GK: Class 12 General Q&A · Page 156
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
Name the micro-organism which is used for the large scale production of alcohol.
Yeast, specifically the species Saccharomyces cerevisiae, is the microorganism used extensively for large-scale commercial alcohol production. This single-celled fungus carries out alcoholic fermentation, a metabolic process where it breaks down sugars (glucose, fructose, or sucrose) in the absence of oxygen, producing ethanol (alcohol) and carbon dioxide as byproducts. Breweries, distilleries, and wineries rely on controlled yeast fermentation to produce beer, wine, whiskey, vodka,
- GeneralClass 12All
What are the major groups of microorganisms?
The major groups of microorganisms include bacteria, viruses, fungi, protozoa, and algae, each with distinct characteristics, structures, and ecological roles. Bacteria are single-celled prokaryotic organisms without a defined nucleus, found virtually everywhere and playing crucial roles in nutrient cycling, digestion, and decomposition, though some cause diseases. Viruses are non-cellular infectious agents that require living host cells to reproduce, causing numerous plant, animal, and human
- GeneralClass 12All
What is the name of the microorganisms which reproduce only inside the living cells of other organisms?
Viruses are the microorganisms that can reproduce only inside the living cells of host organisms. Unlike bacteria, fungi, or protozoa, viruses are not technically considered fully "alive" because they lack cellular structure, cannot carry out metabolic processes independently, and possess no machinery for self-replication. A virus consists simply of genetic material (DNA or RNA) enclosed in a protein coat, and sometimes an outer lipid envelope. Once a virus invades a host cell, it hij
- GeneralClass 12All
Describe briefly how soil is prepared for sowing the seeds.
Soil preparation for sowing seeds involves a systematic process that begins with ploughing the field to break up compacted soil, turn over the topsoil layer, and bury crop residues and weeds. Ploughing is typically done using implements like a plough (pulled by tractors or bullocks) that cuts, lifts, and inverts soil furrows, improving soil aeration, facilitating root penetration, and bringing nutrients from deeper layers to the surface. This initial tillage operation loosens the soil structu
- GeneralClass 12All
If wheat is sown in the kharif season, what would happen? Discuss.
If wheat is sown in the kharif season, the crop would likely fail or produce extremely poor yields due to unsuitable climatic conditions that do not match wheat's biological requirements. Wheat is a Rabi crop that requires cool germination conditions (15-20°C) and moderate temperatures during vegetative growth, with optimal development occurring at temperatures between 20-25°C during grain filling. The kharif season, characterized by high temperatures (often exceeding 30-35°C), he
- GeneralClass 12All
What are weeds? Name any one weed found in a crop field.
Weeds are unwanted plants that grow alongside cultivated crops in agricultural fields, competing with them for essential resources such as nutrients, water, sunlight, and space. These undesirable plants emerge naturally from seeds already present in the soil or introduced through wind, water, animals, or contaminated inputs, and they can significantly reduce crop yields by interfering with crop growth and development. Weeds also serve as hosts for various pests and diseases that can subsequen
- GeneralClass 12All
How many crop seasons are observed in India? Name three crops cultivated during each crop season.
India observes three main crop seasons: Kharif, Rabi, and Zaid. The Kharif season extends from June-July to September-October, coinciding with the southwest monsoon, and includes crops like paddy (rice), maize, cotton, soybean, groundnut, and millets (bajra, jowar). The Rabi season runs from October-November to March-April during the winter months and includes crops such as wheat, gram (chickpea), pea, mustard, barley, and lentils. The Zaid season is a short summer season between Rabi and Kha
- GeneralClass 12All
Explain why the frequency of irrigation of crops is higher in summer season.
The frequency of irrigation is higher in summer season due to increased evaporation rates and higher water demand by crops under elevated temperatures. During summer, intense solar radiation and high atmospheric temperatures cause rapid evaporation of water from the soil surface and increased transpiration from plant leaves, leading to faster depletion of soil moisture. The rate of evapotranspiration—the combined water loss from soil evaporation and plant transpiration—can be two
- GeneralClass 12All
Match items in column-A with those in column B.
(i) Kharif crops — (e) Paddy and maize (ii) Rabi crops — (d) Wheat, gram, pea (iii) Chemical fertilizers — (b) Urea and super phosphate (iv) Organic manure — (c) Animal excreta, cow dung urine and plant waste The remaining option (a) Food for cattle does not directly match with the given items in column A as it represents a use rather than a crop category or input type.
- GeneralClass 12All
Give any four differences between manure and fertilizers.
Manure and fertilizers differ fundamentally in their origin, composition, and effects on soil and crops. First, manure is organic material derived from decomposed animal waste, plant residues, and other biological sources, while fertilizers are inorganic chemicals manufactured in factories through industrial processes. Second, manure contains relatively low concentrations of nutrients in varying proportions and releases them slowly over time, whereas fertilizers contain high concentrations of
- GeneralClass 12All
Describe the sprinkler system of irrigation. State its advantages.
