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Question
Organise a discussion in your class on the topic- Are viruses living or non-living?
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Solution
Viruses are considered intermediaries between non-living substances and living organisms. It is quite difficult to determine if they are living or nonliving. Some virus traits imply a non-living nature, while others imply a living nature.
They resemble non-living objects in:
- Lacking protoplast.
- Ability to get crystallised.
- Inability to live independently of living cell.
- High specific gravity, which is found only in non-living objects.
- Absence of respiration.
- Absence of energy storing system.
- Absence of growth and division.
- Instead, different parts are synthesised separately.
Viruses resemble living beings in –
- Being formed of organic macromolecules, which occur only in living beings.
- Presence of genetic material.
- Ability to multiply or reproduce, although only inside living cell.
- Occurrence of mutations.
- The occurrence of enzyme transcriptase in most viruses.
- Some viruses, like the Pox virus, contain vitamins like riboflavin and biotin.
- Infectivity and host specificity.
- Viruses are ‘killed’ by autoclaving and ultraviolet rays.
- They breed true to their type. Even variations are inheritable.
- They take over the biosynthetic machinery of the host cell and produce the chemicals required for their multiplication.
- Viruses are responsible for a number of infectious’ diseases like the common cold, epidemic influenza, and chicken pox.
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