CBSE – 10th Standard Science

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Class 10 Chapter 6 – Life Processes

LIFE PROCESSES

  • Movement of various types can be taken as an indication of life.
  • The maintenance of life requires processes like nutrition, respiration, transport of materials within the body and excretion of waste products.
  • Autotrophic nutrition involves the intake of simple inorganic materials from the environment and using an external energy source like the Sun to synthesise complex high-energy organic material.
  • Heterotrophic nutrition involves the intake of complex material prepared by other organisms.

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  • Stomata are tiny pores present on the surface of the leaves. Massive amounts of gaseous exchange takes place in the leaves through these pores for the purpose of photosynthesis.
  • Exchange of gases occurs across the surface of stems, roots and leaves as well. Since large amounts of water can also be lost through these stomata, the plant closes these pores when it does not need carbon dioxide for photosynthesis.
  • The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open
  • Nutrition in Human Beings

In human beings, the food eaten is broken down by various steps along the alimentary canal and the digested food is absorbed in the small intestine to be sent to all cells in the body

DIGESTIVE SYSTEM IN HUMANS

  • Digestion functions are taken care of by the gastric glands present in the wall of the stomach. These release hydrochloric acid, a protein digesting enzyme called pepsin, and mucus. The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin. The mucus protects the inner lining of the stomach from the action of the acid under normal conditions.
  • The exit of food from the stomach is regulated by a sphincter muscle which releases it in small amounts into the small intestine.
  • The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. Bile juice from the liver accomplishes this in addition to acting on fats. Fats are present in the intestine in the form of large globules which makes it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action. The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands which secrete intestinal juice. The enzymes present in it finally convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol
  • The digested food is taken up by the walls of the intestine. The inner lining of the small intestine has numerous finger-like projections called villi which increase the surface area for absorption
  • The unabsorbed food is sent into the large intestine where more villi absorb water from this material. The rest of the material is removed from the body via the anus. The exit of this waste material is regulated by the anal sphincter

EXCRETORY SYSTEM IN HUMANS

  • In human beings, excretory products in the form of soluble nitrogen compounds are removed by the nephrons in the kidneys

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RESPIRATORY SYSTEM IN HUMANS

  • During the process of respiration, complex organic compounds such as glucose are broken down to provide energy in the form of ATP. ATP is used to provide energy for other reactions in the cell.
  • Respiration may be aerobic or anaerobic. Aerobic respiration makes more energy available to the organism
  • Respiration may be aerobic or anaerobic. Aerobic respiration makes more energy available to the organism

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Circulatory system in humans

  • In human beings, the transport of materials such as oxygen, carbon dioxide, food and excretory products is a function of the circulatory system. The circulatory system consists of the heart, blood and blood vessels.
  • In human beings, the transport of materials such as oxygen, carbon dioxide, food and excretory products is a function of the circulatory system. The circulatory system consists of the heart, blood and blood vessels.

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Transportation in Plant

  • In highly differentiated plants, transport of water, minerals, food and other materials is a function of the vascular tissue which consists of xylem and

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