Nutrition Notes

NUTRITION autotrophs. (Gk. autos-self, trophe-nourishment). CONTENTS       e.g., Ferrobacillus (iron bacterium). Nutrition  Type of Nutrition  Heterotrophic Nutrition : Autotrophic Nutrition  obtain readymade organic food from outside Heterotrophic Nutrition sources. The organisms that depend upon outside sources for obtaining organic nutritens are called Digestive system of Human 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 : It is a mode of heterotrophic nutrition in which food food is called nutrition. is obtained from organic remains like dead  Nutrient :  It is a mode of nutrition in which the organisms 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 metabolism are called nutrient. For example - Proteins, Minerals, Vitamin, 2. Parasitic Nutrition :  It is a mode of hetrotrophic nutrition in which a living organisms flourishes by obtaining food from Carbohydrates, fats.  another living organism. The lving organisms  which obtains food and shelter from another TYPE OF NUTRITION 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 obtaining food and water. autotrophic nturtion are called  food particle by a cell or unicellular organism is called phagocytosis. 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. (i) Ingestion : Some protests can ingest food particle from any point on the surface (e.g., Amoeba) while others have fixed points for the same (e.g., Paramoecium). Protozoans like Amoeba capture food with the help of temporary finger-like processes called pseudopodia. Protozoans like (Paramoecium have small hair-like processes called cilia.) Beating of cilia creates current in water that pushes food particle through cytostome or cell mouth. The process of ingestion of solid Figure : HOLOZOIC NUTRITION IN AAMOEBA  As soon as Amoeba comes in contact with a food particle or prey, it throws pseudopodia all around the same. The tips of encircling pseudopodia fuse and the prey comes to lie in a vesicle or phagosome. This method of intake of food is called circumvallation. Amoeba can also ingest food by other methods like import, circumfluence and invagination. No.of teethin half part of upper jaw ×2=x No.of teethin half partof lower jaw DIGESTIVE SYSTEM OF HUMAN Digestive system is a group of organs & associated digestive glands that take part in ingestion, digestive absorption of food & egestion of undigestible matter. Digestive organs from a continuous canal called alimentary canal.  = Total 32 teeths  Pharynx : FOLLOWING PARTS cavity. Alimentary Canal in man is 9 metres long & consists of the following part   Mouth :  Oesophagous : It is a long narrow muscular tube which leads to the stomach. No digestive gland are present. Transverse slit like aperture.  Stomach :  It  Small Intestine : Oesophagus (food pipe) Liver Gall bladder Duodenum Small Intestine IIeum Anus It Pancreas Rectum  Large Intestine : It is much shorter & wider than small intestine & Oral Cavity : It is bounded by lips & has cheeks, gums, teeth & is differentiated into three regions viz;  tongue. The food taken inside oral cavity is masticated i.e. mechanically broken into smaller particles before being swallowed.  The floor of the buccal cavity has a tongue bearing taste buds.  is convoluted tube and differentiated into 3 regions, viz. Duodenum which is the first part of small intestine & is curved C-shaped; Jejunum, comparatively longer & more coiled and Ileum, which is the last part of small intestine whose inner surface is folded to form villi, which absorbs the products of digestion. Stomach   lies below the diaphragm on the left side of abdominal cavity is J-shaped. Mouth Salivary gland  2 1 2 3 8 , C , Pm , M = x 2 2 1 2 3 8 It is short conical region that lies after the mouth ALIMENTARY CANAL CONTAINS   In Man I Man possesses teeth on both the jaws, there are 32 teeth of four different types, namely incisors, canines, premolars & molars.  Dental Formula : ×2=x Caecum which is small rounded blind sac from which vermiform appendix arises;    Colon is the inverted U-shaped tube The rectum opens to exterior through anus. No digestion takes place in large intestine, only absorption of water takes place.  In herbivores like horse, rabbit digestion of cellulose takes place in caecum.  Absorption : In the small intestine (ileum) absorption of all digested materials takes place. large intestine (colon & rectum) through the anus.  