Life Processes - Class 10th Science

Important points:


  • Nutrition: intake of materials inside the body which help to grow, develop, synthesis proteins and other substances essential in the body is called nutrition.
  • Autotrophs: Organisms which use simple inorganic materials like carbon dioxide and water to prepare their food are called autotrophs.
  • Heterotrophs: The organisms which use complex substances and break them in to simpler ones by using biocatalysts to obtain the energy are called heterotrophs.
  • Photosynthesis: The process of converting marterials like carbon dioxide and water into carbohydrates in presence of sunlight and chlorophyll is called photosynthesis.
  • Stomata: Tiny pores present on the leaves are called stomata. They help in exchange of gases essential for photosynthesis. Closing and opening of stomata is controlled by guard cells.
  • Parasitic Nutrition: Organisms when derive food from plants and animals without killing them are called parasites  and mode of nutrition is called parasitic nutrition.
  • Unicellular organisms take in food by the process of diffusion.
  • In human beings, food is digested as it passes through alimentary canal. Different juices that mixes with food are salivary amylase(saliva), pepsin(gastric gland), bile juice(liver), pancreatic juice(pancreas), trypsin and lipase.
  • Respiration: The release of energy by breaking of  glucose molecule into simpler molecules like water and carbon dioxide is  called respiration.
  • Aerobic respiration: The respiration in which breakdown of pyruvate takes place in presence of oxygen is called aerobic respiration.
  • Anaerobic respiration: When pyruvate is broken down into ethanol and carbon dioxide in absence of oxygen then it is called anaerobic respiration.
  • The build-up  of lactic acid in muscles during sudden activities due to lack of oxygen causes cramps.
  • The different organs involved in human respiration are nasal passage, throat, lungs and alveoli.
  • The transport of oxygen in our body is brought about by respiratory pigments called haemoglobin.
  • Plasma: The fluid medium of the blood is called plasma. Plasma helps in transport of food, carbon dioxide and nitrogenous waste products.
  • TBhe four chambers of the heart are right auricle, left auricle, right ventricle and left ventricle.
  • Ventricles have thicker muscular walls as they have to pump the blood into various organs.
  • Birds and Mammals have to keep their body temperature constant, so they require higher energy needs and hence they have separation of right side and left side of heart.
  • When blood goes through heart twice during each cycle then it is called double circulation.
  • Three types of blood vessels involved in transport of blood are : a) Arteries b)Veins c) Capillaries.
  • Arteries supply oxygenated blood to different parts of body. Blood in arteries is under great pressure hence they have thick elastic walls.
  • Veins collect deoxygenated blood from different parts of body and bring it to heart. They do not have thick walls but they have valves to ensure that blood flows in one direction.
  • One celled thick blood vessels which comes in contact with individual cells of the body are called capillaries.
  • Blood platelets help to minimize the loss of blood from inured part by forming a clot.
  • Lymph(tissue fluid) carries digested and absorbed fats from intestine and drains excess fluid from extra cellular space in to the blood.
  • Xylem vessels present in plants help to conduct water and minerals from soil to leaves.
  • Phloem vessels transports products of photosynthesis from leaves to other parts of plants.
  • Transpiration: The loss of water in the form of vapors from the aerial parts of plants is called transpiration. Transpiration helps in (a) Absorption and upward movement of water and minerals from roots to leaves (b) Temperature regulation.
  • Translocation: Transport of soluble products called translocation.
  • Excretion: The biological process of removal of harmful metabolic wastes from the body is known as excretion.
  • Kidneys help to remove nitrogenous waste products from the blood . The filtration units present in kidneys are nephrons.
  • Oxygen, carbon dioxide and water are the main excretory products in plants. Besides these resins and gums are excreted by plants.