endoplasmic reticulum, golgi bodies and so on (Example: Bacteria and Blue green algae). In Eukaryotes a definite nucleus and membrane bound organelles are present. Eukaryotes may be unicellular ( Amoeba ) or multicellular ( Oedogonium ). Atoms Mixture Molecules & Compounds Crystals Organelles Colloids Living cells Tissues Organs Organ systems Individual organism Population Community Ecosystem Biosphere Non Living Living Ecosystem Individual organism Living cells I II III Figure .
: The levels of organization and integration in living organism Activity . Collect Vallisneria leaves or Chara from nearby aquarium and observe a leaf or Chara thallus (internodal region)under the microscope. You could see cells clearly under the microscope. Could you notice the movement of cytoplasm?
The movement of cytoplasm is called cytoplasmic streaming or cyclosis . . Viruses Did you go through the headlines of newspapers in recent times? Have you heard of the terms EBOLA, ZIKA, AIDS, SARS, H1N1 etc.?
There are serious entities which are considered as “Biological Puzzle” and cause disease in man. They are called viruses. We have learnt about the attributes of living world in the previous chapter. Now we shall discuss about viruses which connect the living and nonliving world.
their surroundings by sense organs. This is called Consciousness . Plants also respond to the stimuli. Bending of plants towards sunlight, the closure of leaves in touch-me-not plant to touch are some examples for response to stimuli in plants.
This type of response is called Irritability. Homeostasis Property of self-regulation and tendency to maintain a steady state within an external environment which is liable to change is called Homeostasis . It is essential for the living organism to maintain internal condition to survive in the environment. Metabolism The sum of all the chemical reactions taking place in a cell of living organism is called metabolism .
It is broadly divided into anabolism and catabolism. The difference between anabolism and catabolism is given in Table . . Table .
: Difference between anabolism and catabolism Anabolism Catabolism Building up process Breaking down process Smaller molecules combine together to form larger molecule Larger