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Nutrition Chapter 1 NUTRITION CHAPTER CONTENTS autotrophs. (Gk. autos-self, trophe-nourishment). e.g., Ferrobacillus (iron bacterium). Nutrition Type of Nutrition Heterotrophic Nutrition : It is a mode of nutrition in which the organisms Autotrophic Nutrition obtain readymade organic food from outside Heterotrophic Nutrition sources. The organisms that depend upon outside Digestive system of Human sources for obtaining organic nutritens are called heterotrophs. Heterotrophic nutrition is of three Alimentary canal types - saprophytic, parasitic and holozoic. TYPE OF HETEROTROPHIC NUTRITION NUTRITION The process of intaking the food & utilization of 1. Saprophytic or Saprotrophic Nutrition : food is called nutrition. It is a mode of heterotrophic nutrition in which food is obtained from organic remains like dead Nutrient : organisms, excreta, fallen leaves, broken twigs, food The different component of food that have distinct articles, etc. Organisms performing saprophytic functions like providing energy, materials for nutrition are called saprophytes. body building, maintenance & regulation of 2. Parasitic Nutrition : metabolism are called nutrient. It is a mode of hetrotrophic nutrition in which a For example - Proteins, Minerals, Vitamin, living organisms flourishes by obtaining food from Carbohydrates, fats. another living organism. The lving organisms TYPE OF NUTRITION which obtains food and shelter from another organism is called parasite. The organism which Autotrophic Nutrition : provides food and shelter to a parasite is known as It is a mode of nutrition in which organisms are able host. An external plant parasite is Cuscuta to build up their own organic food from inorganic (Amarbel). It is a non-green plant that sends raw materials with the help of energy. The organism haustroria or sucking roots into host plant for performing autotrophic nturtion are called obtaining food and water. 3. Holozoic Nutrition : It is a mode of heterotrophic nutrition which involves intake of solid pieces of food. Since solid food is taken in, holozoic nutrition is also called ingestive nutrition. The food may consist of another animal, plant or its parts. Depending upon the source of food, holozoic organisms are of three types – Herbivores, carnivores, omnivores. Herbivores : (L.herba-plant, vorare-to eat). They are holozoic organisms which feed on plants or plant parts, e.g., Cow, Buffalo, Deer, Goat, Rabbit, Grasshopper, Elephant, Squirrel, Hippopotamus. Carnivores : They are animals which feed on other animals. Carnivores are also called predators they hunt, kill and feed on their preys, e.g. Lion, Tiger, Leopard, Snake, Hawk. Omnivores : (L.omnis-all, vorare-to eat). They are holozoic organisms which feed on both plant and animal materials, e.g. Cockroach, Ant, Pig, Crow, Rat, Bear, Dog, Humans. Nutrition in Amoeba : Protozoan protests carry out holozoic nutrition through intracellular digestion. Figure : HOLOZOIC NUTRITION IN AAMOEBA (i) Ingestion : Some protests can ingest food particle from any As soon as Amoeba comes in contact with a food point on the surface (e.g., Amoeba) while others particle or prey, it throws pseudopodia all around have fixed points for the same (e.g., the same. The tips of encircling pseudopodia fuse Paramoecium). Protozoans like Amoeba capture and the prey comes to lie in a vesicle or food with the help of temporary finger-like phagosome. This method of intake of food is called circumvallation. Amoeba can also ingest processes called pseudopodia. Protozoans like food by other methods like import, circumfluence (Paramoecium have small hair-like processes and invagination. called cilia.) Beating of cilia creates current in water that pushes food particle through cytostome DIGESTIVE SYSTEM OF HUMAN or cell mouth. The process of ingestion of solid Digestive system is a group of organs & associated food particle by a cell or unicellular organism is digestive glands that take part in ingestion, called phagocytosis. digestive absorption of food & egestion of undigestible matter. Digestive organs from a Pharynx : continuous canal called alimentary canal. It is short conical region that lies after the mouth ALIMENTARY CANAL CONTAINS cavity. FOLLOWING PARTS Oesophagous : Alimentary Canal in man is 9 metres long & It is a long narrow muscular tube which leads to consists of the following part the stomach. No digestive gland are present. Mouth : Stomach : Transverse slit like aperture. It lies below the diaphragm on the left side of abdominal cavity is J-shaped. Mouth Small Intestine : Salivary gland It is convoluted tube and differentiated into 3 Oesophagus regions, viz. Duodenum which is the first part of (food pipe) small intestine & is curved C-shaped; Jejunum, Liver