Write your text here!➣ 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 in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. And excretes the waste materials from the body
Types of nutrition
1. Autotrophic nutrition (Auto =self: trophos = nourishment) E.G. Plants, Algae, blue green bacteria.
o Process – Photosynthesis (Photo=light; Synthesis= to combine)
o Raw materials- (i) Carbon dioxide (ii)Water
o Energy conversion- Light/Solar energy to Chemical energy
o Role off Chlorophyll- To trap the sun‘s energy for photosynthesis
o Factors for Autotrophic nutrition -
(i) Carbon dioxide
o 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
o Gaseous exchange-
(i) Gas used- Carbon dioxide
(ii) By product - Oxygen
o Source of raw materials-
(i) Carbon dioxide –Land plants- Air, Aquatic plants- Water
(ii) Water & Minerals - Soil
2. Heterotrophic nutrition (Hetero =others: trophos =ourishment) Eg. Animals, plants lacking chlorophyll like fungi.
(a) Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.G. Fungi, Bacteri
(b) Parasitic nutrition: Organisms obtain food from the body of another living (host)
o Endoparasite : Parasite lives inside the body of the host e.G. Tapeworm, roundworm.
o 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, Paramoecium. Animals, human beings.
o Steps in Holozoic nutrition
(i) Ingestion: taking in of food.
(ii) Digestion: breaking down of complex food into simpler, absorbable form.
(iii Assimilation: Utilization of digested food from the body.
(iv)Egestion: Removing undigested food from the body
o Nutrition in human beings
Mouth Oesophagus Stomach Small intestine Large intestine
o Some common features of Respiratory organs-
(i) Large surface area- for greater rate of diffusion of respiratory gases.
(ii) Thin permeable walls – to ensure easy diffusion & exchange of gases.
(iii) Extensive blood supply- Respiratory organs are richly supplied with blood vessels for quick transport of gases.