Science IA- Viruses
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- who discovered viruses?
- Dimitre Iwanoski
- when were viruses discovered?
- 1892
- How were viruses discovered?
- Iwanoski used a microfilter to remove tobacco mosaic viruses, then transferred it to other plants.
- What was the first virus worked with?
- the tobacco mosaic virus
- Did dimitre see the virus?
- no, he only saw its effects
- What is an important tool for the study of viruses?
- electron microscope
- how much can the electron microscope magnify up to?
- 1,000,000x
- what makes the electron microscope different from a regular microscope?
- it uses electrons instead of light.
- What are the three viral shapes?
- helical, icosahedral, and complex.
- What are the helical viruses' characteristics?
- they are cork-screwed or spring-shaped. they cause measles, rabies, and tobacco mosaic.
- What are the icosahedral viruses' characteristics?
- polyhedron shape with 20 triangular faces and 12 corners. causes herpes simplex, polio, and parvovirus
- what are the complex viruses' characteristics?
- combination of helical and icosahedral symmetry types. common diseases are bacteriophages, smallpox, and influenza.
- What are the two basic parts that all viruses consist of?
- genome and capsid
- What is a genome?
- a segment or entire pice of nucleic acids (DNA or RNA).
- What is a capsid?
- a code of protein around the virus that protects a genome.
- What is a capsid broken into?
- smaller protein molecules known as capsomeres.
- What does the number of capsomeres in a virus's capsid determine?
- it determines the shape of the virus for identification.
- What is a nucleocapsid?
- a capside plus a genome
- What is an envelope?
- a flexible membrane that covers the virus.
- What is an envelope made of?
- lipids and proteins.
- What are spikes?
- projections on the envelope.
- What do spikes contain?
- enzymes which help in the attachment to a host cell.
- What is a viron?
- a completely assembled virus outside a host cell.
- What is replication?
- making identical copies.
- What are bacteriophages?
- a type of virus that infects only bacteria.
- How many stages are in the process of replication?
- 5 stages
- What are the stages in the process of replication?
- attachment, penetration, biosynthesis, maturation, and release.
- What is attachment?
- the first step in replication. the virus attaches to the cell.
- What is penetration?
- the second step in replication. the genome enters the cell, while the capsid stays outside the cell.
- What is biosynthesis?
- the third step in replication. during it, the phage falls away and dies. it synthesizes new parts of a virus with proteins using ribosomes.
- What is maturation?
- the fourth step in replication. the virus matures and completes its assembly.
- What is release?
- the fifth step in replication. breaks open the cell to reinfect. destroys the host cell.
- What are pneumotropic viruses?
- viruses that affect the respiratory system.
- Which viruses affect the respiratory system?
- pneumotropic viruses.
- What are dermotropic viruses?
- viruses that affect the skin.
- Which viruses affect the skin?
- dermotropic viruses.
- What are viscerotropic viruses?
- viruses that affect the blood and organs.
- Which viruses affect the blood and organs?
- viscerotropic viruses.
- What are neurotropic viruses?
- viruses that affect the central nervous system.
- Which viruses affect the central nervous system?
- neurotropic viruses.
- What are some examples of DNA viruses?
- pox viruses, Hepatitis B, herpes, Epstein Barr virus.
- What are some examples of RNA viruses?
- Hepatitus A, polio, flu, rabies, HIV.
- what do vaccines do?
- they stimulate antibody production by the immune system for a defense to the virus.
- what are the two types of vaccines?
- inactivated virus vaccines and attentuated viral vaccines.
- What do inactivated virus vaccines do?
- live viruses are treated with physical agens such as mild heat, UV heat, chlorine, detergents, or formaldehyde. these agents alter the DNA or RNA, preventing the replication or parts of the new virus.
- what do attentuated viral vaccines do?
- they cause firuses to become less dangerous by re-culturing the virus for a long period of time.