Q: How small can a virus get?
A: The tiniest viruses are only 20 nm in diameter-smaller than a ribosome.
Q: How do viruses identify host cells?
A: They do so by a "lock-and-key" fit between viral surface proteins and specific receptor molecules on the outside of cells.
Q: What is a phage that reproduces only by a lytic cycle called?
A: a virulent phage
1. A virus consists of a nucleic acid surrounded by a protein coat.
2. Viruses reproduce only in host cells.
3. Viruses, viroids, and prions are formidable pathogens in animals and plats.
4. The RNA animal viruses with the most complicated reproductive cycles are the retroviruses.
5. Viruses that appear suddenly or are new to medical scientists are often referred to as imerging viruses.
Viral infection of plants:
More than 2,000 types of viral diseases of plants are known, and there are a lot of annual loss worldwide due to their destruction of agriculture, etc. Common signs of viral infection include bleached or brown spots on leaves and fruits, stunted growth, and damaged flowers or roots, all tending to diminish the yield and quality of crops.
Viruses are particles of nucleic acid, protein, and, in some cases, lipids. All viruses have one thing in common: They enter living cells and, once inside, use the machinery of the infected cell to produce more viruses. Viruses are parasites, not considered to be living things because they are not made up of cells. Once the virus is inside a host cell, two different processes may occur and they are lytic infection and lysogenic infection.
There are viruses that cause diseases and they are called as pathogens.
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