Revision: Enhancement of Food Production Biology HSC Science (General) 12th Standard Board Exam Maharashtra State Board

The hydrostatic pressure which balances and prevents the osmotic inflow of water into concentrated solution is called osmotic pressure.

Osmotic pressure may be defined as the external pressure which should be applied to the solution in order to stop the phenomenon of osmosis, i.e., to stop the flow of solvent into the solution when the two are separated by a semipermeable membrane.

A group of cells having the same origin, same structure and same function is called ‘tissue’.

'Ex vivo growth of cells or tissues in an aseptic and nutrient-rich medium’ is called tissue culture.

or

Tissue culture is the technique of growing plant cells, tissues or organs under controlled laboratory conditions for crop improvement.

Single Cell Protein is the microbial biomass obtained from bacteria, yeasts, fungi or algae and used as a source of protein for human food or animal feed.

Biofortification is the breeding of crop plants to increase their content of vitamins, minerals, proteins or healthy fats in order to improve human nutrition and public health.

It is a livestock breeding and growing practice in agriculture.

The rearing of honey bee to obtain honey and other commercially important products is known as apiculture or bee‑keeping.

Apiculture is the rearing of honey bees for honey. It is called Beekeeping.

Breeding between a superior male of one breed with a superior female of another breed is known as cross-breeding.

Pisciculture or Fish culture is the process of breeding and rearing fishes in ponds, reservoirs (dams), lakes, rivers, and paddy fields.

Pisciculture (fishery) is the practice of breeding, rearing and harvesting fish in natural or artificial water bodies for food and other economic uses.

Zymology is an applied science which deals with the biochemical process of fermentation and its practical uses.

Antibiotics are chemical substances produced by microorganisms which can kill or retard the growth of other disease causing microbes even in low concentration. Antibiotic means “against life”.

"Superbug" is a term used to describe strains of bacteria that are resistant to the majority of antibiotics commonly used today.

Bioherbicides are living creatures such as microbes, fungi, insects, or other pathogens that are employed to restrict the population of undesired plants in agricultural fields, ponds, lakes, and so on.

The production of genetically identical plants from a single parent plant is called clonal propagation.

The branch of applied zoology that deals with the rearing of silkworms for the production of silk is called sericulture.

The practice of rearing lac insects for the commercial production of lac is called lac culture.

The in-vitro technique of producing a large number of plants from a small piece of plant tissue under sterile conditions is called micropropagation.

The improvement or purposeful manipulation of heredity of crop plants for the production of new and superior varieties is called plant breeding.

• Food Defined: Food is any organic, energy-rich, non-poisonous, edible, and nourishing substance (solid or liquid) that, when swallowed, digested, and assimilated, keeps the body healthy.
• Food Synthesis: Green plants synthesise their own food via photosynthesis. Animals and humans cannot do so and are directly dependent on plants.
• Need for Improvement: Rapid increase in world population and famines have created a shortage of food, making it necessary to improve food production both quantitatively and qualitatively.
• Solution: Plant breeding and animal breeding are the two main approaches to increasing food production and meeting growing demands.

• Meaning — Plant breeding is the purposeful manipulation of the heredity of crops to produce new superior varieties. It is an applied branch of botany using genetics, taxonomy, physiology & biotechnology.
• Objectives — Increase crop yield, improve quality, resistance to pathogens & pests, tolerance to environmental stress, and shorter life cycle span.
• Methods — Introduction, Selection, Hybridisation, Mutation breeding, Polyploidy breeding, Tissue culture, rDNA technology, SCP, Molecular plant breeding.
• Green Revolution — Result of scientific breakthroughs using superior seeds, pesticides, fertilisers, modern machinery & irrigation → developed high-yielding disease-resistant varieties of wheat, rice, maize.
• Dr Norman Borlaug — American biologist, called "Father of the Green Revolution". Won Nobel Prize (1970) for saving millions from famine in India, Mexico & Middle East.
• Dr. M. S. Swaminathan — Called "Father of Green Revolution in India". Pioneer in mutation breeding in India. Developed wheat varieties — Sonora, NP 165, and Sharbati.

