Life processes Notes Biology (Class 10)

 LIFE PROCESS

Ø  The basic functions performed by living organisms in order to maintain their life on the earth is called life process.

For example :- Nutrition, Excreation, Respiration, Movement, Control & Co-ordination, Reproduction etc.

                                                                                                                                               

                NUTRITION

1.  It  is the way of getting or obtaining food by the organism.

2.   It is important to grow, develop, synthesise protein and other substance needed in our body.

There are two types of Nutrition:-

1.  Auto tropic Nutrition:- The Nutrition in which organism make their own simple food materials obtained from inorganic sources in the form of carbon dioxide, water and some other compounds.

  For example:- Nutrition in plants and some bacteria.

NUTRITION IN PLANTS

In plants, Nutrition takes place by the process of photosynthesis.

PHOTOSYNTHESIS:-  It is an process in which green plants manufacture carbohydrate from inorganic molecules like Co₂ and H₂O in the presence of sunlight.

6CO₂+12H₂OC₆H₁₂O₆+2H₂O+6O₂

Event that occur during the process of Photosynthesis are:-

1.  Absorption of light energy by chlorophyll.

2.  Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.

3.  Reduction of carbondioxide to carbohydrates.

Note:- These steps need not take place one after the other immediately.

For example :- In carbondioxide is taken at night and prepare an intermidiate which is acted upon by the energy absorbed by the chlorophyll during the day.

Ø Chlorophyll :- Most important pigment which traps solar energy and convert into chemical energy.

Ø Basically it is of seven types:-
                       ·      Chlorophyll A to E

·      Bacteriophyll

·      Bacterial Vidin
--->Cholorophyll A is responsible for the transformation of solar energy into chemical.

Ø Remain types absorbs solar energy and gives to chlorophyll A.

Formulla of chlorophyll A--

C₅₅ H₁₂ O N₄ Mg₅

Ø Due to the persence of Mg, leaves of plant look like green.

Ø Other pigments of plants are

·      Xanthrophyll -- Yellow

·      Carotence (carotenoides)-- Red

Ø In leaves, photosynthesis occures in measophyll area.

          Fig:-Crossectional view of a leaf.

Mechanism of Photosynthesis

1.  Opening and closing of Stomata

2.  Exchange of gases

Stomata :- These are the tiny pores present on the surface of leaves.

In nerbaceous plants, stomata are also present on the steam.

Each stoma (pl.stomata) is surrounded by two guard cells contains cholorophyllast and Nucleous.

1.  Opening and closing of stomata opening of Stomata:-  Stomata opens during day time towards inwards directions.

2.  In day time enough glucose formed through photosynthesis is converted into starch which is insoluble.  So, the guard cells absorbs excess water from surrounding cells and became turgid.

3.  Due to turgidity of gardcells, stomata opens.

CLOSING OF STOMATA

1.  Stomata remains close at night.

2.  At night when no photosynthesis occurs the starch is converted into Glucose.

3.  Due to which the osmotic concertration increases resulting exoosmosis of guard cells.

4.  This leds to shrinkage of guard cells and stomata gets closed.

Note:- Stomata remains close during day time also when atmospheric temperature exceeds more that 35⁰ to 40⁰ c.  At night minute stomata pore remains opens for respiration.

Exchange of gases:- The gases exchange in plants takes place through stomata by the process of diffusion.

The net exchange of gas during day time is co ₂  to o₂ and during night is o₂ to co₂.

      Bacterial Nutrition

                 or,

Chemosynthesis

                or,

Bacterial photosynthesis

It is a process which occur.  In bacterial cells.  In this process certain bacteria like chlorobium, sulphur bacteria etc .  Manufacture carbohydrate in the persence of sunlight from co₂ & other chemical instead of water.

In chemosynthesis No, oxygen gas is rebased as by produced.

6co2+12H₂S :--> C₆H₁₂O₆+I2S +12H₂0

Heterotropic Nutrition

The nutrition in which organism obtain their food from autotrops or any other organism,

They may be saprophytes, symbiotic, sapozoic, or parasitic or Holozoic.

Paracytism:-  It is a type of nutrition in which any organism get their food from other hosts are called paracytism.

eg:- Cascuta, Bladder Worst, Mosquitoes, leech etc,.

Saprophytic Nutrition :-  In this type of nutrition the plants obtain food from dead and decaying organic matter.

eg:- Aspergillus, Mushroom etc.

Symbiotic Nutrition :- A neterotropic mode of nutrition in which two different organism like together closely for getting mutual benefit called symbiotic.

Holozolic Nutrition  :- The mode of nutrition in which organism take  solid food is called holozoic nutrition.

eg:- Amoeba, Human beings, all the animals etc.

Phases of Holozoic Nutrition

Holozoic nutrition completes into 5 steps-

1.  Ingestion :- Intake of food in mouth.

2.  Digestion :- Breaking down of complex food molecule into simple and soluble forms by the action of various enzymes is called digestion. It is a Catabolic  process.

Note :- Enzyme are bio-catalystist used by organism for breaking of complex substance into simple ones.

Absorption :- It is the process in which digested food molecules are absorbed.

Assimilation :- The utilization of absorbed food molecules to recognised the complex.  organic molecules is called absorbtion.

It is an annobolic process.

Egestion :- The removal of undigested food and unabsorbed food out from body in the form of stool or faeces also called egestion.

Nutrition in Amoeba

Amoeba takes in food using temporary finger like extension of the cell surface which fuse over food particle forming a food vacuole.

Inside the food vacoule, complex substance are broken down into simpler ones which then diffuse into cytoplasm.  The remaining undigested food material is moved to the surface of cell and thrown out. In paramecium which is also a unicallar organism the cell has a difnite shape and food is taken in at a specific spot.  Food is moved to this spot by the movement of cilia which cover the entire surface of the cell.

Nutrition In Human Beings

1.  Igestion :- In this step, food is taken into the mouth.

2.  Digestion :- A catabolic process in which complex food molecules are broken down into simple soluble form by the action of various digestive enzyme is called Digestion.

In human extracellular digestion takes place.

Site of Digestion :-

1.  Buccal digestion :- In the mouth just after ingestion.  In mouth physical and chemical digestion takes place.

·      Physical digestion :- Refers to mestication (changing) of food.

·      Chemical digestion :- Occures during mestication when chewed food mixed with salvia where staren is converted into sugar through salivary amylase.

About 30% of digestive takes place into mouth.

After buccal digestion, food goes to stomach for gastric digestion by the process of peristalsis through oesophagus.

2.  Gastric digestion :- It occurs in stomach.

·      In stomach it wall release gastric juice which contains Hcl(0.04), water, Mucus, Pepsin, Renin etc.

·      Hydrochloric acid of gastric acid kills the pathogens present in food and also makes food acidic for protein digestion.

·      Pepsin is a protein digestive enzyme which secreated in the form of inactive pepsinogen Renin converts milk casein into calcium paracasein.

·      In the stomach partly digested food mixed with water of gastric juice and becomes watery called enzyme.

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