Explain the whole chapter life processes .
Answers
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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 Equation-����������������
� Autotrophic nutrition
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
(ii) Water
(iii) �Light
(iv) Temperature
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