• 4 Types — Intravarietal (same variety), Intervarietal (same species), Interspecific (same genus), Intergeneric (same family).
• Step 1 — Collect variability via in situ and ex situ conservation.
• Step 2 — Evaluate and select the best parent plants.
• Step 3 — Cross-hybridise the selected parents.
• Step 4 — Select and test superior recombinants.
• Step 5 — Test, release, and commercialise new cultivars.
• Green Revolution — Hybridisation + modern machinery + pesticides/fertilisers + multiple cropping → increased food production.

1. Meaning — Inducing gene changes using mutagens to create new traits not found in the parent plant.

2. Mutagen Types:

• Natural — UV rays, X-rays, high temp, high CO₂
• Chemical — EMS, Nitrous acid, Colchicine, Mustard gas

3. Mutated Varieties (Crop → Variety → Trait):

• Rice → Jagannath → Biotic stress resistance
• Wheat → NP 836 → Rust resistance
• Cotton → Indore-2 → Bollworm resistance
• Cabbage → Regina-II → Bacterial rot resistance

3. Pest-Resistant Varieties (Crop → Variety → Pest):

• Brassica → Pusa Gaurav → Aphids
• Flat bean → Pusa sem 2 & 3 → Jassids, Aphids, Fruit borer
• Okra → Pusa Sawani, Pusa A-4 → Shoot & fruit borer

4. Pest Resistance develops due to morphological, biochemical, or physiological characteristics of the plant.

• Principle — Based on Totipotency — the ability of a single plant cell to grow, divide, and develop into a whole new plant.
• Explant — The part of the plant used in tissue culture (e.g., leaf, stem, root piece).
• Medium — Contains minerals, carbohydrates, proteins, fats, water, growth hormones, vitamins, and agar. MS medium is commonly used.
• Conditions — Aseptic, Temp: 18–20°C, pH: 5–5.8, with aeration for suspension culture.
• Steps in Order — Clean glassware → Prepare nutrient medium → Prepare explant → Inoculate in culture flask → Incubate (callus forms) → Subculture → Organogenesis → Hardening → Transfer to field.
• Types Based on Explant — Cell culture, Organ culture, Embryo culture.
• Types Based on In Vitro Growth — Callus culture uses a solid medium to form undifferentiated cells (callus) that can become organs/plantlets. Suspension culture uses a liquid medium constantly agitated by a shaker.

• Meaning — SCP is a crude or refined edible protein extracted from pure microbial cultures or dead/dried cell biomass. Its importance was first realised during World War I.
• Microorganisms Used — Fungi: Aspergillus niger, Trichoderma viride. Yeast: S. cerevisiae, Candida utilis. Algae: Spirulina, Chlorella. Bacteria: Methylophilus methylotrophus, Bacillus megasterium.
• Substrates Used — Microbes are grown on cheap/waste materials like sawdust, corn cobs, sugarcane molasses, agricultural waste, and even human & animal wastes.
• Nutritional Value — SCP contains 43–85% protein, vitamins (esp. Vitamin B complex), minerals, amino acids & fats. Used as a supplement in human and animal feed.
• Advantages — Fast multiplication of microbes → large biomass quickly. Can be genetically modified | Reduces pollution by using waste as substrate. Solves protein malnutrition.

• Meaning — Biofortification is the method of breeding crops for higher levels of vitamins, minerals and fats to improve nutritive value and overcome malnutrition.
• Methods — Achieved through conventional selective breeding or r-DNA technology. Nutrients can also be supplemented from outside.
• Objectives — Improving protein content & quality, oil content & quality, vitamin content, and micronutrient content & quality.
• Examples — Maize → 2x lysine & tryptophan, Wheat Atlas 66 → high protein, Rice → 5x more iron, Carrot & Spinach → more Vitamin A & minerals.
• IARI Contribution — Vitamin C-enriched bitter gourd and tomato were developed by IARI (Indian Agricultural Research Institute).

• Meaning — Animal husbandry is an agricultural practice of breeding and raising livestock (cows, buffaloes, pigs, sheep, camels, goats, etc.). It is both a science and an art.
• Scope — Includes poultry farming, fish farming, beekeeping, sericulture, and lac culture. Animals provide products like milk, eggs, meat, wool, honey, and silk.
• India's Status — India & China have 70% of the world's livestock but produce only 25% of the world's farm output → need for a professional & scientific approach.
• Farm Management — Starts with selecting high-yielding breeds, proper nutrition, clean environment, health maintenance, veterinary supervision & vaccination.
• Aim — Improve quality & productivity using industrial principles of production, processing and marketing with new technologies.

