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Friday, 14 April 2017

Definitions, Class 7, Science, NCERT



                  Cha.1ST NUTRITION IN PLANTS
1.      Nutrients: Carbohydrates, fats, protein, vitamins and minerals are the components of food. These components of food are necessary for our body and are called nutrients.
2.      Nutrition: The mode of taking food by an organism and its utilization by the body is called nutrition.
3.      Autotrophs: Green plants synthesize their food themselves by the process of photosynthesis. They are called autotrophs.
4.      Heterotrophs: Animals and most other organisms take in readymade food prepared by the plants. They are called heterotrophs.
5.      Stomata: Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’. Such pores are called stomata.
6.      Photosynthesis: The process by which plants synthesize their food using carbon dioxide and water in the presence of sunlight is called photosynthesis.
7.      Host: Parasite plant takes readymade food from the plant on which it is climbing. The plant on which it climbs is called the host.
8.      Parasite: An organism which lives in or on another organism and deprives the host of valuable nutrients is called a parasite.
9.      Saprotrophs: The mode of nutrition in which organisms take in nutrients from dead and decaying matter is called saprotrophic nutrition. Plants which use saprotrophic mode of nutrition are called saprotophs.
10.  Symbiotic relationship: Some organisms live together and share shelter and nutrients. This is called symbiotic relationship.                                            
                                     2nd. Nutrition in Animals
1. Digestion: The breakdown of complex  food into simpler substance is called digestion.
2. Alimentary canal: The food passes through a continuous canal which begins at buccal cavity and ends at anus. This canal is called alimentary canal.
3. Digestive system: The digestive tract and the associated glands together constitute a system. This system is called digestive system.
4. Ingestion: The process of taking food into the body is called ingestion.
5. Tooth decay: The bacteria present in our mouth breakdown the sugar present from leftover food and release acids. The acids gradually damage the teeth. This is called tooth decay.
6. Absorption: The digested food can pass into the blood vessels in the wall of small intestine. This process is called absorption.
7. Villi: The inner wall of the intestine have thousands of finger-like outgrowth. Which help in absorption of the digested food. These are called villi.
8. Assimilation: The absorbed substances are transported via the  blood vessels to different organs of the body where they are used to build complex substances such as the protein required by the body. This is called assimilation.
9. Egestion: The faecal matter is removed through the anus from time to time. This is called egestion.
10. Diarrhoea: Sometimes a person may need to pass watery stool frequently. This condition is called diarrhoea.
11. Cud: The partially digested food in the rumen of grass eating animals is called cud.
12. Rumination: The cud returns to the mouth in small lumps and the animals chews it. This process is called rumination.
13. Ruminant: The cud returns to mouth in small lumps and the animals chew it. This process is called rumination and these animals are called ruminants.
                                                       4th.   Heat
1.      Temperature: The measure of hotness of an object is called temperature.
2.      Thermometer:  A device used for measuring the temperature is called thermometer.
3.      Clinical thermometer:  The thermometer that measures our body temperature is called clinical thermometer.
4.      Conduction:  The  process  by  which  heat is transferred  from  the  hotter  end  to  colder  end  of  an  object  is  known  as  conduction.
5.      Conductor:  The  materials  which  allow  heat  to  pass  through  them  easily  are  called  conductor.
6.      Insulator:  The  material  which  do  not  allow  heat  to  pass  through  them  easily  are  called  insulator.
7.      Convection:  Transfer  of  heat  in  liquids  and  gases  is  causes  by  the   tendency  of  warmer   material  to  rise.  This process of heat transfer is called convection.
8.      Sea  breeze:  During  the  day  the  land  gets  heated  faster  than  the  water. The air over the land becomes hotter and rises up. The cooler air from the sea moves in towards the land to take its place. This air from the sea is called sea breeze.
9.      Land breeze: At night, the water cools down more slowly than the land. So, the cool air from the land moves towards the sea. This process is called land breeze.
10.  Radiation:  All hot bodies emit heat. This heat is transferred into the surroundings whether a medium is present or not. This process is called radiation.
                                                                              5. Acids and Bases
1.      Acid: Some substances taste sour and also turn blue litmus paper red. They are called acids.
2.      Base: Some substances taste bitter and feel soapy in touch. They turn red litmus paper blue. They are called bases.
3.      Acidic: The chemical nature of acids is called acidic.
4.      Basic: The chemical nature of bases is called basic.
5.      Indicators: Some special type of substances are used to test whether the substances are acidic or basic. These substances are called indicators.
6.      Neutral solutions: The solutions which do not change the colour of either red or blue litmus are known as neutral solutions.
7.      Neutral solution: The solution which does not change the colour of either red or blue litmus is called neutral solution.
                                                       6th. Physical and Chemical Changes
1.      Physical properties: Properties such as shapes, size, colour and state of a substance are called its physical properties.
2.      Physical Change: A change in which a substance undergoes a change in its physical properties are called physical change.
