sym sci nutrition

8/4/2019 Sym Sci Nutrition

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By : Antony A. Rai, Sebi John, Sean Thomas, Kevin

Gabriel, Tarush A. Kane



Nutrition is a source of materials to nourish the body. It provides the body with

materials from which it can produce energy and provides material to allowgrowth, maintenance, repair or reproduction to proceed.

Materials and Energy are required by all organisms. Some organisms usesimple food material obtained from inorganic sources in the form of carbonand water. These organisms, the Autotrophs, include green plants and somebacteria. While organisms like Heterotrophs utilse complex substances andbreak them down into simple substances. Thus the survival of heterotrophsdepends directly or indirectly on autotrophs.

The different modes of nutrition are :-

• Autotrophic mode of nutrition.• Heterotrophic mode of nutrition.



Photosynthesis is the process by which autotrophs like green plants and some

other organisms use sunlight in the presence of chlorophyll to synthesize foodsfrom carbon dioxide and water. The material taken in the form of carbon dioxideand water which is converted into carbohydrates in the presence of sunlight andchlorophyll. Carbohydrates are utilised for providing energy to the plant. Thecarbohydrates which are not used immediately are stored in the form of starch which serves as the internal energy reserve to be used as and when required by the plant.

ChlorophyllSunlight (Glucose)

The chemical formula of Photosynthesis is -

The following events occur during photosynthesis -

• absorption of light energy by chlorophyll.•Conversion of light energy to chemical energy andsplitting of water molecules into hydrogen and oxygen.

• Reduction of carbon dioxide to carbohydrates.



Heterotrophs utilise complex substances which are broken down into simpler ones before they can be

used for the upkeep of and growth of body. To achieve this, organisms use bio-catalysts calledenzymes. The heterotrophs survival depends directly or indirectly on autotrophs. Animals and fungi

are some examples of Heterotrophs. The form of nutrition differs depending on the type and availability of food material as well as how it isobtained by the organism. There is a range of strategies by which the food is taken in and used by theorganism. Some organisms like fungi like bread moulds, yeast and mushrooms break-down the foodmaterial outside and then absorb it. Others take in whole material and break it down inside theirbodies. Some other organisms derive from plants or animals without killing them. This parasiticnutritive strategy is used by a variety of organisms like lice, leeches and tape worms.

Types of Heterotrophic Nutrition

This type of nutrition involves the taking in of solid particles as food which have to be furtherbroken down into simpler particles inside theorganism. the food is first taken into the body through an opening called a mouth (ingestion),then it is converted into a simple and solubleform by various enzymes (digestion);simplified products formed are then absorbed(absorption); the conversion of nutrientinto the fluid or solid substance of the body (Assimilation); and finally the undigested part

of food is removed from the body (egestion).

http://en.wikipedia.org/wiki/Ingestion

http://en.wikipedia.org/wiki/Digestion

http://en.wikipedia.org/wiki/Absorption_(small_intestine)

http://en.wikipedia.org/wiki/Egestion

http://en.wikipedia.org/wiki/Egestion

http://en.wikipedia.org/wiki/Absorption_(small_intestine)

http://en.wikipedia.org/wiki/Digestion

http://en.wikipedia.org/wiki/Ingestion



Parasitic nutrition is a mode of nutrition where organism(known as a parasitic) lives on the body surface or inside thebody of another type of organism and obtains nutrition

directly from the body of the other organism (knownas a host). Since these parasites derive their nourishmentfrom their hosts, this symbiotic interaction is oftendescribed as harmful (to the subject of host). Most parasitesare so tiny in size and some are even invisible to the nakedeye of a human. Many parasites have complex life cyclesinvolving multiple hosts.

'sapros' refers to rotten and 'trophic' refers to food.

Saprotrophic nutrition is the process by which theorganisms feed on dead and decaying matter. Thefood is digested outside the cells or even outsidethe body of the organism which is known as extracellulardigestion. The organism secretes digestive juices, whichcontain enzymes, directly on to the food. Thedigestive juices makes the food soluble and it is

then absorbed by the organism through the body surface.



Mutualism a symbiotic relationship between organisms, with eachcontributing and benefiting from each other. A well known example

of mutualism is the relationship between cows and bacteria withintheir intestines. Cows benefit from the cellulase produced by thebacteria, which facilitates digestion; the bacteria benefit from havinga stable supply of nutrients in the host environment. The picture (Rt.) shows aHummingbird drinking from the flower. Pollination is a classic examplemutualism.

Amoeba takes in food using pseudopodia temporary finger-like extensionsof the cell surface which fuse over the food particleforming a food-vacuole (ingestion). Inside thefood vacuole, complex substances are brokendown into simpler ones (digestion) which thendiffuse into the cytoplasm (absorption +assimilation). The remaining undigested

material is moved to the surface of the cell andthrown out.

sym sci nutrition

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