Class 10
subject science
chapter 6
Life process
All leaving things perform certain life processes like growth, excretion, respiration, circulation etc.
All the processes like respiration, digestion. which together keep the living organisms live and perform the job of body maintenance are called life processes.
Mode of nutrition
Nutrition plants
(1) Plants are autotrophs.
(2) Make their own food.
(3) Eat animals for their food.
Nutrition in animals.
(1) Animals are heterotrophs.
(2) Depends on plants or other.
Autotrophic nutrition :- It is a kind of nutrition in which inorganic materials like carbon dioxide, water etc. are utilised to prepare organic food by the process of photosynthesis.
Ex. Green plants.
The organisms which carry out autotrophic nutrition are called autotrophs (green plants)
Autotrophs used simple inorganic material and convert it into complex high energy molecules (carbohydrates)
Autotrophic nutrition is fulfilled by the process by which autotrophs take in carbon dioxide and water and convert these into carbohydrates in the presence of chlorophyll and sunlight is called photosynthesis.
Equation for photosynthesis
Raw materials for photosynthesis :-
** Sunlight - It is inorganic material.
** Chlorophyll - Sunlight absolved by chlorophyll.
** Carbon dioxide - Inters through stomata and oxygen is released as by product through stomata on leaf.
** Water - Water and dissolved materials like nitrogen, Phosphorus is etc, are taken up by the roots of the soil.
Site of photosynthesis :- Some cells contain green pigments which are cell organelles called chloroplast which contain chlorophyll.
** Chlorophyll absorb light energy.
** Conversion of light energy into chemical energy and splitting or breaking of water into hydrogen and oxygen.
** Reduction of carbon dioxide to carbohydrates.
Stomata :- It is tiny force present on the surface of the leaves.
Function of stomata :-
Exchange of gases like Oxygen and carbon dioxide.
Loses large amount of water (water vapour) during transpiration.
Heterotrophic nutrition :- kind of nutrition in which organisms do not processes the ability to synthesise their own food. They depend on autotrophs for their food supply directly or indirectly.
Ex. Animals, fungi.
Types of heterotrophic Nutrition :-
(1) Holozoic nutrition :- In this, animals take in solid food and breakdown inside the body.
Ex. Amoeba, animals.
(2) Saprophytic nutrition :- Organisms feed on dead, decay matter.
Ex. Fungi
(3) Parasitic nutrition :- Parasites live inside or outside other organisms (host) and derive nutrition from it.
Ex. Cuscuta (plant parasite), ticks etc
Organisms obtained their food :-
Unicellular organisms :- food is taken up through entire surface.
Ex. Amoeba, paramecium.
Nutrition in amoeba :-
:- Amoeba is a unicellular animal which follow the holozoic mode of Nutrition.
:- In holozoic nutrition, the digestion of food follows after the ingestion of food. Thus, digestion take place inside the body of the organism.
:- Holozoic nutrition happens in five steps ingestion, digestion, absorption, assimilation egestion.
Ingestion - The process of taking in the food.
Digestion - The process of breaking complex food substances into simple molecules.
Absorption - The process of absorption of digested food.
Assimilation - The process of utilisation of digested food for energy and for growth and repair.
Egestion - The process of removing undigested food from the body.
Amiba is a unicellular animal which follow the follow holozoic mode of nutrition. The cell membrane of amoeba keeps on protruding into pseudopodia. Amoeba surrounds food particle with pseudopodia and makes a food vacuole. The food vacuole contain food particle and water. Digestive enzymes are secreted in the food vacuole and digestion take place. After that, digested food is absorbed from the food vacuole. Finally the food vacuole moves near the cell membrane and undigested food is expelled out.
Nutrition in human beings :- Human being are complex animals, which have a complex digestive system. The human digestive system is composed of a alimentary canal and some accessory glands.
The alimentary canal is divided into several parts like oesophagus stomach small intestine large intestine rectum and anus. Salivary gland, liver and pancreas are the accessory glands which lie outside the elementary canal.
Human digestive system :-
Alimentary canal - The alimentary canal is basically a long tube extending from the mouth to the anus(mouth, oesophagus, stomach, small intestine,large intestine, anus). Various regions are specialised perform different functions.
Associated glands - Salivary gland, gastric gland, liver, pancreas
Mouth :-
** The mouth has teeth and tongue. Salivary gland are also present in the month.
** The tongue has gustatory receptors which receive the sense of taste.
** The tongue helps in turning over the food so that saliva can be properly mixed in it.
** Teeth help in breaking down the food into smaller particles so that, swellowing of food becomes easier.
Salivary glands :- Saliva makes the food slippery which makes it easy to swallow the food. Saliva also contains the enzyme salivary amylase or ptyalin. Salivary a mileage digestive starch and convert it into sucrose or maltose.
Oesophagus :- Taking food from mouth to stomach by peristaltic movement. (Contraction and expansion of muscles of the oesophagus)
Stomach :- Stomach is a back like organ. Highly muscular walls of the stomach help in churning the food.
** The walls of stomach secrets hydrochloric acid. which kills the germs, which may be present in food.
*" Hydrochloric acid makes the medium inside the stomach as acidic. The acidic medium is necessary for gastric enzyme to work.
** The enzyme pepsin secreted in the stomach does partial digestion of protein.
** The mucus, secreted by the walls of the stomach saves the inner lining of the stomach from getting damaged from hydrochloric acid.
Small intestine :- It is highly coiled tube like structure. It is the site of the complete digestion of carbohydrates, proteins and fats.
** Walls of small intestine secrets intestinal enzyme which convert carbohydrate into glucose, fats into fatty acid and glycerol, proteins into amino acid.
** It has finger like projection (villi) which help in the absorption of food into blood.
** It receives the secretion of the liver and pancreas.
Liver :- It is the largest organ in the human body. It manufacture bile, which gets stored in the gallbladder. From the gallbladder, while is released as and when required.
Pancreas :- It is situated below the stomach. It's secrets pancreatic juice which contain many digestive enzyme.
Ex - Trypsin lipase.
** Trypsin enzyme digest protein into amino acid.
** Lipase enzyme digest fat into fatty acid and glycerol.
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 which increases the efficiency of enzyme action.
Large intestine :- It absorb excess of water. The rest of the material is removed from the body via the anus.
** Large intestine is smaller than the small intestine.
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