life process  chapter 1 NUTRITION


All living things perform certain life processes like growth, excretion, respiration,
circulation etc.
The basic functions performed by living organisms for their survival and body
maintenance are called life process.
Basic life processes are : Nutrition, Respiration, Transportation, Excretion etc.
Life Processes require energy which is provided by nutrition.
Modes of Nutrition
1. Autotrophic :-Kind of nutrition in which organisms can synthesize their own food Eg.
Green Plants
2. Heterotrophic:- Kind of nutrition of which organisms do not possess the ability to
synthesize their own food. They depend on autotrophs for their food supply directly or
indirectly. Eg. Animals, Fungi
Autotrophic Nutrition
Autotrophs : The organisms which can make their own food are called autotrophs
(green plants).
Photosynthesis : The process by which green plants make their own food with the
help of CO and H O in the presence of chlorophyll and sunlight is also called
photosynthesis.
Raw Materials for Photosynthesis : CO2 and H20
Site of Photosynthesis : Chloroplast in the leaf. Chloroplast contain chlorophyll. (green
pigment)
Absorption of Sunlight energy by chlorophyll
 Co2 to carbohydrates.
Stomata : Tiny pores present on the surface of the leaves.
Functions of Stomata
(i) Exchange of gases
(ii) Loses large amount of water [water vapour] during transpiration and helps in up
flow of water
Chloroplast contains the green pigment chlorophyll which has a pivotal role in
photosynthesis.
Amoeba has a holozoic nutrition. Thus, solid food particles are ingested which react with
enzymes and are digested. It is an omnivore.
(i) Amoeba move with the help of pseudopodia (extension of cell membrane) 
ii) Food vacule is formed
(iii) Undigested food is thrown out.
Nutrition in Human Beings : The human digestive system comprises of alimentary
canal and associated digestive glands





HUMAN DIGESTIVE SYSTEM: As shown in the flow chart, digestion begins from th mouth.In
the mouth it is broken down by salivary amylase. The food moves to the stomach through the
oesophagus which performs persistatic movement. Enzymes and various digestion juices
from liver,gall bladder and pancreas act on the chunks from the stomach in the small
intestine. In the large intestine , the remaining nutrients are absorbed and the leftover is
removed from the body through the rectum and anus.
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