NutritionNutrition

• Process by which organisms obtain and use the nutrients required for maintaining life

Modes of nutritionModes of nutrition• Ways of obtaining and using nutrients

Nutrition

Autotrophic nutrition

Heterotrophic nutrition

Holozoic nutrition

Saprophytic nutrition

Parasitic

nutrition

Autotrophic nutritionAutotrophic nutrition• make their own food

(complex organic substances) using simple inorganic substances– the organism

autotrophs• e.g. Green plants– by photosynthesis

Heterotrophic nutritionHeterotrophic nutrition

• depends on other organisms or dead organic matters as their food sources– the organism Heterotrophs

• Cannot make their own food and obtain their food in organic form

Autotrophic nutrition

•  PHOTOAUTOTROPHS Photosynthetic organisms are photoautotroph which means that they are repositories of energy, they are able to synthesize food directly from carbon dioxide, water, and using energy from light. 

 CHEMOAUTOTROPHSDeriving energy from chemical reactions, synthesize all necessary organic compounds from carbon dioxide. eg- bacteria

Other modes of nutrition in plants

• Parasitic

• Insectivorous

• Saprophitic

• symbiotic

Parasitic plants

Cuscuta growing on other plants

Insectivorous plants

Symbiotic plants

Lichens

Sybiosis- Leguminous plants

Saprophytic nutritionSaprophytic nutrition(Saprophytism)(Saprophytism)

• Organisms feed on dead organisms or non-living organic matter– Saprophytes

(e.g. fungi, bacteria)

How A Saprophyte How A Saprophyte Obtains Its Nutrients?Obtains Its Nutrients?

Example : Mucor & Rhizopus (bread mould)

• Hyphae release digestive enzyme into the bread

• Enzymes digest complex organic molecules in bread into simple, soluble molecules(extracellulardigestion )

• Digested products are absorbed by hyphae

Mass of hyphae = myceliumSporangium :

produces spores for reproduction

Importance of saprophytesImportance of saprophytes• As decomposers

–Allow essential materials (e.g. C, N) to be recycled in the ecosystem

Complex organic

substances

Simple soluble compounds

Enzyme from saprophytes

To observe Mucor

Why is it necessary to leave the moist bread uncovered for 30 minutes ?

Ans: Because the spore of Mucor are carried by air current. They can drop onto the bread and then germinate.

What are the thread-like structures growing on the surface of the bread ?

Ans: The thread-like structures are used for feeding. They are called hyphae which can produce enzymes for digesting the organic food.

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