Virus diseases
A virus can do nothing by itself, yet inside a host cell it becomes a disease.
Plant virus diseases
- Chilli leaf curl
- Banana bunchy top
Animal virus diseases
- Dengue
- The common cold
- Influenza
- AIDS
Being informed about virus diseases matters a great deal for avoiding them. Because a virus cannot live on its own, blocking the route by which it spreads is enough to stop it.
Glossary
| Cellular organization | සෛලීය සංවිධානය |
| Nutrition | පෝෂණය |
| Respiration | ශ්වසනය |
| Reproduction | ප්රජනනය |
| Movement | චලනය |
| Excretion | බහිස්ස්රාවය |
| Sensitivity | සංවේදිතාව |
| Irritability | උද්දීප්යතාව |
| Co-ordination | සමායෝජනය |
| Growth & Development | වර්ධනය හා විකසනය |
| Auxanometer | වෘද්ධිමානය |
Chapter summary
- Cellular organization, nutrition, respiration, irritability and co-ordination, excretion, movement, reproduction, and growth and development can be taken as the characteristics of living organisms.
- The basic level of organization of an organism is the cell. In a multicellular organism a complex organization at tissue, organ and system level is found.
- Nutrition is the process of obtaining energy and materials to maintain life; cellular respiration is the production of energy from that food inside the cells.
- Irritability is the ability to respond to stimuli; co-ordination is the process of adjusting the body's activity to suit those responses.
- Excretion is the process of removing metabolic waste from the body; organisms move as a result of co-ordination.
- Reproduction is the process of producing a new generation. Cell growth is an irreversible increase in dry weight; in development cells specialise for a particular job.
- A virus is a non-cellular form that cannot be sorted cleanly into living or non-living.
- All living organisms contribute to the survival and the balance of the environment.