6. LIFE PROCESSES
Organisms show many properties such as movement (growth-related or not). But the visible movement is not a defining characteristic of life because a plant may not grow visibly and some animals can breathe without visible movement.
Viruses do not show any molecular movement in them until they
infect some cells.
Living organisms are well-organised structures having tissues,
cells, cell organelles etc.
Due to the effects of the environment, living structures may
be broken down and dead. So they must be repaired.
Since these structures are made up of molecules, they
must always move molecules around.
WHAT ARE
LIFE PROCESSES?
Life processes are all the maintenance processes to prevent damage and break-down of the body of an organism. E.g. nutrition, respiration, excretion, growth etc.
For this, energy is needed from the outside. This energy source is called food.
Since life depends on carbon-based molecules, most of the
food sources are carbon-based.
Foods are broken down or built up in the body. They are
finally converted to a uniform source of energy (for molecular movements) &
molecules for growth and development.
Oxidising-reducing reactions are some of the
most common chemical means to break down molecules. For this, many organisms
use oxygen.
In cells, various chemical reactions create useless and harmful
by-products. These are removed from the body by a process called excretion.
In unicellular organisms, the entire surface is in
contact with the environment. So, no specific organs are needed for food intake,
gas exchange or removal of wastes.
In multicellular organisms, all cells are not in contact
with the environment. So, simple diffusion will not meet the requirements of all
the cells. That’s why they have specialised body parts to perform various
functions.
A transportation system is needed to carry food
& oxygen to all body parts and waste products from tissues to excretory
system.
Select Your Next Topic 👇
👉 Part 1: What are Life Processes?
👉 Part 2: Nutrition
👉 Part 3: Respiration
👉 Part 4: Transportation
👉 Part 5: Excretion