• Meaning — Breeding & raising livestock to increase yield and improve desirable qualities (milk, meat, eggs).
• Inbreeding — Closely related individuals bred for 4–6 generations → increases homozygosity, eliminates harmful genes. Demerit: reduces fertility.
• Outbreeding — Unrelated animals, no common ancestor for 4–6 generations → removes inbreeding depression.
• Types of Outbreeding — Outcrossing (same breed), Crossbreeding (different breeds), Interspecific hybridisation (different species).
• Examples — Hisardale sheep = Bikaneri ewe × Marino ram | Mule = Horse × Donkey.
• Artificial Insemination (AI) — Semen from a superior male → frozen/preserved → injected into the female's genital tract.
• MOET — FSH given to cow → superovulation (6–8 eggs) → blastocysts (8–32 cell stage) transferred to surrogate mothers.

• Meaning — Dairying is the management of animals for milk and milk products for human consumption. It deals with increasing yield and improving quality of milk.
• Key Factor — Milk yield primarily depends on the quality of breeds — high-yielding potential combined with disease resistance.
• Breeds — Indian cow breeds: Sahiwal, Sindhi, Gir | Exotic breeds: Jersey, Brown Swiss, Holstein | Buffalo breeds: Jaffarabadi, Murrah, Nagpuri, Nili, Mehsana, Surati.
• Importance of Cattle — Provide milk, hides, horns, hooves, blood, fat. Bullocks used for ploughing, harrowing, threshing & transporting produce.
• By-products — Cattle dung used as fuel, biogas generation & manure. Livestock plays a significant role in Indian agriculture.

• Meaning — Poultry includes domesticated birds (chicken, duck, turkey, fowl) raised for eggs and meat. Allied professions include feed, marketing, pharmaceuticals & equipment.
• Breeds by Origin — American: Plymouth Rock, New Hampshire, Rhode Island Red, Asiatic: Brahma, Cochin, Langshan, Mediterranean: Leghorn, Minorca, English: Australorp, Indian: Chittagong, Aseel, Kadaknath.
• Layers vs Broilers — Leghorn = best layer (eggs). Plymouth Rock, Rhode Island Red, Aseel, Brahma, Kadaknath = preferred broilers (meat).
• Farm Management — Requires disease-free breed, proper feed & water, hygiene, vaccination, ventilation, lighting, sanitation & culling.
• Poultry Diseases — Viral: Ranikhet, Bird flu, Bacterial: Pullorum, Cholera, TB, CRD, Fungal: Aspergillosis, Favus, Parasitic: Lice, Roundworm, Protozoan: Coccidiosis.

• Meaning — Artificial rearing of honey bees to obtain honey, wax, pollen, bee venom, propolis & royal jelly. Ancient cottage industry.
• 4 Species in India — Apis dorsata (rock bee), Apis florea (little bee), Apis mellifera (European), Apis indica (Indian). Mellifera & Indica = domesticated species.
• Requirements — Areas with shrubs, orchards & crops. Equipment: hive boxes, smoker, bee veil, gloves, uncapping knife, queen excluder.
• Management — Periodic inspection of cleanliness, queen activity, brood condition & water supply is necessary.
• Importance — Honey = nutritious + medicinal. Bees pollinate sunflowers, mustard, apples, mangoes, and citrus → increases crop productivity.

• Meaning — Branch of applied biology dealing with catching, processing, farming & marketing of fish, prawns, lobsters, oysters, mussels, crabs.
• Three Divisions — Inland (fresh water), Marine (sea water, 7500 km coastline), Estuarine (river meets sea, e.g., Sundarbans).
• Common Fish — Inland: Rohu, Catla, Mrigala | Marine: Bombay duck, Sardine, Mackerel, Pomfret.
• Fish Culture — Monoculture (1 species) or Polyculture (many species). Preservation: chilling, freezing, salting, canning, drying.
• By-products — Fish oil, fish meal, fertilisers, fish glue, isinglass → used in paints, soaps, medicines. Provides jobs & self-employment.

• Meaning — A branch of applied zoology dealing with the rearing of silkworms and the production of silk; it needs less investment and a small space.
• Types of Silk — Mulberry silk (best) → Bombyx mori; Tussar & Eri silk → inferior quality.
• Quality Factor — Quality & quantity of silk depend on the quality of mulberry leaves fed to larvae.
• Enemies — Larvae attacked by protozoans, viruses, fungi + predators like ants, crows, birds → cages must be well-managed.
• Importance — One of India's oldest industries; can be done by disabled, elderly & handicapped persons too.

