1. Virus are non-cellular components without protoplasm.
2. Virus are inert outside living cells as chemical particles or non-living crystals.
3. They are not self-reproducing. Cannot multiply outside the cell.
4. They can be aliquoted, centrifuged, spread and suspended.
5. They do not have cell wall, plasma membrane, mitochondria, lysosomes, ribosomes etc.
6. Physical growth of the virus does not occur.
7. They do not respond to any environmental stimuli.
8. Physiological functions- photosynthesis, respiration, movement, growth, osmosis etc. do not take place.
9. They have no metabolic enzymes and no nutritional activity.
10. Antibiotics cannot cause any reaction in the body of the virus.
11. Virus can resist acids, alkalis and salts.
12. They have no energy producing system.
13. They do not increase in size and do not respond to any external stimuli.
14. They cannot be controlled by antibiotics.