CBSE Biology 10th key notes

Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc.

Criteria of life - (i) Growth  (ii) Movement

Nutrition - The process of taking  in food and its utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body is called Nutrition.

Types of nutrition   

                                                                        

1.      Autotrophic nutrition(Auto =self:  trophos = nourishment) E.g. Plants, Algae,blue green bacteria.

 Process – Photosynthesis (Photo=light; Synthesis= to combine)

Raw materials- (i) Carbon dioxide (ii)Water


Chlorophyll Formula :  C55H72O5N4Mg
Equation-  6CO₂  +  6H₂O             sunlight /    Chlorophyl  ----->      C₆H₁₂O₆      +     6O₂ 

Energy Conservation  Light/Solar energy to Chemical energy

Role off Chlorophyll- To trap the sun’s energy for photosynthesis

Factors- (i) Carbon dioxide (ii) Water(iii) Light (iv) Temperature

Events/ Steps of photosynthesis-  

(i) Absorption of light energy by chlorophyll

(ii) Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen & oxygen

(iii) Reduction of Carbon dioxide to Carbohydrate

Gaseous exchange- (i) Gas used- Carbon dioxide (ii) By product - Oxygen

Source of raw materials-

(i)         Carbon dioxide –Land plants- Air, Aquatic plants- Water

     (ii)      Water & Minerals - Soil

2.      Heterotrophic nutrition (Hetero =others:  trophos = nourishment) Eg. Animals, plants lacking chlorophyll like fungi.

(a)    Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.g. Fungi, Bacteria

(b) Parasitic nutrition: Organisms obtain food from the body of another living (host)

Endoparasite :  Parasites lives inside the body of the host e.g. tapeworm, roundworm.

Exoparasite:  Parasite lives on the body of the host. E.g. lice, leech.

Note - The parasite benefits while the host is usually harmed e.g. Cuscutta-plant parasite(amar bel), plasmodium (malarial parasite).

(c) Holozoic nutrition: Organism (mostly animals) take in whole food and then digest it into smaller particles with enzyme. Eg. Amoeba, Paramecium. Animals, human beings.

 Steps in Holozoic nutrition

(i)               Ingestion  taking in of food.

(ii)               Digestion: breaking down of complex food into simpler, absorbable form.