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Life Process, Earth happens to be the only known planet having life. There are beings which live, die, and become part of nature again. The living organism can be differentiated from the inanimate, entities on various parameters of life processes., Maintenance of living organism is essential even if they are moving, resting or even, sleeping. The processes which together perform the function of maintenance of 'life' are called as, life processes. Nutrition, respiration, circulation, excretion are the examples of essential life, processes., In unicellular organisms, all these processes are carried out by that single cell., In multicellular organisms, well-developed systems are present to carry out the processes., Nutrition, The process of acquiring food that is needed for nourishment and sustenance of the, organism is called nutrition. There are two main modes of nutrition, autotrophic and, heterotrophic. Heterotrophic nutrition has subtypes as holozoic, saprophytic and parasitic, nutrition., Autotrophic Nutrition, The word Autotrophic has been derived from the word “auto” & “trophe” which means, “Self” ‘Nutrition’. If an organism can nourish itself by making its own food using sunlight or, chemicals such mode of nutrition is called as autotrophic nutrition. It is of two types i.e., Photoautotrophs & Chemoautotrophs, * Plants photosynthesize (use light energy) and are called photoautotrophs. For example:Algae, Cyanobacteria, Grasses, Phytoplanktons etc., * Few bacteria use chemicals to derive energy and are called chemoautotrophs. For, example:- Sulphur-oxidising Bacteria, Iron-oxidising Bacteria, Nitrogen-fixing, Bacteria etc., Photosynthesis, Photosynthesis is the important process by which food is formed. The plants make food, using sunlight and water, which provides nourishment to other organism and themselves., Chlorophyll present in the green parts absorbs light energy., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 1

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This light energy is used to split water into hydrogen and oxygen. Hydrogen is then used, to reduce carbon dioxide into carbohydrates, typically glucose. Chlorophyll is essential for, photosynthesis and stomata facilitate intake of carbon dioxide., Stomata, Stomata are pores or minute openings on the leaves that help in exchange of gases. They are, mostly found on the underside of the leaf. Each stoma is guarded by guard cells and are found in, open and closed state, which control the opening and closing of the pore. The exchange of gases, takes and transpiration takes place through stomata., , Heterotrophic Nutrition, When an organism depends on others for food, such a mode of nutrition is called, as a heterotrophic mode of nutrition., These organisms depend on autotrophs for their nutritional requirements., E.g. Animals which eat plants as their food are called herbivores., Animals which eat other animals as their food are called carnivores., Types of Heterotrophic Nutrition, Saprophytic, Parasitic and Holozoic nutrition are all types of heterotrophic nutrition., 1) Saprophytic Nutrition, The word Saprophytic has been derived from two words i.e. “Sapros” and “Phyton”, which means ‘rotton’ ‘plant.’ In this type of nutrition the organism feed on, , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 2

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dead and decaying organic matter of plants and animals. Such mode of nutrition is called, saprophytic nutrition and the organisms are called Saprotrophs. The food is partially digested, outside the body and then it is absorbed. E.g. Fungi like Rhizopus, Mucor, Yeast, Mushrooms, etc. and many Bacteria are saprophytes., 2) Parasitic Nutrition, The word Parasitic has been derived from two words i.e. ‘Para’ and ‘sitos’ which means, ‘besides’ ‘food.’ In this type of Nutrition the organisms (parasite) depends on another organism, (host) for its nutritional requirement. Such mode of nutrition is called parasitic mode of nutrition., These organisms live on the body or in the body of a host organism and derive the nutrients, directly from the body of the host., For example:- Cuscuta, Orchids, Ticks, Lice, Leeches, Tapeworm etc., 3)Holozoic Nutrition, The mode of nutrition in which animals take their food as a whole is called as, holozoic nutrition. In holozoic nutrition, food passes through five steps as ingestion, digestion,, absorption, assimilation and egestion., For example Amoeba and all the animals such as cow, dog, cat etc., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 3

