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Biology And Human Welfare

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Biology and Human Welfare PDF Notes, Important Questions and Formulas


Biology and Human Welfare



(1)  Disease: - Any change from the normal state that causes discomfort or disability or impairs the health is called as disease.

(2)  Health: - Health is a state of complete physical, mental and social well-being, and not merely an absence of disease or infirmity (W.H.O - 1948)

(3)  Prophylaxis or preventive measures: Preventive measure for a disease is called prophylaxis.

(4)  Epidemiology: - The study of causes and spread of disease is called Epidemiology. (epi = among, demos = Human, logy = study)

(5)  Etiology: - Study of the cause of disease is called Etiology.

(6)  Incubation period: - Time interval between the entry of pathogen and appearance of symptoms is called incubation period. Window period: - Period between infection to the time when it can be laboratrically detected.

(7)  Chemotherapy: Treatment with chemicals (Medicine)

(A)  Antibiotics: Substances which are secreted by microorganism that inhibit the growth or destroy the other microorganism are called antibiotics. This term was given by Walksman (Streptomycin–first bacterial antibiotic obtained from bacteria - Streptomycin griseus).

Example - Bacteriostatic-Tetracycllin, Chloramphenicol, Bacteriolytic or Bacteriocidal- Streptomycin, Ciprofloxacin, Ampicillin.

(B)  Analgesics: Substance that relieves pain. Example - Opioid analgesics - Morphine, Codeine, Diclofenac sodium, Nemuslide

(C)  Antipyretics (Antifebrile): (Pyrexia - Fever) Substance that reduces temperature or fever of body. Example - Aspirin (Acetyl salicylic acid) - (It produces gastric ulcer so not extensively recommended as an analgesic), Ibuprofen, Paracetamol, Nemuslide.

(D) Antihistaminic drug: These drugs give relief from allergies by neutralizing histamines that is released from the ruptured mast cell. E.g. cetirizine

(E)  Tranquillisers and Hypnotics and Sedative drug:

  1. Tranquilliser drug: A drug that act to reduce mental tension and anxiety without interfering with normal mental activity. 
  2. Sedative drug: A drug that calms the subject without inducing sleep but if used in high dose can cause sleep.
  3.  Hypnotic drug: A drug that induces sleep.

(F) Antiseptic and Disinfectant: Agent that inhibit or kill microbes on contact. Conventionally agents used on living surfaces are called antiseptics while those used for inanimate objects are called disinfectants. Disinfection: In this process, kill only vegetative form of bacteria. Sterilisation: In this process, kill all form of pathogens including spores.

  1. 2.     IMMUNE SYSTEM

System of body which protects the body from disease is called immune system. ('Immune = Exempt or Freedom)

Some terms related to immunity:

(1)  Immunity: Resistance of the body against a pathogen or disease.

(2)  Antigen or Agglutinogen: Proteinous substance which stimulates the production of antibodies.



A common example is the production of curd from milk. Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculum or starter contain millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality by increasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease causing microbes.

The dough, which is used for making foods such as dosa and idli is also fermented by bacteria. The puffedup appearance of dough is due to the production of CO2 gas. Similarly the dough, which is used for making bread, is fermented using baker's yeast (Saccharomyces cerevisiae). A number of traditional drinks (e.g. ''Todi' prepared from sap of palms) and foods are also made by fermentation by the microbes. Microbes are also used to ferment fish, soyabean and bamboo shoots to make foods. Cheese, is one of the oldest food items in which microbes were used. Different varieties of cheese are known by their characteristic textur flavour and taste, the specificity coming from the microbes used.

For example, the large holes in 'Swiss cheese' are due to production of a large amount of CO2 by a bacterium named Propionibacterium sharmanii. The 'Roquefort cheese' are ripened by growing a specific fungi on them, which gives them a particular flavour.



A.     Alcoholic (Fermented) Beverage Louis Pasteur showed in the middle of nineteenth century that beer and butter milk are product of fermentation brought about by "yeast". It is a microscopic single celled organism – Saccharomyces cerevisiae. Presently however yeast product for human and animal consumption are produced on commercial scale. "Alcohol was the first product of ancient biotechnology"

There are basically two types of yeasts (i) Baker's yeast (ii) Alcohol yeast or Brewer's yeast Baker's yeast generally utilize during the preparation of food materials to increase the taste of food, flavour in food and nutrients in food. It is also utilized as "leavening agent". By the incomplete degradation of complex organic compounds [sucrose] by yeast fermentation, alcohol is formed.

