Life process complete nots, Schemes and Mind Maps of Environmental science

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LIFE PROCESSES

LIFE PROCESSES

The processes in which living organisms perform maintenance functions are called life processes.

NUTRITION

The process of obtaining energy through

consumption of food is called nutrition.

Although the basic need for food is common to all organisms, the way they obtain it differs. Based on this, organisms are classified into two main types 1.Autotrophic 2.heterotrophic

1. AUTOTROPHIC NUTRITION

The mode of nutrition in which an organism prepares its

own food is called autotrophic nutrition.

Green plants and blue-green algae are examples

of autotrophs.

Main Events in Photosynthesis

• Absorption of light energy by chlorophyll.
• Conversion of light energy to chemical energy
• splitting of water molecules into hydrogen and oxygen.
• Reduction of carbon dioxide to carbohydrates. Carbohydrates thus produced are utilised for providing energy to the plant. The carbohydrates which are not used immediately are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant

PHOTOSYNTHESIS IN DESERT PLANTS

Desert plants take up carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day

CROSS SECTION OF LEAF LAMINA

CHLOROPLASTS

The green dots in leaf cells that contain

chlorophyll are called chloroplasts. They

are the sites where

photosynthesis occurs.

Function of Stomata

a) Exchange of gases (O2 /CO2 ). b) Loses large amount of water (water vapour) during transpiration.

Guard cells

The bean shaped cells on either side of stomata are called guard cells.

FUNCTION OF GUARD CELLS

The function of guard cells is to regulate the opening and

closing of the stomatal pore.

The guard cells swell when water flows into them, causing

the stomatal pore to open. the pore closes if the guard

cells shrink.

HETEROTROPHIC NUTRITION

The type of nutrition in which organisms are dependent on other organisms for their food requirements is called heterotrophic nutrition. Ex: Animals, fungi and bacteria there are three types they are Saprophytes Organisms that break-down the food materials outside the body and then absorb it are called saprophytes. Ex: Fungi like bread moulds, yeast and mushrooms.

Holozoic nutrition

The type of nutrition in which organisms take in whole material and break it down inside their body

is called holozoic nutrition.

Parasitic nutrition

The type of nutrition in which organisms derive nutrition from plants and animals without killing them is called parasitic nutrition. Ex: Cuscuta, orchids, ticks, lice, leeches and tape-worms.

NUTRITION IN PARAMECIUM

In Paramecium, which is a

unicellular organism, the cell

has a definite shape and

food is taken in at a specific

spot. Food is moved to

this spot by the movement

of cilia which cover the

entire surface of the cell.

NUTRITION IN HUMAN BEINGS:

Mouth:  The process of digestion starts here.  Teeth chew the food to break it into smaller pieces.  Salivary glands release saliva. The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar