DEFINITIONS : BIOLOGY

1. LIFE PROCESSES: The processes occurring in the body of living organisms so as to maintain it are called Life Processes.


2. FOOD: A useful source of both energy and structural material to the body of an organism for growth and maintenance is called Food.


3. NUTRITION: The process of providing nutrients to the body from outside sources consumed as food is called Nutrition.


4. RESPIRATION: The process of acquiring oxygen from an external source and using it for the process of breakdown of food material for cellular needs is called Respiration.


5. BREATHING: The mechanical process of inhalation of oxygen-rich air from the environment and exhalation of oxygen-deficient(deoxygenated) air from the body alternatively is called Breathing.


6. EXCRETION: The process of removal from the body of waste by-products generated during various metabolic processes is called Excretion.


7. AUTOTROPHS: Those organisms which can prepare their own food from inorganic materials obtained from the nature are called Autotrophs.


8. HETEROTROPHS: Those organisms which cannot prepare their own food but obtain it from other living organisms are called Heterotrophs.


9. ENZYMES: Enzymes are biochemical catalysts which help in breaking down of complex food molecules in to simpler ones.


10. PHOTOSYNTHESIS: The process used by autotrophs in which they prepare complex organic molecules from simple inorganic molecules like carbon dioxide and water using sun's energy is called Photosynthesis.


11. ANAEROBIC RESPIRATION: The process of respiration taking place in absence of air(oxygen) is called Anaerobic respiration.


12. AEROBIC RESPIRATION: The process of respiration taking place in presence of air(oxygen) is called Aerobic respiration.


13. TRANSPORTATION: The process of transfer of various materials like food, carbon dioxide, metabolic wastes, hormones, etc. from one organ to another in the body is called Transportation.


14. ARTERY: The blood vessel carrying blood from heart to other organs of the body is called Artery.


15. VEIN: The blood vessel carrying blood from different organs of the body to heart is called vein.


16. TRANSPIRATION: The loss of water in the form of vapour from the aerial parts of the plant is called Transpiration.


17. TRANSLOCATION: The transport of products of photosynthesis (food) from leaves to the other parts of the plant is called Translocation.


18. COORDINATION: The working together of different systems in the body so that the body acts as a harmonious (whole) unit is called Coordination.


19. REFLEX ACTION: A sudden unconscious and involuntary (automatic) response of effectors to the stimulus is called Reflex action.


20. REFLEX ARC: The pathway, involving the effector organ, sensory nerve, spinal cord and motor nerve, through which reflex action is performed is called Reflex Arc.


21. CENTRAL NERVOUS SYSTEM: The nervous system formed by the brain and the spinal cord is called the Central Nervous System.


22. Neuron: Neuron is the structural and functional unit of nervous system


23. SENSORY NEURON: The neuron which conveys an impulse(message) from an organ to the brain or spinal cord is called Sensory Neuron.


24. MOTOR NEURONE: The neuron which conveys a message from brain or spinal cord to the effector organ is called Motor Neuron.


25. SYNAPSE: The junction between the axon of one neuron and the dendrite of another neuron through which an impulse is transmitted between two neurons is called a Synapse.


26. STIMULUS: An external factor (environmental factor) to which an organism responds is called a Stimulus.


27. TROPISM: The directional growth of a plant in response to a stimulus is called Tropism.


28. PHOTOTROPISM: The directional growth (response) of a plant towards light is called Phototropism.


29. GEOTROPISM(GRAVITOTROPISM): The directional growth of a plant in the direction of gravitation or against it is called Geotropism.


30. HYDROTROPISM: The directional growth of a plant (roots) towards water is called Hydrotropism.


31. CHEMOTROPISM: The directional growth of a plant organ towards specific chemicals is called Chemotropism.


32. REPRODUCTION: A process by which living organisms produce organisms similar to them is called Reproduction.


33. VARIATION: The difference between individuals of the same species and the progeny of same parents is called Variation.


34. FISSION: The breaking of an unicellular organism after growth in two or more parts each of which then behaves as an individual organism is called Fission.


35. BINARY FISSION: The breaking of an organism into two exactly similar organisms which then grow and live as an independent organism is called Binary fission.


36. MULTIPLE FISSION: The breaking of an organism into several similar organisms each of which then behaves as an independent organism is called Multiple Fission.


37. FRAGMENTATION: The breaking up of a multicellular organism into smaller pieces and the development of an independent organism from each of these pieces is called Fragmentation.


38. REGENERATION: The capability of an organism to give rise to new individual organisms from their body parts whereby each part develops into a new organism is called Regeneration.


39. BUDDING: The formation of a bud-like structure on the body of an organism which grows as exact replica of the parent organism and then gets detached from it to behave as an independent organism is called Budding.


40. VEGETATIVE PROPAGATION: The development of a new plant from parts of root, stem, or leaves under appropriate conditions is called Vegetative Propagation.


41. ASEXUAL REPRODUCTION: The method of reproduction in which fusion of two gamates is not involved, i.e. the development of a new organism does not require two parents, is called Asexual Reproduction.


42. SEXUAL REPRODUCTION: The method of reproduction in which the fusion of a male gamate and a female gamate results in the development of a new organism is called Sexual Reproduction.


43. UNISEXUAL ORGANISM: An organism which possesses either the male sex organ or the female sex organ is called Unisexual organism.


44. BISEXUAL ORGANISM: An organism which possesses both male and female sex organs is called Bisexual organism.


45. FERTILISATION: The fusion of a male gamate with a female gamate resulting in the formation of a zygote is called Fertilisation.


46. GERMINATION: The development of a seedling from the seed under appropriate conditions is called Germination.


47. ZYGOTE: The diploid gamete formed by the fusion of a male gamete with a female gamete is called a Zygote.


48. GAMETE: A gamete is a haploid sex cell, either a sperm or an ovum, containing half number of chromosomes.


49. PUBERTY: The stage of the life of a human being at which the sexual organs become functional along with certain characteristic changes in body, voice, behaviour,etc.


50. MENSTRUAL CYCLE: The sexual cycle in a female which is repeated periodically every month and involves a series of phenomena from ovulation to the discharge of unfertilised egg with blood from vagina is called Menstrual Cycle.


51. MENSTRUATION: The periodic discharge of unfertilised ovum along with disintegrated tissues of uterus wall and blood, which lasts for about 3-5 days, is called Menstruation.


52. REPRODUCTIVE HEALTH: Prevention of diseases occurring through reproductive system and sexual contact by proper measures and cleanliness to maintain healthy state of the body is called Reproductive Health.


53. HEREDITY: The transmission of certain biological characteristics from parents to the offspring is called Heredity.


54. GENETICS: The branch of science which deals with heredity and variation in organisms is called Genetics.


55. EVOLUTION: The gradual cumulative change in the characteristics of organisms of the related species over a long period of time (over many generations) is called Evolution.


56. SPECIATION: Speciation is a process by which new species of organisms arise from the existing ones.


57. INHERITED TRAIT: A characteristic of an organism induced by a change in its genes is called an Inherited Trait.


58. ACQUIRED TRAIT: A characteristic of an organism which develops as a response to the environmental change and which is not inherited one is called an Acquired Trait.


59. HOMOLOGOUS ORGANS: The organs showing similarities in origin but performing different functions (in different organisms) are called Homologous Organs.


60. ANALOGOUS ORGANS: The organs showing different origin but performing similar functions (in different organisms) are called Analogous organs.


61. FOSSILS: Remains (or impressions), of once living organisms, which have been preserved within the layers of rocks over the years are called Fossils.


62. POLLINATION: The transfer of ripe pollen from an anther to the stigma of a flower of the same species is called Pollination.


63. SELF-POLLINATION: When pollen is carried from an anther to the stigma of the same flower or another flower on the same plant, it is called Self-pollination.


64. CROSS-POLLINATION: When the pollen is transferred from a flower of one plant to a flower of another plant of the same species, it is called Cross-pollination.


65. ENVIRONMENT: The physical surroundings and living organisms with which an organism interacts is called Environment.


66. BIODEGRADATION: The breaking down of substances into simpler molecules by the activity of micro-organisms is called Biodegradation.


67. ECOSYSTEM: A community of interdependent organisms together with the environment they inhabit and with which they interact is called an Ecosystem.


68. PRODUCERS: The organisms which produce food from natural simple inorganic molecules and trap sun's energy in it are called Producers.


69. CONSUMERS: The organisms which utilise food and energy from the preceding trophic level (either a producer or itself a consumer) are called Consumers.


70. Decomposers: The organisms which decompose organic waste materials and dead bodies of organisms into simpler substances are called Decomposers.


71. FOOD CHAIN: A series of organisms which are interlinked with one another for their requirements of food and energy is called a Food chain.


72. FOOD WEB: A complex network of many interlinked food chains is called a Food web.


73. BIOMAGNIFICATION (BIOLOGICAL MAGNIFICATION): The accumulation of non-biodegradable pollutants in the organisms of a food chain so that at each successive trophic level the amount of the substance relative to the biomass is increased is called Biomagnification.


74. BIODIVERSITY: The existence of organisms of different species as well as different organisms of same species in an ecosystem is called Biodiversity.


75. WILDLIFE: A combination of organisms, both plants and animals, which forms the population of a forest ecosystem is called Wildlife.