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प्रश्न
Organise a discussion in your class on the topic- Are viruses living or non-living?
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उत्तर
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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संबंधित प्रश्न
Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.
Influenza is a _____ disease.
Complete the analogy.
Cholera : Bacteria :: Smallpox : _____
Mention any two viral diseases.
The infecting virus particle found outside the host cell is _______.
Female anopheles mosquito is a carrier of dengue virus.
Define the following.
Bacteriophages
Distinguish between Virion and Viroid.
______ is a cellular agent that replicates only inside the cells of the other living organism.
Complete the Analogy.
Polio: Virus:: Tetanus: ______.
What is a Retrovirus?
Viruses are non-cellular, ______ parasites.
Adenovirus is ______ virus.
Virions are the smallest among the infective agents.
Viruses are devoid of cellular organelles like ribosomes mitochondria, etc.
Influenza commonly occurs during adult age.
Contagium vivum fluidum was proposed by ______.
A virus is considered as a living organism and an obligate parasite when inside a host cell. But virus is not classified along with bacteria or fungi. What are the characters of virus that are similar to non-living objects?
