished in three stages: solubilisation, acidogenesis and methanogenisis. The outlet is connected to a pipe to supply biogas. The slurry is drained through another outlet and is used as fertilizer. Biogas is used for cooking and lighting. The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).

Biofertilisers are formulation of living microorganisms that enrich the nutrient quality of the soil. They increase physico – chemical properties of soils such as soil structure, texture, water holding capacity, cation exchange capacity and pH by providing several nutrients and sufficient organic matter. The main sources of biofertilisers are bacteria, fungi and cyanobacteria. Rhizobium is a classical example for symbiotic nitrogen fixing bacteria. This bacterium infects the root nodules of leguminous plants and fixes atmospheric nitrogen into organic forms. Azospirillum and Azotobacter are free living bacteria that fix atmospheric nitrogen and enrich the nitrogen content of soil.

A symbiotic association between a fungus and the roots of the plants is called mycorrhiza. The fungal symbiont in these associations absorbs the phosphorus from soil and transfers to the plant. Plants having such association show other benefits such as resistance to rootbome pathogens, tolerance to salinity, drought, enhances plant growth and developments. 

For example, many members of the genus Glomus form mycorrhiza.

Cyanobacteria (or) blue green algae (BGA) are prokaryotic free-living organisms which can fix nitrogen. Oscillatoria, Nostoc, Anabaena, Tolypothrix are well known nitrogen fixing cyanobacteria. Their importance is realized in the water logged paddy fields where Cyanobacteria multiply and fix molecular nitrogen. Cyanobacteria secrete growth promoting substances like indole-3-acetic acid, indole-3-butyric acid, naphthalene acetic acid, amino acids, proteins, vitamins which promotes plant growth and production.

Biofertilisers are commonly used in organic farming methods. Organic farming is a technique, which involves cultivation of plants and rearing of animals in natural ways. This process involves the use of biological materials, avoiding synthetic substances to maintain soil fertility and ecological balance thereby minimizing pollution and wastage.

Key features of organic farming

1. Protecting soil quality using organic materials and encouraging biological activity. 

2. Indirect provision of crop nutrients using soil microorganisms.

3. Nitrogen fixation in soils using legumes. 

4. Weed and pest control based on methods like crop rotation, biological diversity, natural predators, organic manures and suitable chemical, thermal and biological interventions.

Biogas is used for cooking and lighting. The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).

Gas - Carbon dioxide 

Process - Fermentation

Saccharomyces cerevisiae commonly called brewer’s yeast is used for fermenting malted cereals and fruit juices to produce various alcoholic beverages. Wine and beer are produced without distillation, whereas whisky, brandy and rum are obtained by fermentation and distillation.

Saccharomyces cerevisiae.

Saecharum barberi, Saecharomyces cerivisial Sonalika. 

• In order to make the bread the baker’s yeast – Saccharomyces cerevisiae is added to the flour for the fermentation process.
• In commercial bakery, compressed yeast is used while in domestic settings dry, granular form of yeast is used.
• The flour prepared by using commercial yeast contains various useful contents like carbohydrates, fats, proteins, various vitamins, and minerals.
• The anaerobic fermentation also increases the nutritive content of the flour.
• Due to this, bread and other products produced with the help of yeast become nutritive.

Bacillus Calmette–Guerin (BCG) is used against Tuberculosis.

Non-infectious diseases 

E.g : 

Some cancers, high blood pressure etc.

1. What are the causes for a disease? 

2. Name the organisms that cause diseases. 

3. Name the diseases caused by virus, bacteria, fungi and protozoans. 

4. How the infectious agents spread? 

5. Name the diseases caused by air, water and physical contact. 

6. What are the symptoms of Typhoid and Jaundice? 

7. How can we prevent exposure to infectious diseases? 

8. How do we kill microbes? 

9. How to get rid of an infection in some one who has the disease? 

10. What are the treatments for any type of diseases? 

11. What are the measures taken by Public Health, Programmes to prevent diseases? 

12. What is immunization? What are antibiotics? 

13. What is the duty of everyone in the community for the effective prevention of infectious diseases?

An English physician named Edward Jenner discovered vaccine for small pox for the first time.

1. Vaccination was discovered by a British doctor called Edward Jenner in the year 1776. Since then, this method has been modified and has become most popular for making people resistant to disease. 

2. In this process, the disease causing organism are cultured in the laboratory and are collected. They are killed by heat treatment. 

3. The dead micro-organisms are made into a suspension and injected into humans. The body reacts to these dead microorganisms as if they are alive and are produces antibodies. 

4. Next time when the same disease producing micro-organisms enter the body, these antibodies will react and kill them. 

5. Thus the person is not affected by the disease, even if he is exposed to the disease causing microorganisms. Vaccination also prevents the spread of epidemics. 

6. At present, vaccines are available for various diseases-Cholera, typhoid, diphtheria, whooping cough, polio, tuberculosis etc. Some of the vaccines if taken once, the immunity persists for life time, while in some cases the immunity will lasts only for limited amount of time.