Industrial utilization of biotechnology involve three steps –

  1. Laboratory scale process
  2. Pilot plant scale
  3. Manufacturing unit

The development from laboratory scale to manufacturing unit is "Scaling up to industrial production"

(i)   Laboratory Scale –

In this process for the production of desirable product, proper micro-organism searched and then suitable strain is selected and multiplied. Proper medium also find out on which selected strain, produce best and more amount of product. Many number of experiments performed in lab for the analysis and selection of strains and medium. All the equipment are utilized in lab i.e., glass apparatus. All the parameters of the process worked out and precaution are also not down for the smooth running of process such as – proper sterlization of nutrient and microbesstrain, required - pH, suitable aerator, disposal of CO2 if evovled, temperature, by product or product inhibition or stimulation, time of optimum production, separation of product and its purification etc. Ultimately, the laboratory scale process finalized and transfer at pilot plant scale.

(ii)Pilot plant Scale –

It is the intermediate stage where working of laboratory scale process is tested. At this stage cost and quality of product thoroughly checked. Glass apparatus are replaced by stainless steel equipment containers is called "bio reactor". To produce in large quantities, the development of bioreactors. Where large volumes (100-1000 litres) of culture can be processed, was required. Thus, bioreactors can be thought of as vessels in which raw materials are biologically converted into specific products, individual enzymes, etc., useing microbial plant, animal or human cells. A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions (temperature, pH, substrate, salts, vitamins, oxygen).

The most commonly used bioreacters are of stirring type A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer faciliates even mixing and oxygen availability throughout the bioreactor.

Alternatively air can be bubbled through the reactor. The bioreactor has an agitator system, an oxygen delivery system and a foam control system, a temperature control system, pH control system and sampling parts so that small volumes of the culture can be withdrawn periodically.




ANIMAL HUSBANDRY' is Science of rearing, improvement and caring of domesticated animals.

  • Livestock Cattle in particular are very useful in Indian agriculture.
  • Cow, Buffaloes, goats & Sheep are domesticated for milk.
  • Many animals as horse cattles, mules, asses, camels, elephants & randiers are used for transport.
  • Sheep, rabbit and silkworms provide wool, fur & silk respectively.
  • The first animal to be domesticated was dog followed goat.
  • Huskies are thick coated dogs used by eskimos to draw their sledges.


Breeding of animals is an important aspect of animal husbandry. Animal breeding aims at increasing the yield of animals and improving the desirable qualities of the produce. For what kind of characters would we breed animals? Would the selection of characters differ with the choice of animals?

What do we understand by the term 'breed'? A group of animals related by descent and similar in most characters like general appearance, features, size, configuration, etc., are said to belong to a breed. Find out the names of some common breeds of cattle and poultry in the farms of your area.

When breeding is between animals of the same breed it is called inbreeding , while crosses between different breeds are called outbreeding.

(A)  Inbreeding : Inbreeding refers to the mating of more closely related individuals within the same breed for 4-6 generations. The breeding strategy is as follows - superior males and superior females of the same breed are identified and mated in pairs. The progeny obtained from such matings are evaluated and superior males and females among them are identified for further mating. A superior female, in the case of cattle, is the cow or buffalo that produces more milk per lactation.

On the other hand, a superior male is the bull, which gives rise to superior progeny as compared to those of other males.

Try to recollect the homozygous purelines developed by Mendel. A similar strategy is used for developing purelines in cattle as was used in case of peas. Inbreeding increases homozygosity. Thus inbreeding is necessary if we want to evolve a pureline in any animal Inbreeding exposes harmful recessive genes that are eliminated by selection. It also helps in accumulation of superior genes and elimination of less desirable genes. Therefore, this approach, where there is selection at each step, increases the productivity of inbreed population. However, continued inbreeding, especially close inbreeding and usually reduces fertility and even productivity. This is called inbreeding depression. Whenever this becomes a problem, selected animals of the breeding population should be mated with unrelated superior animals of the same breed. This usually helps restore fertility and yield.

(B)  Out-breeding: Out-breeding is the breeding of the unrelated animals, which may be between individuals of the same breed (but having no common ancestors), or between different breeds (cross·breeding) or different species (inter-specific hybridisation).

(i)   Out-crossing: This is the practice of mating of animals within the same breed, but having no common ancestors on either side of their pedigree up to 4-6 generations. The offspring of such a mating is known as an out-cross. It is the best breeding method for animals that are below average in productivity in milk production, growth rate in beef cattle, etc. A single outcross often helps to overcome inbreeding depression.

(ii)Cross-breeding: In this method, superior males of one breed are mated with superior females of another breed. Cross-breeding allows the desirable qualities of two different breeds to be combined. The progeny hybrid animals may themselves be used for commercial production. Alternatively they may be subjected to some form of inbreeding and selection to develop new stable breeds that may be superior to the existing breeds. Many new animal breeds have been developed by this approach. Hisardale is a new breed of sheep developed in Punjab by crossing Bikaneri ewes and Marino rams.

(iii)    Interspecific hybridisation: In this method, male and female animals of two different species are mated. In some case -, the progeny may combine desirable features of both the parents, and may be of considerable economic value, e.g., Mules are sturdier and hardier than their parental species, that are well suited for hard work in difficult terrains like mountainous regions.

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