• Producer — Lac is produced by the insect Trachardia lacca; resin is secreted by the dermal glands of the female insect.
• Formation — Insect feeds on twigs of ber, peepal, palas, kusum, babool → secretes pink resin → hardens in air = Lac.
• Composition — Resin + sugar + water + minerals + alkaline substances.
• Shellac — Pure form of lac obtained by washing and filtering natural (contaminated) lac.
• Importance — India produces 85% of the world's lac. Used in bangles, toys, woodwork, inks, and mirrors.

• Fermentation — Air-borne bacteria, Leuconostoc and Streptococcus, are involved in fermentation. CO₂ produced during fermentation causes dough/batter to puff up (e.g., Dosa, Idli, Dhokla).
• Curd — Formed by Lactobacillus acidophilus, which converts milk into curd by producing lactic acid.
• Yoghurt — Produced by Streptococcus thermophilus and Lactobacillus bulgaricus together.
• Cheese Types & Their Microbes — Regular cheese = lactic acid bacteria; Roquefort = Penicillium roquefortii; Camembert = Penicillium camembertii; Swiss cheese = Propionibacterium shermanii.
• Microbes as Food (SCP) — Microbes like mushrooms and truffles serve directly as food. SCP (Single Cell Protein) is also obtained from microbes as a protein-rich food source.
• Role in Flavour & Texture — Microbes via fermentation are responsible for the unique flavour and texture of food items like cheese, yoghurt, and fermented foods.

• Bio-active Compounds — Streptokinase (Streptococcus) = clot buster; Statins (Monascus purpureus) = lowers blood cholesterol.
• Antibiotics — Penicillin (Penicillium chrysogenum), Streptomycin (S. griseus), Erythromycin (S. erythreus), Oxytetracycline (S. aurifaciens), Bacitracin (Bacillus licheniformis).
• Alcoholic Beverages — Yeast (Saccharomyces cerevisiae) ferments cereals/fruit juices. Distilled = Whisky, Brandy, Rum; Non-distilled = Wine, Beer. Fenny = Goa's cashew wine.
• Organic Acids — Citric & Gluconic acid (Aspergillus niger), Acetic acid/vinegar (Acetobacter aceti), Fumaric acid (Rhizopus arrhizus).
• Vitamins — B₂ (Neurospora gossypii), B₁₂ (Pseudomonas denitrificans), Vitamin C (Aspergillus niger).
• Industrial Enzymes — Invertase (S. cerevisiae), Lipase (Candida lipolytica), Cellulase (Trichoderma konigii), Pectinase (Aspergillus niger).
• Gibberellins — Isolated from fungus Gibberella fujikuroi; ~15 types; used for parthenocarpy, seed dormancy breaking, flowering induction & enlarging grape fruits.

• Sewage = 99.5–99.9% water + 0.1–0.5% organic/inorganic matter + microbes (bacteria, viruses, fungi, algae, etc.)
• Preliminary Treatment — Bar screens remove large solids; Grit Chamber removes sand & stones.
• Primary Treatment — Sedimentation tank settles suspended solids; reduces coliform bacteria. Removes ~50–70% solids.
• Secondary Treatment — Aerobic bacteria decompose organic matter in aeration tanks; lowers BOD by 70–80%.
• Tertiary Treatment — Anaerobic bacteria digest sludge in sludge digesters; disinfection improves water quality.
• Chlorination — Kills remaining pathogenic bacteria before water release.
• Disposal — Treated water → natural water bodies; digested sludge → proper disposal/manure.

• Meaning — Biogas is a renewable energy source obtained through microbial fermentation. Key microbes: Archaebacteria and Bacillus.
• Composition — Mixture of CH₄, CO₂, H₂S, H₂, and N₂. Methane is the main combustible gas.
• Substrate & Plant — Cattle dung is the common raw material. Plant has Digester and Gas Holder. Developed by KVIC and IARI in India.
• Stage I – Solubilisation — Hydrolytic bacteria break down proteins, fats, and cellulose into simpler soluble compounds.
• Stage II – Acidogenesis — Fermentative bacteria convert monomers into organic acids (e.g., acetic acid), H₂ and CO₂.
• Stage III – Methanogenesis — Methanosarcina, Methanobacterium convert acetate + H₂ + CO₂ into methane (biogas).