Prevention of Small Pox:

1. Isolation of the infected person. 

2. Surrounding should be kept clean and hygeinic. 

3. Clothes of the infected person must be washed in hot water and dried in the Sun. 

4. They should not be used by others. 

5. Small Pox can be prevented by taking vaccine against it. 

6. But in 1776 Edward Jenner discovered a vaccine for small pox.Now it is wiped out from our country.

When sweety suffered from chicken-pox, antibodies were prepared by her body in response to the action of chicken pox virus. This is an example of active immunity in which body prepares antibodies against the disease causing microbe and store it for a very long period. When the person encounters the same disease again, the pre-formed antibodies present in the blood come for rescue. Hence, Sweety will not encounter chicken pox again.

The boy when encounters a pathogen for the first time, his body produces antibodies that results in the memory of the first encounter, to protect the body in future.

(a) S. Satyamurty

1. Primary Lymphoid organs: Bone marrow and thymus.

2. Secondary Lymphoid organs: Spleen, lymph nodes, Peyer’s patches (small intestine) and mucosal associated lymphoid tissues (MALT).

The first infection of chicken pox produces a primary response and antibodies are generated against chicken pox virus, subsequent encounter with the same virus elicits a highly intensified secondary response , due to the memory cells formed during the first encounter. This kind of an immunity is active immunity.

Correct Answer is: (b) 1926

i. Primary lymphoid organs 

• The organs where lymphocytes originate and mature to become antigensensitive, e.g., bone marrow and thymus, are called primary lymphoid organs. 

a. Bone marrow 

• It is the primary lymphoid organ where all blood cells including lymphocytes originate. 

• Bone marrow provides the micro-environment for the development and maturation of B-lymphocytes. 

b. Thymus 

• Thymus is a lobed organ located near the heart and beneath the breastbone. 

• It is quite large at the time of birth but reduces with age. 

• It provides the micro-environment for the development and maturation of T-lymphocytes. 

ii. Secondary lymphoid organs 

• The organs where lymphocytes interact with the antigen and proliferate to become effector cells, e.g., spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix are called secondary lymphoid organs. 

a. Spleen 

• It is a large bean-shaped organ and contains lymphocytes and phagocytes. 

• It acts as a filter of the blood by trapping blood-borne microorganisms. 

• It has a large reservoir of erythrocytes. 

b. Lymph nodes 

• These are small solid structures present at different points along the lymphatic system. 

• They trap the microorganisms or other antigens that enter the lymph and tissue fluid. 

• Antigens trapped in the lymph nodes activate the lymphocytes and produce an immune response. 

c. Mucosal associated lymphoid tissue (MALT) 

• It is formed of masses of lymphoid tissue lining the mucosa of respiratory, digestive and urinogenital tracts. 

• 50 per cent of the lymphoid tissue in human body is formed by MALT.

(A) four

Genotype \(\rightarrow\) AaBbcc

No. of gametes produced = 2ⁿ (n = no. of heterozygous alleles)

Here, n = 2 (Aa, Bb)

∴ No. of gametes produced = 2² = 4

(ABc, Abc, aBc, abc)

(A) One

In AABBCC, there is no heterozygous allele. So, only one type of gamete can be formed.

(B) 8

The eight gametes produced will be – ABC, ABc, AbC, Abc, aBC, aBc, abC, abc

(b) Vaniyambadi

(a) Both A and R are correct R explains A.

(c) Simon commission

(A) RY, Ry, rY, ry

RrYy is a dihybrid, so four types of gametes are formed - RY, Ry, rY, ry

(a) The South Indian Liberal Federation was formed to promote the interests of non-Brahmins.

(b) The Non-Brahmin Manifesto had objectives such as reservation of jobs for non-Brahmins in government service and seats in representative bodies. It opposed the Home Rule Movement and criticised Congress as a party of Brahmins.

(c) EVR joined the non-Brahmin movement because he felt the Congress was promoting the interests of Brahmins alone.

(d) A massive campaign was led by EVR against the introduction of Hindi as a compulsory subject in schools. The anti-Hindi agitation was popular because Hindi was considered a form of Aryan and North Indian imposition. EVR organized an anti-Hindi conference. More than ‘ 1200 protesters were arrested at a rally. The subject was later removed after protests.

(b) Namakkal V Ramalingam

(a) (i) and (ii) are correct

(b) Quit India Movement

(c) (ii) is correc

(d) Both A and R are correct and R is the correct explanation of A.

A. (iv) 

B. (v)

C. (ii)

D. (iii) 

E. (i)

(b) A is correct but R is wrong.

i. The spectra is not continuous and comprises of a series of lines corresponding to different frequencies.

ii. Paschen series falls in the infrared region of electromagnetic radiation.

iii. Balmer series falls partly in the visible region of electromagnetic radiation.

The magnetic moment of each half bar magnet is \(\frac{M}{2}\) but oppositely directed, so net magnetic moment of combination = \(\frac{M}{2}\) -  \(\frac{M}{2}\) = (zero).