3.      Rusting: When a piece of iron is left in the open for some time, it acquires a film of brownish substance. This substance is called rust and the process is called rusting.
4.      Chemical change: A change in which one or more new substances are formed is called chemical change.
5.      Chemical reaction: A reaction in which one or more new substances are formed is called chemical change and a chemical change is also called chemical reaction.
6.      Galvanisation: The process of depositing a layer of zinc on iron is called galvanisation. 
                                                                     10. Respiration in organisms
1. Cell: The smallest structural and functional unit of an organism is called cell. 
2. Respiration: The process of breakdown of food in the cell with the release of energy is called respiration.
3. Anaerobic Respiration: The breakdown of food in the absence of oxygen is called anaerobic respiration.
4. Anaerobes: The organisms such as yeast that can survive in absence of air are called anaerobes.
5. Inhalation: The taking of air rich in oxygen into the body is called inhalation.
6. Exhalation: The giving out air rich in carbon dioxide is called exhalation.
7. Breathing: Taking in air rich in oxygen and giving out rich carbon dioxide with the help of respiratory organs is called breathing.
8. Breathing rate: The number of times a person breath in a minute is termed as the breathing rate of that person.
 9. Spiracles: The insects have a small openings for breathing on the sides of its body. These openings are called spiracles.
10. Tracheae: Insects have a network of air tubes for gas exchange. These are called tracheae.
11. Aerobic respiration: The breakdown of food in presence of oxygen is called aerobic respiration.
                                   Cha. 11: Transportation in Animals and Plants
1. Plasma: The fluid part of the blood is called plasma.
2. Haemoglobin: The red pigment present in the red blood cells is called haemoglobin.
3. Capillaries: The extremely thin tubes of the blood vessels are called capillaries.
4. Pulse: The throbbing caused due to the blood flowing in the arteries is called pulse.
5. Pulse rate: The number of heart beats per minute is called pulse rate.
6. Vein: The vessels which carry carbon dioxide-rich blood from all parts of the body back to the heart is called vein.
7. Artery: The vessels which carry oxygen-rich blood from the heart to all parts of the body called artery.
8. Atria: The two upper chambers of the heart are called atria.
9. Ventricle: The two lower chambers of the heart are called ventricles.
10. Excretion: The process of removal of wastes produced in the cells of the living organisms is called excretion.
11. Xylem: The vascular tissue for the transport of water and nutrients in the plants is called the xylem.
12. Phloem: The vascular tissue for the transport of food to the various parts of the plants is called phloem.
12. Reproduction in plant
1.      Reproduction: The production of new individuals from their parents is known as reproduction
2.      Unisexual flowers: The flowers which contain either only the pistil or only the stamens are called unisexual flowers.
3.      Bisexual Flowers: The flowers which contain both stamens and pistil are called bisexual flowers.
4.      Pollination: the transfer of pollen from the anther to the stigma of a flower is called pollination.
5.      Self-pollination: If the pollen lands on the stigma of the same flower, it is called self-pollination.
6.      Cross-pollination: When the pollen of a flower lands on the stigma of another flower of the same plant or that of a different plant of the same kind, it is called cross-pollination.
7.       Zygote: The cell which results after fusion of the gametes is called zygote.
8.       Fertilisation: The process of fusion of male and female gametes is called fertilisation.
9.       Sexual reproduction (in plants): Reproduction in which new plants are obtained from seeds is called sexual reproduction.
10.  Asexual reproduction (in plants): Reproduction in which new plants are obtained without seeds or spores is called asexual reproduction.
Chapter 13 Motion and Time
.
1.Speed: The distance covered by an object in a unit time is called speed.
2.  Average speed: The total distance covered by an object in the given time is called its average speed.
3. Uniform motion: If the speed of an object moving along a straight line is constant, the  motion is called uniform motion.
4. Non- uniform motion: If the speed an object moving along a straight line keeps changing its motion is called non- uniform motion.
5. Oscillatory motion: The to and fro motion of an object (like a simple pendulum) is called oscillatory motion.
6. Time period: The time taken by an object (like a simple pendulum) to complete one oscillation is called its time period.
              Chapter 14 Electric Current and its Effect
1.                  Battery: A combination of two or more cells is called battery.
2.                  Electric component: The different parts of an electric circuit like wire, electric cell, switch, electric bulb etc are called electric components.
3.                  Circuit diagram: The representation of an electric circuit using the symbols of its electric components is called circuit diagram.
4.                  Electromagnet: A current carrying coil of insulated wire wrapped around a piece of iron is called an electromagnet.
5.                   Fuse: The safety device based on the heating effect of electric current which protects the electric circuit from short circuit is called a fuse.
6. Heating effect of current: The wire gets hot when electric current passes through it. This property is called heating effect of current.
7. Magnetic effect of current: When electric current passes through a wire, it behaves like a magnet. This property is called magnetic effect of current.
                                                                                             