Stomach comparatively longer & more coiled and Ileum, Gall bladder which is the last part of small intestine whose Duodenum inner surface is folded to form villi, which Small Intestine IIeum Pancreas absorbs the products of digestion. Large Intestine : Rectum Anus It is much shorter & wider than small intestine & is differentiated into three regions viz; Oral Cavity : Caecum which is small rounded blind sac from It is bounded by lips & has cheeks, gums, teeth & which vermiform appendix arises; tongue. Colon is the inverted U-shaped tube The food taken inside oral cavity is masticated i.e. The rectum opens to exterior through anus. mechanically broken into smaller particles before No digestion takes place in large intestine, only being swallowed. absorption of water takes place. The floor of the buccal cavity has a tongue In herbivores like horse, rabbit digestion of bearing taste buds. cellulose takes place in caecum. Man possesses teeth on both the jaws, there are 32 Absorption : teeth of four different types, namely incisors, canines, premolars & molars. In the small intestine (ileum) absorption of all digested materials takes place. Dental Formula : × 2 = x Assimilation : No.of teethinhalf partof upper jaw × 2 = x It is the process of utilisation of absorbed food for No.of teethinhalf partof lowerjaw various body functions. The absorbed nutrients 2 1 2 3 8 In Man I , C , Pm , M = x 2 are utilised to resynthesise complex molecules 2 1 2 3 8 like carbohydrates, protein & fats inside the cells. = Total 32 teeths Man cannot digest cellulose. Egestion : Voluntary cotraction of abdominal muscles It is the process of elimination of undigested help in egestion of faeces. food formed in the cells, or in the lumen of large intestine (colon & rectum) through the anus. TABLE : SUMMARY OF DIGESTION ENZYMES OF VARIOUS GLANDS WITH THEIR SECRETIONS AND END PRODUCTS OF DIGESTION IN MAN Name of S.No. Secretion Site of action Enzymes Food acts upon End product gland 1 Salivary glands Saliva Buccal cavity Salivary amylase Starch Maltose 2 Gastric glands Gastric Juice Stomach Pepsin Proteins Peptones & proteoses Renin Casein of milk Paracasein HCl Stomach — Pepsinogen Pepsin 3 Liver Bile Duodenum — Fats Emulsification of fats 4 Pancreas Pancreatic Duodenum Amylase Starch & Glycogen Maltose & Isomaltose Juice Trypsin Proteins Peptones & peptides Lipase Emulsified fats Fatty acids & glycerol Amino acids 5 Intestinal Intestinal Samall Erepsin Peptones & Peptides glands Juice intestine Glucose Maltase Maltose Glucose & fructose Sucrase Sucrose Glucose & galactose Lactase Lactose Monoglycerides & fatty Lipase Triglycerides acid Lubrication of faecal Mucous Large intestine — — matter Chlorophyll is green colour pigment. NUTRITION IN PLANTS Mechanism of Photosynthesis : Photosynthesis : Photosynthesis is divided in 2 main steps Photosynthesis is the primary mode of food (A) light reaction (B) dark reaction production in green plant. '' The process by which green plants synthesize food from simple Light reaction : substances carbon dioxide and water in the It is also called Hill Reaction. presence of sunlight is called Photosynthesis'' The process of photosynthesis can be represented It occurs in grana of thylakoids. in the form of chemical reaction, as given below : It is named as light reaction as it occurs only 6CO2 + 12H2O – C6H12O6 + 6H2O + 6O2 in presence of light. Carbon Water Glucose Water Oxygen dioxide Major Step : Absorption of light by chlorophyll. Photosynthetic Pigment : The light energy must be absorbed by a suitable Photolysis of water. pigment i.e. chlorophyll (green pigment). Reduction of CO2 to Carbohydrates. In this process ADP changes to ATP & C4 Cycle or Hatch & Slakcycle : inorganic phosphate. 4-C compound i.e. oxaloacetic acid (OAA). Release of oxygen into atmosphere. This cycle is found in many other tropical & Opening and Closing Stomata : subtropical monocots eg : Maize, Sorghum , Wheat, Oat, Pearl, millet etc. The opening and closing of stomata depend upon the turgid or flaccid state of the guard In dicots also many such plants are known eg : Amaranthus, Chenopodium, Atriplex, Euphorbia Subsidiary cells etc. In some families of dicots Compositae, Portulaceae, Nyctaginaceae. Crassulacean Acid Metabolism (CAM) : Nucleus Certain plants, especially succulents which Inner thick Wall of grow under extremely xeric (dry) condition, guard cells fix atmospheric CO2 in dark. Chloroplasts Outer thin wall of guard cell Since the process was first observed in the APERTURE CLOSED APERTURE OPEN plants belonging to family crassulaceae (eg. cells. When guard cells are in turgid state the Bryophyllum, kalanchoe etc.) It was termed stomatal aperture opens and when guard cells crassulacean
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