Creative Teens' Club

LIFE PROCESSES

1.) Life – An organism is said to have life if it is performing all the metabolic activities means they can Grow, Reproduce, respire etc.

2.) Catalysts are substances that increase the rate of reaction of reactants without affecting the product.

3.) Enzymes are Biological Catalysts present in organisms, they are basically Proteins in nature. Uses - They help in altering rate of reaction either forward or backward. They help in conducting Metabolic Activities.

Metabolic Activities –

I.) NUTRITION

Nutrition is a process in which a organism intakes food and utilizes it for its growth and Development.

Food à Simple Compounds

(involves Oxidation and Reduction Reaction)

II.) RESPIRATION

Exchange of Gases takes Place.

III.) CIRCULATION/TRANSPORTATION

IV.) EXCRETION

MODE OF NUTRITION :-

I.) Autotrophic Nutrition

Organisms which can synthesize its food with the help of Photosynthesis

CO2 + H2O {light}à C6H12O6 + Energy + O2

Such Autotrophes which synthesis their food from Light are also called Photo-Autotrophes. The range of wavelength of length which helps in Photosynthesis is 400 nm – 700 nm

Photosythesis is the process in which the raw material like CO2 and Water are converted to food i.e. Glucose in presence of Sunlight and Chlorophyll.

Some Bacteria are also autotrophes but they don’t prepare their food from Light but from Complex Chemical Compounds, they are called Chemo-Autotrophes. Ex. Sulphur Bacteria,

Complex Compounds à {Energy is Released} Simple Compounds

The Glucose is stored in the form of Starch.

II.) Heterotrophic Nutrition

Heterotrophic nutrition can be defined as a type of nutrition in which energy is derived from the organic substances that are obtained from plants or animals. The organic substances after intake are first digested into simple forms, then are utilised by the organism.

Starch {Digestion} àC6H12O6 Stored as Glycogen

a. Holozoic Nutrition

b. Saprophytic Nutrition

In Organisms feeding on dead and decaying matter. E.g. Fungi

c. Parasitic Nutrition

In Organisms feeding on other living organisms. Absorb nutrition without killing organism. eg, Leech, flatworm.

Difference between Autotrophs and Heterotrophs.

Parameter

Autotrophs

Heterotrophs

Mode of obtaining food

Synthesise organic material using simple inorganic material.

Obtain organic food and digest it into simple inorganic material.

Types of organism

Producers

Consumers or decomposers

Examples

Green plants and autotrophic bacteria

All animals, fungi and bacteria (non-autotrophic).

PHOTOSYNTHESIS IN PLANT LEAF

Step 1 – Chlorophyll will absorb light and convert light energy into chemical energy.

Step 2 – Splitting of water molecule. 2H2O à 4H+ + O2+ + 4e- in thylakoids

Step 3 – Reduction of CO2 to Carbohydrates C6H12O6 takes place.

Photosynthesis is maximum in Red and blue light, no photosynthesis in Green light, as green coloured Chloroplast reflect the Green light so no light is absorbed.

Stomata are the site for exchange of gases. The Pore in the centre is called stoma pore, present on Epidermis. Guard Cell – Regulate Opening and Closing of Stoma.