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Chapter 1:Chemical Reaction And Equations

Chapter 2:Acids, Bases and Salts

Chapter 3:Metals and Non-metals

Chapter 4:Carbon and Its Compounds

Chapter 5: Periodic Classification of Elements

Chapter 6: Life Processes

Chapter 10: Light Reflection and Refraction

Chapter 11:Human Eye and Colourful World

Chapter 12:Electricity

Chapter 13:Magnetic Effects of Electric Current

Chapter 14:Sources of Energy

Chapter 15:Our Environment

Chapter 16:Sustainable Management of Natural Resources

Life processes class 10 notes chapter 6

WHAT ARE LIFE PROCESSES?

  • The maintenance functions of living organisms must go on even when they are not doing anything particular
  • The processes which together perform this maintenance job are life processes
  • Nutrition, respiration, circulation, excretion are examples of essential life processe
  • In case of unicellular organisms, all these processes like taking in food, exchange of gases or removal of wastesare carried out by that single cell while in multi-cellular organisms, various body parts have specialised in the functions they perform.

NUTRITION: The process of providing or obtaining the food necessary for health and growth

Modes of nutrition: There are two main modes of nutrition
i) Autotrophic
ii) Heterotrophic.

Autotrophic Nutrition: Some organisms use simple food material obtained from inorganic sources in the form of carbon dioxide and water.

Photosynthesis:

  • It is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy
  • This material is taken in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll.
  • Carbohydrates are utilised for providing energy to the plant

Events occur during this process:

  • Absorption of light energy by chlorophyll.
  • Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
  • Reduction of carbon dioxide to carbohydrates.

chlorophyll: These green dots are cell organelles called chloroplasts which contain chlorophyll

Stomata:

  • The tiny pores present on the surface of the leaves help exchange of gases
  • large amounts of water can also be lost through these stomata
  • The opening and closing of the pore is a function of the guard cells.

Heterotrophic Nutrition: Heterotrophic nutrition is a type of nutrition in which organisms depend upon other organisms

Saprophytic Nutrition: organisms break-down the food material outside the body and then absorb it. Examples are fungi like bread moulds, yeast and mushrooms.

Parasitic Nutrition: organisms derive nutrition from plants or animals without killing them like cuscuta (amar-bel), orchids, ticks,

Nutrition in Amoeba:

i) The mode of nutrition in Amoeba is holozoic
ii) Amoeba takes in food using temporary finger-like extensions called pseudopodia and fuse over the food particle forming a food-vacuole
iii) Inside the food vacuole, complex substances are broken down into simpler ones and diffuse into the cytoplasm.

Nutrition Paramoecium,
i) The mode of nutrition in Paramoecium, is holozoic
ii) they have cilia that help them to cover the entire surface food through the oral groove.
iii) And forming a food-vacuole and digestion take place s

Nutrition in Human Beings:
i) humans are omnivores they eat various types of food
ii) There are five stages in human nutrition; Ingestion, Digestion, Absorption, Assimilation and Egestion.
Digestion process


  • first we take food in mouth and starting crushing the food with our teeths
  • A fluid called saliva secreted by the salivary glands
  • The food is mixed thoroughly with saliva and moved around the mouth while chewing by the muscular tongue
  • Saliva has to be broken into smaller molecules with the help of biological catalysts called enzymes
  • This enzyme called salivary amylase that breaks down complex molecule called starch to give sugar
  • The lining of canal has muscles that push the food forward
  • , the food is taken to the stomach through the food-pipe or oesophagus
  • The muscular walls of the stomach help in mixing the food
  • gastric glands present in the wall of the stomach help for digestion
  • 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.
  • a sphincter muscle help in releasing of food from the stomach into the small intestine
  • small intestine is the longest part of the alimentary canal
  • The length of the small intestine differs in various animals depending on the food they eat.
  • Note Herbivores eating grass need a longer small intestine to allow the cellulose to be digested. Meat is easier to digest, hence carnivores like tigers have a shorter small intestine.
  • The small intestine is the site of the complete digestion of carbohydrates, proteins and fats.
  • 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 So, 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
  • 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 internal surface of the small intestine is folded into finger-like projections called villi.
  • 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.

RESPIRATION:
i)Respiration means the exchange of gases.
ii)Breaking down of glucose into pyruvate: This happens in the cytoplasm. Glucose molecule is broken down into pyruvic acid. Glucose molecule is composed of 6 carbon atoms, while pyruvic acid is composed of 3 carbon atoms.
iii)Fate of Pyruvic Acid: Further breaking down of pyruvic acid takes place in mitochondria and the molecules formed depend on the type of respiration in a particular organism. Respiration is of two types, viz. aerobic respiration and anaerobic respiration. Respiration involves
Gaseous exchange: Intake of oxygen from the atmosphere and release of CO2 → Breathing.
Breakdown of simple food in order to release energy inside the cell → Cellular respiration
4)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.