Assimilation :  It is the process of utilisation of absorbed food for various body functions. The absorbed nutrients are utilised to resynthesise complex molecules like carbohydrates, protein & fats inside the cells.   Voluntary cotraction of abdominal muscles help in egestion of faeces. Man cannot digest cellulose.  Egestion :  It is the process of elimination of undigested food formed in the cells, or in the lumen of TABLE : SUMMARY OF DIGESTION ENZYMES OF VARIOUS GLANDS WITH THEIR SECRETIONS AND END PRODUCTS OF DIGESTION IN MAN S.No. Name of gland Secretion 1 Salivary glands Saliva 2 Gastric glands Gastric Juice Site of action Enzymes Food acts upon End product Starch Maltose Pepsin Proteins Peptones & proteoses Renin Casein of milk Paracasein Buccal cavity Salivary amylase Stomach HCl Stomach — Pepsinogen Pepsin 3 Liver Bile Duodenum — Fats Emulsification of fats 4 Pancreas Pancreatic Juice Duodenum Amylase Trypsin Lipase Starch & Glycogen Proteins Emulsified fats Maltose & Isomaltose Peptones & peptides Fatty acids & glycerol 5 Intestinal glands Intestinal Juice Samall intestine Erepsin Maltase Sucrase Lactase Lipase Peptones & Peptides Maltose Sucrose Lactose Triglycerides Amino acids Glucose Glucose & fructose Glucose & galactose Monoglycerides & fatty acid Mucous Large intestine — Lubrication of faecal matter —  dioxide NUTRITION IN PLANTS   Photosynthesis :   Photosynthesis is the primary mode of food production in green plant. '' The process by which green plants synthesize food from simple substances carbon dioxide and water in the presence of sunlight is called Photosynthesis'' The process of photosynthesis can be represented in the form of chemical reaction, as given below : 6CO2 + 12H2O – C6H12O6 + 6H2O + 6O2 Carbon Water  Photosynthetic Pigment : Glucose Water Oxygen The light energy must be absorbed by a suitable pigment i.e. chlorophyll (green pigment).  Chlorophyll is green colour pigment.   Mechanism of Photosynthesis :  Photosynthesis is divided in 2 main steps (A) light reaction (B) dark reaction  Light reaction :  It is also called Hill Reaction.   position (moves towards pore) due to which tension on the inner wall is released which also returns to its original position and stomatal aperture gets closed again. It occurs in grana of thylakoids. It is named as light reaction as it occurs only in presence of light.  Major Step :   Dark Reaction :    Absorption of light by chlorophyll.  In this process ADP changes to ATP &  This reaction is not dependent on light. It is also known as calvin – Benson Cycle or C3 cycle as first stable product is phosphogliceric acid (PGA) a 3 carbon compound. Photolysis of water. Reduction of CO2 to Carbohydrates. inorganic phosphate.  Release of oxygen into atmosphere.   C4 Cycle or Hatch & Slakcycle :    Opening and Closing Stomata :  The opening and closing of stomata depend upon the turgid or flaccid state of the guard  Inner thick Wall of guard cells Chloroplasts  APERTURE CLOSED APERTURE OPEN This cycle is found in many other tropical & subtropical monocots eg : Maize, Sorghum , Wheat, Oat, Pearl, millet etc. Subsidiary cells Nucleus 4-C compound i.e. oxaloacetic acid (OAA).  In dicots also many such plants are known eg : Amaranthus, Chenopodium, Atriplex, Euphorbia etc. In some families of dicots Compositae, Portulaceae, Nyctaginaceae.   Crassulacean Acid Metabolism (CAM) :  Outer thin wall of guard cell grow under extremely xeric (dry) condition, fix atmospheric CO2 in dark.  cells. When guard cells are in turgid state the stomatal aperture opens and when guard cells are in flaccid state the stomatal aperture closes. The inner wall of guard cells (towards pore) is thick and outer wall (towards other epidermal cells) is thin. When the turgor pressure of the guard cells is increased the outer thinner wall of the guard cell is pushed out (towards the periphery) due to which a tension is created on the inner thicker wall thus pulling the inner thicker wall towards the periphery thus leading to the opening of stomatal aperture. On the contrary when the guard cells are in a flaccid state the outer thinner wall of guard cells returns to original Certain plants, especially succulents which  Since the process was first observed in the plants belonging to family crassulaceae (eg. Bryophyllum, kalanchoe etc.) It was termed crassulacean acid metabolism (CAM).  The most characteristic feature of these plants is that their stomata remain open at night (in dark) but closed during the day (in light).  Thus, CAM is a kind of adaptation in succulents to carry out photosynthesis without much loss of water.