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Nutrition in Amoeba, Amoeba feeds by holozoic mode of nutrition. It engulfs the food particle using pseudopodia, the, process is called as phagocytosis. The engulfed food gets enclosed in a food vacuole. As the food, vacuole passes through the cytoplasm, digestion, absorption and assimilation take place. When, the food vacuole opens to outside, egestion of undigested food takes place., , Nutrition in Amoeba, Nutrition in Paramecium, Paramecium is a unicellular organism which, exhibit holozoic nutrition where intracellular, digestion takes place. However, they have cilia, , Nutrition in Paramecium, , that help them to engulf the food through the oral groove. A food vacuole is created enclosing, the food. It moves through the cytoplasm, the process is called cyclosis., , Food, , digested in the food vacuole is absorbed by the cytoplasm. pore or cytopyge. Undigested food is, given out to a tiny pore called anal pore or Cytopyge., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 4

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Difference between Autotrophic and Heterotrophic Nutrition, , S.No., , Autotrophic Nutrition, , Heterotrophic Nutrition, , 1, , Organisms prepare its own food., , Organisms, , depends, , on, , other, , organisms for their food., 2, , Food is prepared in from Co2 Food can not prepared from Co2 and, and, , water, , in, , presence, , of water., , sunlight., 3, , Food is generally prepared in a Food can be obtained any time., day., , 4, , They are producers in the food They are consumers in the food, chain., , 5, , They are capable of storing They are not capable of storing, sunlight and chemical energy., , 6, , energy., , They cannot move from one They can move from one place to, place to another., , 7, , chain., , another in search of food., , In autotrophs the process of In, digestion is absent., , heterotrophs, , the, , process, , of, , digestion is required to convert, complex molecules in to simpler., , 8, , This type of nutrition takes place This type of nutrition takes place in, in green plants & certain bacteria animals and insectivores plants, like blue green algae., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 5

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Nutrition in Humans, Humans are omnivores, they can eat plant-based food as well as animal-based food. Being more, complex, humans have a very complicated nutrition system. The digestive system has an, alimentary canal and associated digestive glands, which together function to nourish the body., Nutrition in Humans, Humans are omnivores, they can eat plant-based food as well as animal-based food. Being more, complex, humans have a very complicated nutrition system. The digestive system has an, alimentary canal and associated digestive glands, which together function to nourish the body., There are five stages in human nutrition; Ingestion, Digestion, Absorption, Assimilation and, Egestion. Out of which four stages i.e. ingestion, digestion, absorption and egestion take place in, the alimentary canal while assimilation of food takes place in the whole body., Alimentary Canal, Alimentary canal in humans is a long, tube of varying diameter. It starts with, mouth, , and, , ends, , with, , the, , anus., , Oesophagus, stomach, small intestine and, , Digestive System of Man, , large intestine are the parts of the, alimentary canal., Mouth, It is the opening of the alimentary canal, which helps in ingestion of food. The, buccal cavity is present behind the mouth, is also commonly referred as mouth. The, buccal cavity has teeth and tongue. The, set of teeth helps in mastication of food, while as tongue has taste buds on it, which, helps inglands, tasting, the also, food.in the buccal, The salivary, open, , Structure of Man Digestive System, , cavity and pour saliva which initiates the process of digestion., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 6

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Teeth, Teeth are the hard structures, present in the buccal cavity. They, help us to cut, shear and masticate, the food we eat. Vertical section, of a tooth shows four layers as, enamel,, , dentine,, , cement, , and, , dental pulp. Enamel is outermost,, shiny, highly mineralized and, hardest part of the human body., Dentine makes the bulk of the, tooth and contains 70% inorganic, , Structure of a Tooth, , salts., Cement is present at the lining of a tooth and bony socket. Dental pulp is the central soft, part of a tooth and contains nerve endings, blood and lymph vessels along with connective tissue., There are four types of teeth in humans, Incisors, canines, molars and premolars, each with a, specific function. Incisors cut the food, canines tear the food while molars and premolars crush, it. The dental formula in adult humans is 2:1:2:3., Dental Carries:Dental carries or tooth decay causes gradual softening of enamel and dentine., It starts when bacteria acting on sugars present in oral cavity produce acids that softens the, enamel., Masses of bacterial cells together form dental plaque due to which saliva cannot reach tooth, surface to neutralize the acid., Brushing the teeth after eating removes the plaque. If untreated, microorganism may invade the, pulp causing inflammation and infection., Oesophagus & Stomach, Oesophagus, The swallowed food passes into the oesophagus., It is a muscular tube, about 25 cm long, with a sphincter (valve/opening) at each end., Its function is to transport food and fluid, after being swallowed, from the mouth to the stomach., 7, Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe

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Food is pushed down by peristaltic movements., Stomach, The stomach is thick-walled bag or sac-like structure situated in the upper part of abdominal, cavity below the Diaphragm., Its receives food from the oesophagus at one end and opens into the small intestine at the other, end., The inner lining of the stomach secretes mucus, hydrochloric acid and digestive juices., Food is churned into semi-solid mass in the stomach and is called chyme., Enzymes present in the gastric juice break down the food., Hydrochloric acid helps in partial digestion of proteins and also kills harmful bacteria., Mucus secreted by the wall of stomach resists the action of HCl on itself., Small Intestine, The small intestine is the longest part of the alimentary canal, about 20 feet long in humans., It has regions, duodenum, the region which follows stomach, jejunum is the middle part and, ileum is the later region which continues further into the large intestine., The internal surface of the small intestine is folded into finger-like projections called villi., A common pancreatic duct from pancreas and liver opens into the duodenum., Most of the chemical digestion and absorption takes place in the small intestine., Large Intestine, Large intestine in humans is about 5 feet long., It has two regions, colon (about 1.5 m) and rectum (10 cm in length in the adult)., The region of large intestine after ileum is called colon while the last part is called rectum., Colon has three regions as, ascending colon, transverse colon and descending colon., At the base of ascending colon, a small finger-like out-growth is seen and is called an appendix., It houses many useful bacteria required for digestion of food., Rectum opens to outside by anus., The anus has internal and external anal sphincters., Physiology of Digestion, Mechanical digestion of food takes place in the buccal cavity where teeth masticate the food,, saliva gets mixed and it turns into a bolus., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 8

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Digestion of starch starts in the buccal cavity itself, with the action of salivary amylase present in, the saliva., Salivary amylase converts starch into maltose., In the stomach, the churning of food takes place due to the muscular contraction and relaxation, of its wall. It breaks down the food into simpler substances., Digestion of proteins starts in the stomach with the action of pepsin. Proteins are broken down, into smaller fragments called peptide by the action of pepsin., The bolus after mixing with gastric juice, turn into a fine soluble form known as the chyme., Chyme enters into the small intestine where complete digestion takes place due to the action of, various enzymes present in the pancreatic juice, bile and intestinal juice., The digested food is completely absorbed by the villi and microvilli of the small intestine., Undigested food then enters into the large intestine., Colon is responsible for absorption of water and salts whereas rectum stores the undigested food, temporarily before defecation., , Digestive System in Other Animals, Digestive systems in different animals vary in structure and function., The structure of the digestive system depends on the food habits of the animal., Alimentary canal in herbivores is long as the cellulose content of their plant-based diet takes a, long time to digest., On the other hand, alimentary canal of carnivorous animals is comparatively shorter because, meat gets digested faster., , Digestive Glands, Several glands produce digestive juices that help in digestion of the food., Salivary glands, Gastric glands, Liver, Gallbladder, Pancreas are few to name., Salivary glands secrete saliva which initiates digestion in the mouth itself., Gastric glands present in the wall of the stomach secrete hydrochloric acid and enzyme pepsin., The liver secretes bile which is stored in the gallbladder. Bile helps in digestion of fats., The pancreas secretes many digestive enzymes and its secretion is called as pancreatic juice., Enzymes like trypsin, chymotrypsin, lipase, amylase are present in the pancreatic juice., Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 9