Aerobic respiration: Breakdown of pyruvate using oxygen takes place in the mitochondria. This process breaks up the three-carbon pyruvate molecule to give three molecules of carbon dioxide and water is called aerobic respiration

Anaerobic respiration:: The pyruvate may be converted into ethanol and carbon dioxide. This process takes place in yeast during fermentation. Since this process takes place in the absence of air (oxygen), it is called anaerobic respiration

  • Different organisms use different methods for the intake of oxygen and expulsion of carbon dioxide.
  • plants exchange gases through stomata,
  • Fishes take in water through their mouths and force it past the gills where the dissolved oxygen is taken up by blood.
  • the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms

Respiration in human beings:

  • The air passing through the nostrils is filtered by fine hairs that line the passage
  • the air passes through the throat and into the lungs
  • Rings of cartilage are present in the throat. These ensure that the air-passage does not collapse.
  • The balloon-like structures in lungs which are called alveoli
  • The alveoli provide a surface where the exchange of gases can take place.
  • the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body
  • The blood brings carbon dioxide from the rest of the body for release into the alveoli,
  • Note: the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released
  • the respiratory pigment is haemoglobin which carry oxygen

TRANSPORTATION :

Transportation in Human Beings: Blood consists of a fluid medium called plasma which transports food, carbon dioxide and nitrogenous wastes in dissolved form

Our pump — the heart:

  • The heart is a muscular organ which is as big as our fist
  • the heart has four chambers
  • the heart has different chambers to prevent the oxygen-rich blood from mixing with the blood containing carbon dioxid
  • the oxygenated blood from the lungs has to be brought back to the heart
  • This oxygen-rich blood is then pumped to the rest of the body.
  • process:
  • Oxygen-rich blood from the lungs comes the left atrium.The left atrium relaxes and collecting this blood.
  • after blood is transferred to left ventricle
  • When the muscular left ventricle contracts in its turn, the blood is pumped out to the body.
  • De-oxygenated blood comes from the body to the right atrium,
  • transfers blood to the right ventricle, which pumps it to the lungs for oxygenation.
  • ventricles have thicker muscular walls than the atria
  • Valves: Valves ensure that blood does not flow backwards when the atria or ventricles contract.

Double Circulation

  • In the human body, blood circulates through the heart twice.>/li>
  • Once it goes through the heart during pulmonary circulation and second time during systemic circulation.
  • Hence, circulation in human beings is called double circulation

Blood pressure:

  • The force that blood exerts against the wall of a vessel is called blood pressure.
  • Blood pressure is measured with an instrument called sphygmomanometer.
  • The pressure of blood inside the artery during ventricular systole (contraction) is called systolic pressure
  • pressure in artery during ventricular diastole (relaxation) is called diastolic pressure
  • The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg.

blood vessels:

  • Blood vessels carry blood throughout the body
  • There three types of blood vessels; arteries, veins and blood capillaries.
  • Arteries are the vessels which carry blood away from the heart to various organs of the body and veins carry deoxygenated blood.
  • The smallest vessels have walls which are one-cell thick and are called capillaries. Exchange of material between the blood and surrounding cells takes place across this thin wall.

Platelets: The platelet cells which circulate around the body and plug these leaks of blood by helping to clot the blood at these points of injury.

Lymph: Atype of fluid also involved in transportation. This is called lymph or tissue fluid..Lymph is to carry absorbed digested fat from intestine and it also drains excess fluid from extra cellular space back into the blood.

Transportation in Plants:

  • The other kinds of raw materials needed for building plant bodies will also have to be taken up separately.
  • Food and water transportation takes place separately in plants
  • xylem moves water and minerals obtained from the soil
  • phloem transports food to other parts of the plant.

Transport of water:

Xylem tissue,:
  • Xylem tissue is made up tracheids, vessels, xylem fibres and xylem parenchyma.
  • xylem tissue is a continuous system of water-conducting channels reaching all parts of the plant.
  • Xylem creating a column of water that is steadily pushed upwards
  • Transpiration: The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration

Transport of food and other substances:

Phloem:
  • pholem tissue is made of Sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells .
  • The phloem is help for translocation of nutrients and sugar like carbohydrates, produced by the leaves to other of the plant .
  • Direction of pholem in both upward and downward directions.
  • the phloem transports amino acids and other substances.
  • Translocation:
    • This transport of soluble products of photosynthesis is called translocation
    • it occurs in the part of the vascular tissue known as phloem
    • s. The translocation of food and other substances takes place in the sieve tubes
    • Material like sucrose is transferred into phloem tissue using energy from ATP.
    • This increases the osmotic pressure of the tissue causing water to move into it

EXCRETION:

The biological process involved in the removal of these harmful metabolic wastes from the body is called excretion.
In unicellular organisms remove these wastes by simple diffusion from the body surface into the surrounding water

Excretion in Human Beings:
  • The excretory system of human beings includes a pair of kidneys, a pair of ureters, a urinary bladder and a urethra
  • Urine produced in the kidneys passes through the ureters into the urinary bladder where it is stored until it is released through the urethra.
  • Kidneys:
    • Kidneys are located in the abdomen, one on either side of the backbone
    • They are helping the filtration units of the human bod
    • it consiste a cluster of very thin-walled blood capillaries
    • each capillaries collecting the filtered urine
  • nephrons:


    kidney has large numbers of these filtration units called nephrons
    • They filtrate, such as glucose, amino acids, salts and a major amount of water and re-absorbed

Excretion in Plant:

  • Plants use different method for excretion than animals
  • Oxygen can be thought of as a waste product during photosynthesis
  • Excess water by transpiration
  • Other waste products are stored as resins and gums, especially in old xylem