                                                                            15. Light
1. Erect image: If the image formed is upright, it is called an erect image.
2. Inverted image: If the image formed is upside-down, it is called an inverted image.
3. Magnified image: If the image formed is larger than the object, it is called magnified image.
4. Prism: A triangular piece of glass which is used to split white light into seven colours is called prism.
5. Real image: An image which can be obtained on screen is called a real image.
6. Virtual image: An image which cannot be obtained on a screen is called virtual image.
7. Reflection of light: A mirror changes the direction of light that falls on it. This change of direction by a mirror is called reflection of light.
                                                 16. Water: A Precious Resource
1. Aquifer: At some places groundwater is stored between layers of hard rock below the water table. This is called an aquifer.
2. Depletion: When a natural resource like water, forest, wild life etc gets reduced in number or quantity, it is called depletion.
3. Drip irrigation: A technique of watering plants makes use of narrow tubing which delivers water drop by drop at the base of the plant. This type of irrigation is called drip irrigation.
4. Groundwater: The water found below the water table is called groundwater.
5. Infiltration: The process of seeping of water into the ground is called infiltration.
6. Water recharge: The seepage of rainwater and the water collected in water bodies can replenish the underground water. This is called water recharge.
7. Water harvesting: The collection of rainwater in tanks for using it or for recharging the groundwater is called water harvesting.
8. Water table: The space between particles of soil and gaps between rocks are filled with water. The upper limit of this layer is called water table.
                                                               17th. The Forest our lifeline.
1.      Canopy: The branches of tall trees look like a roof over other plant in forest and it generally look like an umbrella. This is called a canopy.
2.      Crown: The branchy part of a tree above the stem is known as crown.
3.      Decomposers: The micro-organisms which convert the dead plants and animals to humus are known as decomposers.
4.      Deforestation: The cutting of large number of trees in the forest is called deforestation.
5.      Humus: Micro-organisms convert the dead plants and animals tissue into a dark coloured substance. This substance is called humus.
6.      Regeneration:  The conditions in the forest can help revert the effect of deforestation. The cut trees may grow again or new trees grow from seeds. This is called regeneration.
7.      Seed dispersal: The seeds of a plant can germinate and grow into new plants at different places because seeds and fruits are carried away by wind, water and animals. This carrying away of seed is called seed dispersal.
8.      Soil erosion: The removal of land surface by water, wind or ice is known as soil erosion.
9.      Understory: The plants growing under the canopy of forest is called understory.
10.   Food chain: In an ecosystem, an organism is eaten by another which in turn is eaten by some other. This forms a chain based on who eats whom. This is called food chain.
                  18. Wastewater Story
1. Aeration: The process in which air is bubbled in wastewater to reduce bad colour and bad smell is called aeration.
2. Aerobic bacteria: The bacteria which can live only in the presence of oxygen are called aerobic bacteria.
3. Anaerobic bacteria: The bacteria which can live even in the absence of oxygen are called anaerobic bacteria.
4. Biogas: The fuel gas that is formed by decaying organic matter is called biogas.
5. Contaminant: Sewage is a liquid waste. Most of it is water which has dissolved and suspended impurities. These impurities are called contaminants.
6. Sanitation: Arrangement to protect public health through the provision of clean drinking water and disposal of sewage is called sanitation.
7. Sewage: The wastewater released by homes, industries, hospitals, offices and other users is called sewage.
8. Sewer: The pipes that take away wastewater is called sewer.
9. Sewerage: The network of big and small sewer pipes is called sewerage.
10. Sludge: Solids such as faeces that settle down during wastewater treatment is called sludge.
11. Wastewater: The dirty water rich in lather mixed with oil, black-brown in colour that goes down the drain from sinks, showers, toilets, laundries etc. is called wastewater.







                                                                               

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