2. various function carried out by living being; which are
necessary to maintain and continue life are called life
processes.
Main features of life processes-
1.nutrition
2.respiration
3.transportation
4.excretion
5.movement
6.reproduction
3. The process of taking in food and utilizing
it is called nutrition.
The term ‘nutrition’ comes from the word
‘nutrient’.
A nutrient is an organic or inorganic
substance required for the maintenance of
life and survival of a living organism.
The food taken in by an organism contains
a large number of nutrients like
carbohydrates, fats, proteins
5. The word ‘auto’ means ‘self’ and ‘trophe’
means ‘nutrition’.
Autotrophic nutrition is that mode of nutrition
in which an organism makes its own food
from the simple organic materials like carbon
dioxide and water present in the surroundings
(with the help of sunlight energy)
Those organisms which can make their own
food from carbon dioxide and water are called
autotrophs.
6. Green plant are autotrophs and synthesis their
own food by the process of photosynthesis.
‘Photo’ means light and ‘synthesis’ means build,
thus photosynthesis means ‘build up by light’.
The process by which green plants make their own
food from carbon dioxide and water by using
sunlight energy in the presence of chlorophyll is
called photosynthesis.
Raw material required are carbon dioxide and
water.
Oxygen gas is released during photosynthesis
7. 6CO2 + 6H2O + Light Energy ---- C6H12O6 + 6CO2
The process of photosynthesis takes place in the green
leaves of a plant.
The food prepared by the green leaves of a plant is in the
form of a simple sugar called glucose.
The extra glucose is changed into another food called starch.
The green plants convert sunlight energy into chemical
energy by making carbohydrates (food).
Site of photosynthesis is Chloroplasts.
8. The photosynthesis takes place in the following
four steps :
1. Absorption of sunlight energy by chlorophyll.
2. Conversion of light energy into chemical
energy.
3. Splitting of water molecules into hydrogen
and oxygen by light energy.
4. Reduction of carbon dioxide to form
carbohydrates like glucose by utilising the
chemical energy
10. The word ‘heteros’ means other and ‘trophe’
means nutrition, thus heterotrophic means
nutrition obtained from others.
All animals have a heterotrophic mode of
nutrition.
Those organisms which cannot make their
own food from inorganic substance like
carbon dioxide and water depend on other
organism for their food are called autotrophs.
11. Saprophytic nutrients…….
Saprophytic nutrition is that nutrition in which an organism obtains its
food from decaying organic matter of dead plants, dead animals, and
rotten bread, etc.
Parasitic nutrients……
The parasitic nutrition is that nutrition in which an organism derives its
food from the body of another living organism (called its host) without
killing it.
holozoic nutrients…….
The holozoic nutrition is that nutrition in which an organism
takes the complex organic food material into its body by the
process of ingestion, the ingested food is digested and then
absorbed into the body cells of the organism.
12. The nutrition in human beings takes place
through human digestive system
The human digestive system consists of the
alimentary canal and its associated glands.
The various organs of the human digestive
system in sequence: Mouth, Oesophagus,
Stomach, Small Intestine, and Large
Intestine.
The glands which are associated with the
human digestive system and form a part of
the human digestive system are: Salivary
Glands, Liver, and Pancreas.
13.
14. The process of releasing energy from food is
called respiration.
The process of respiration involves taking in
oxygen into the cells, using it for releasing
energy by burning food, and the eliminating
the waste products from the body.
Food + Oxygen ----- Carbon Dioxide + Water
+ Energy
Respiration is essential for life because it
provides energy for carrying out all the life
processes which are necessary to keep the
organisms alive.