• Meaning — Biocontrol agents are microbes that control pests by causing disease, competing with, or killing them, reducing dependence on chemical pesticides.
• Biopesticides — Safer, eco-friendly alternative to chemical pesticides. Key agents: Bacillus thuringiensis (Bt) → caterpillars, beetles; Beauveria bassiana → aphids, mites, white flies; Nosema locustae (protozoa) → grasshoppers, crickets; NPV & Granulovirus → gypsy moths, ants, wasps.
• Bacillus thuringiensis (Bt) — Dried spores mixed with water and sprayed on plants to kill butterfly caterpillars. Most widely used bacterial biocontrol agent.
• Trichoderma — A fungus that acts as a biocontrol agent specifically against soil-borne fungal plant pathogens.
• Microbial Herbicides — Phytophthora palmivora → milkweed; Alternaria crassa → water hyacinth; Fusarium spp. → most weeds; Pseudomonas, Xanthomonas, Agrobacterium → several weeds.
• Insects as Herbicides — Tyria moth controls Senecio jacobeae weed; Cactoblastis cactorum controls cacti weeds.

• Biofertilizers are living micro-organisms that improve soil fertility by increasing the availability of nutrients to plants.
• They are eco-friendly alternatives to chemical fertilizers, which degrade soil quality and reduce microbial life.
• Nitrogen-fixing microbes such as Rhizobium, Azotobacter, Azospirillum, and Frankia convert atmospheric nitrogen into usable forms.
• Legume–Rhizobium symbiosis forms root nodules that fix large amounts of nitrogen and enrich the soil for subsequent crops.
• Azolla–Anabaena symbiosis and cyanobacteria are widely used in paddy fields and significantly increase rice yield.
• Mycorrhiza (fungus–root association) enhances absorption of phosphorus and other minerals and protects plants from pathogens.
• Phosphate-solubilizing bacteria and fungi convert insoluble phosphates into forms available to plants.
• Biofertilizers improve crop yield, reduce fertilizer requirement, and help in sustainable agriculture and soil conservation.

• Animal Breeding
  Animal breeding is the scientific practice aimed at improving desirable traits and increasing the yield of animals and their products like milk, meat, and eggs.
• Breed
  A breed is a group of animals with common ancestry and similar characters such as size, appearance, and productivity.
• Inbreeding
  Inbreeding is the mating of closely related individuals for 4–6 generations, which increases homozygosity and helps in producing pure lines, but may reduce fertility.
• Outbreeding
  Outbreeding involves breeding of unrelated animals, including crossbreeding and interspecific hybridization, to remove inbreeding depression and improve performance.
• Modern Breeding Techniques
  Techniques like artificial insemination and MOET (Multiple Ovulation Embryo Transfer) are used to rapidly increase herd size and obtain high-yielding superior animals.

1. Poultry Farming
   Poultry farming involves the rearing of domesticated birds such as chicken, ducks, turkey, and fowls for the production of eggs and meat.
2. Requirements of Poultry Management
   Proper breed selection, housing, feed, water, hygiene, and disease control are essential for efficient poultry farm management.
3. Types of Poultry Breeds and Uses
   Leghorn is the best egg-laying (layer) breed, while Plymouth Rock, Rhode Island Red, Aseel, Brahma, and Kadaknath are preferred as broilers (meat birds).
4. Poultry Diseases
   Common poultry diseases include viral (Ranikhet, bird flu), bacterial (cholera, typhoid), fungal (aspergillosis), parasitic, and protozoan (coccidiosis) diseases.

• Sewage is liquid waste containing human excreta, organic matter, chemicals, and pathogenic microorganisms.
• Microorganisms in Sewage:
  Sewage contains bacteria, viruses, protozoa, fungi, algae, and nematodes, including disease-causing microbes.
• Preliminary Treatment:
  Large floating and heavy solid particles are removed by screening and grit chambers.
• Primary Treatment:
  Suspended solids settle in sedimentation tanks forming primary sludge, reducing organic matter and microbes.
• Secondary Treatment:
  Aerobic bacteria form flocs that degrade organic matter and significantly reduce BOD.
• Tertiary Treatment:
  Anaerobic digestion produces biogas, and treated effluent is disinfected and released or reused.