The sprinkler system of irrigation is a modern method where water is sprayed over crops in the form of artificial rain through a network of pipes and rotating nozzles called sprinklers. In this system, water is pumped through pipes and distributed through sprinkler heads mounted on risers at regular intervals across the field, creating a spray pattern that simulates natural rainfall. The water breaks into small droplets and falls uniformly over the crop canopy and soil surface, ensuring even
- GeneralClass 12All
Name any three commonly used fertilizers.
Three commonly used fertilizers are urea, diammonium phosphate (DAP), and muriate of potash (MOP or potassium chloride). Urea is the most widely used nitrogenous fertilizer containing about 46% nitrogen, essential for leafy growth and overall plant development. DAP provides both nitrogen (18%) and phosphorus (46% P₂O₅), supporting root development, flowering, and fruiting. Muriate of potash supplies potassium (60% K₂O), which enhances disease resistance, water regulation, and overall plant vi
- GeneralClass 12All
What is the best time for the removal of weeds?
. The best time for removal of weeds is before they flower and produce seeds, ideally during the early growth stages of the crop. Removing weeds when they are young and before they have established deep root systems makes the process easier and more effective, preventing them from competing significantly with crop plants for resources. Early weed removal, typically within the first 3-6 weeks after sowing depending on the crop, prevents seed production that would lead to future weed pr
- GeneralClass 12All
Name one crop which can tolerate standing water (water-logging) in the field and one which cannot.
Rice (paddy) is a crop that can tolerate standing water in the field, while wheat is a crop that cannot tolerate waterlogging. Rice is specially adapted to grow in waterlogged conditions with its aerenchyma tissue that allows oxygen transport to submerged roots, making it ideal for cultivation in flooded paddy fields. This standing water also helps suppress weed growth and maintains optimal growing conditions for rice. In contrast, wheat requires well-drained soil and suffers from root damage
- GeneralClass 12All
For what purpose is a hoe used?
A hoe is used for removing weeds and loosening the soil around crop plants. This simple agricultural hand tool consists of a long handle with a flat blade attached at an angle, allowing farmers to break up soil clumps, uproot unwanted weeds, and create proper aeration in the soil. Hoeing serves multiple purposes including mixing manure or fertilizers into the topsoil, creating furrows for irrigation or sowing, and preventing soil compaction around growing plants. Regular hoeing during the cro
- GeneralClass 12All
Name the major food nutrient provided by fish.
The major food nutrient provided by fish is protein. Fish is an excellent source of high-quality, easily digestible protein that contains all essential amino acids required for human growth and development. Beyond protein, fish also provides valuable omega-3 fatty acids (particularly in oily fish), vitamins (especially vitamin D and B-complex vitamins), and minerals like iodine, selenium, and phosphorus. The protein content in fish typically ranges from 15-25% depending on the species, making
- GeneralClass 12All
What name is given to that branch of agriculture which deals with feeding, shelter, health and breeding of domestic animals?
Animal husbandry is the branch of agriculture that deals with feeding, shelter, health, and breeding of domestic animals. This scientific practice involves the systematic rearing and management of livestock such as cattle, buffalo, goats, sheep, poultry, and fish for agricultural purposes. Animal husbandry encompasses proper nutrition management, disease prevention and treatment, housing facility design, and selective breeding programs to improve livestock productivity and quality. It plays a
- GeneralClass 12All
Some grass is growing in a wheat field. What will it be known as?
The grass growing in a wheat field will be known as a weed. Weeds are unwanted plants that grow naturally along with cultivated crops and compete with them for essential resources like nutrients, water, sunlight, and space. These undesirable plants reduce crop yield and quality by depriving the main crop of vital growth requirements. Common grass-type weeds found in wheat fields include Phalaris minor (canary grass) and wild oats, which can significantly impact wheat production if no
- GeneralClass 12All
Which crop is generally grown between two cereal crops in crop rotation to restore the fertility of soil?
Leguminous crops such as pulses (gram, pea, lentils, beans) are generally grown between two cereal crops in crop rotation to restore soil fertility. These crops have a unique ability to fix atmospheric nitrogen in the soil through symbiotic bacteria called Rhizobium present in their root nodules. This biological nitrogen fixation replenishes soil nitrogen that gets depleted after growing nitrogen-demanding cereal crops, reducing the need for chemical fertilizers and maintaining long-
- GeneralClass 12All
Name the places where grains are stored on large scale.
Grains are stored on a large scale in structures called silos and granaries. Silos are tall, cylindrical structures typically made of metal or concrete that provide controlled storage conditions for bulk grains, while granaries are large warehouse-like buildings designed for grain storage. These storage facilities maintain proper temperature, humidity, and ventilation to protect grains from moisture, pests, rodents, and microbial spoilage. At the government level in India, the Food Corporatio