Life is a unique, complex organization of molecules, expressing through
chemical reactions which lead to growth, development, responsiveness,
adaptation and reproduction.
Life is a characteristic quality that differentiates inanimate (non-living)
objects from the animate (living) forms.
PROPERTIES OF LIVING ORGANISMS
1. Growth
1. It is the increase in mass and number of cells.
2. In plants, growth by cell division occurs continuously throughout their
life span.
3. In animals, growth is only up to a certain age. However, cell division
occurs in certain tissues to replace lost cells.
4. Non-living objects grow by accumulation of material on the surface. In
living organisms, growth is from inside.
2. Reproduction
1. It is the production of progeny similar to those of parents.
2. Organisms reproduce asexually and sexually.
3. Growth is the increase in cell number or mass. Hence in unicellular
organisms, growth and reproduction are same.
4. Many organisms do not reproduce (e.g. mules, worker bees, infertile
human couples, etc). Hence, reproduction is not a perfect defining
characteristic of living organisms.
3. Metabolism
1. It is the sum total of all biochemical reactions taking place inside a
living system.
2. Isolated metabolic reactions in vitro are not living things but are living
reactions.
4. Cellular organization
1. All living organisms are made up of cells. They may be unicellular
(single celled organism) or multicellular (multi celled organism).
chemical reactions which lead to growth, development, responsiveness,
adaptation and reproduction.
Life is a characteristic quality that differentiates inanimate (non-living)
objects from the animate (living) forms.
PROPERTIES OF LIVING ORGANISMS
1. Growth
1. It is the increase in mass and number of cells.
2. In plants, growth by cell division occurs continuously throughout their
life span.
3. In animals, growth is only up to a certain age. However, cell division
occurs in certain tissues to replace lost cells.
4. Non-living objects grow by accumulation of material on the surface. In
living organisms, growth is from inside.
2. Reproduction
1. It is the production of progeny similar to those of parents.
2. Organisms reproduce asexually and sexually.
3. Growth is the increase in cell number or mass. Hence in unicellular
organisms, growth and reproduction are same.
4. Many organisms do not reproduce (e.g. mules, worker bees, infertile
human couples, etc). Hence, reproduction is not a perfect defining
characteristic of living organisms.
3. Metabolism
1. It is the sum total of all biochemical reactions taking place inside a
living system.
2. Isolated metabolic reactions in vitro are not living things but are living
reactions.
4. Cellular organization
1. All living organisms are made up of cells. They may be unicellular
(single celled organism) or multicellular (multi celled organism).