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Pancreas, The pancreas is a long, flat gland present behind the stomach in humans., It is one of the major digestive glands and is of mixed nature i.e. endocrine as well as exocrine., As an endocrine organ, it secretes two hormones called insulin and glucagon which maintain the, blood sugar level., As an exocrine gland, it secretes pancreatic juice which is nothing but a mixture of many, digestive enzymes., The digestive enzymes secreted by pancreas include trypsin and chymotrypsin and proteases, which digest proteins., It also includes amylase which digests the starch content of the food., Pancreatic lipases are the pancreatic enzymes that help in digestion of fats., Functions & Role of HCl, Hydrochloric acid in the stomach is secreted by the gastric glands and its pH is usually between, 1.5 to 3.5, This acid serves following functions:, 1. Converts inactive pepsinogen and pro-rennin into active pepsin and rennin respectively., 2. Provides acidic medium for protein digestion., 3. Kills bacteria entered through food and prevents infection., 4. Prevents putrefaction of food in the stomach., 5. A thick layer of mucus secreted by the mucus glands of the stomach prevent itself from the, action of the gastric acid., 6. Excess acid damages gastric mucosa and causes gastric and duodenal ulcers., Functions & Role of Liver, The liver is the largest and major digestive gland of humans, Liver, in humans, is located in the upper right-hand portion of the abdomen., This organ is dark reddish brown in colour due to an extensive blood supply., Some of the important functions of the liver are as follows:, 1. It secretes bile that helps in digestion., 2. It filters the blood coming from digestive tract before passing it to the rest of the body., 3. It detoxifies various metabolites and drugs, 4. The liver makes proteins important for blood clotting and other functions., Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 10

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5. It stores and releases glucose as needed., 6. It processes haemoglobin, from the dead and worn out RBCs, for the iron content (the liver, stores iron)., 7. Conversion of harmful ammonia to urea takes place in the liver., Functions & Role of Digestive Juices, Pancreatic juice, bile and intestinal juice (succus entericus) are collectively called as digestive, juices., A common duct from digestive glands pours the secretions into the duodenum., Chyme enters into the small intestine where complete digestion takes place due to the action of, various enzymes., In the duodenum, the acidity of chyme is turned to alkalinity by the action of bile coming from, the liver. This is necessary for pancreatic enzyme action., Bile also emulsifies the fats into smaller globules., Pancreatic and intestinal amylases break down the carbohydrates into glucose., Trypsin and chymotrypsin are the proteases responsible for the breakdown of proteins finally, into amino acids., Lipase is the enzyme which acts on the emulsified fats and breaks them down into glycerol and, fatty acids., Water Absorption in Large Intestine, The large intestine is not involved in digestion of food or absorption of nutrients., The major function of the large intestine is to absorb water from the remaining indigestible food, matter and make the stool solid., The large intestine also helps in absorption of vitamins made by bacteria that normally live in the, large intestine., The innermost layer of the large intestine also acts as a barrier and protects from microbial, infections and invasions., Rectum stores the undigested food temporarily until defecation., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 11

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Respiration, Most of the living organisms need oxygen (from air) to obtain energy from food. This, oxygen reacts with the food molecules and burns them slowly to release energy. The released, energy is stored in the form of ATP molecules. The body can use this energy whenever require., Thus, the process of breakdown of food to release energy is called Respiration. It involves taking, of oxygen for burning of food and the eliminating the waste product (CO2 & H2O) from the, body., The process of Respiration is common to all the living organisms. It provide energy to the, cells. During this process two byproducts are formed i.e. CO2 & H2O. Out of these only CO2 is, considered the real waste product of respiration because its accumulation in the body is harmful, while as water (H2O ) is not harmful to the body. It is no doubt beneficial for the body. \ The, process is just opposite to photosynthesis because photosynthesis makes food (glucose) whereas, respiration breaks food by using O2 and releasing CO2 & H2O., Process of Respiration, The Glucose C6H12O6 .(six carbon compounds) is oxidized in the cells during respiration, and oxidation of glucose to Pyruvic acid (three carbon compounds) takes place in cytoplasm,, which is known as Glycolysis. It occurs in cytoplasm. The oxidation of glucose to pyruvic acid, does not require oxygen such as one molecule of glucose on glycolysis produces two molecules, of pyruvic acid. The pyruvic acid also known as pyruvate. It is ketonic carboxylic acid., The fat of pyruvate formed during respiration depends on whether oxygen is, present in the cells or not., If present in the cells, the pyruvate completely oxidised to CO2 and H2O and lot of, energy is produced (in the form of ATP)., If oxygen absent, pyruvate is converted to either ethanol and CO2 or Lactic acid, formation depending upon weather such process is take place in plant or animal cells and less, energy is released during this process., , Types of Respiration, Aerobic Respiration and Anaerobic Respiration, Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 12

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1) Aerobic Respiration, The process in which food (glucose) is completely breakdown into CO2 and H2O by, oxidation. During this process of aerobic repiration 1molecule of glucose (food) produce 38 ATP, molecules. All the organism which obtain energy by aerobic respiration cannot live without, oxygen. Such type of process is takes place in mitochondria., , 2) Anaerobic Respiration, This process is taking place in absence of oxygen. The breakdown of food (glucose) into, ethanol and CO2 and energy. This energy is then used by microorganism. Such process produces, less amount of energy which gets stored in the form of ATP mol. It is that type of respiration, which is taking place in absence of oxygen. Several microorganisms like yeast and some bacteria, obtain energy by anaerobic process., , During process one mol. of glucose produces 2 mol. of ATP. All organisms which obtain, energy by anaerobic respiration can live without oxygen., , Respiration in Plants, Like animals, plants also need energy. The plants get the same by the process of respiration. The, respiration in plants also involves the exchange of oxygen and CO2. So, oxygen and carbon, dioxide are also called as respiratory gases. The respiration in plants differ from that in animals, in three respects:1) All the parts of plants perform respiration individually. On the other hand, an animal’s, perform respiration as single unit., Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 13

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2) In plants little transport of respiratory gases from one part to other part of plant. On the, other hand, respiratory gases are usually transported over long distance inside an animal, during respiration., 3) In plants respiration occurs at a slow rate while in animals it occurs at much faster rate., , Respiration in Animals, The process of exchange gases varies in different animals., 1. Through Plasma Membrane, In unicellular animals, such as amoeba, exchange of gases takes place through cell surface. They, absorb oxygen from the surrounding air or water and give out carbon dioxide through plasma, membrane by diffusion., , 2. Through Body Wall or Skin, Tapeworms, earthworms, and leeches use their skin for the exchange of gases. The skin of, Earthworms is very thin and moistened. Many blood cells are spread on this skin. These blood, cells are known as capillaries. The exchange of gases occurs at capillaries. They die of suffocation if, their skin is dried up., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 14

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Amphibians such as frogs use more than one organ of respiration during their life. They breathe, through gills while they are tadpoles. Mature frogs breathe mainly with lungs and also exchange gas, with the environment through skin., , 3. Through Tracheal System, In insects like cockroaches, grasshopper, transportation of gas or gaseous exchange take place by a, special type of fine tubes is called tracheae., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 15

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Air containing oxygen enters through spiracles into the tracheal tubes. It then diffuses into the body, tissue and reaches every cell in the body. Carbon dioxide released from the cells goes into the, tracheal tubes and comes out through spiracles., 4. Through Gills, A majority of aquatic animals like fish and prawns breathe through special organs called gills. Gilla, are projections of the skin that help in using oxygen dissolved in water. Gills contain blood vessels, which help in exchange of gases., , Fish live in water. To get oxygen dissolved in water, fish gulp water through the mouth and pump it, over the gills. Water passes into the gill chamber through gill slits. In each chamber, the water, passes over the filaments. They absorb oxygen from the water and replace it with carbon dioxide, Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 16

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formed. The water then passes out through the gill opening and this process is repeated again and, again., 5. Through lungs, Amphibians, mammals, and birds exchange gases through special respiratory organs called lungs., Lungs are air-filled sac-like structures in the chest cavity. They are connected to the outside by a, series of tubes and small opening., , Biology Notes:- Govt. Higher Secondary School Bhalra, Bhaderwah, Dr Sanjeev Kumar # Stay Home # Stay Safe, , 17