What is a virus?
- Its a protein coded with dna
- Anti viral ( cant be treated by antibiotics)
What are the viral characteristics?
- Cant move
- Cant respond to stimuli
- Cant develop (grow)
- Contain complex components
- Can die ( by being destroyed )
Why are viruses NOT alive?
- Not made of cells
- No metabolism
- Cant reproduce within a host to kill it
- No homeostaisis
Why arent viruses alive?
They dont have all the fundamental characteristics of life. they must rely on other living things
What are viruses?
- Small, infectious, non living, non cellular particles
- Contain no cytoplasm
- Cannot grow or reproduce on their own (need a host)
- Do not produce or use energy
- Do not create waste
- Does have genetic material which controls other cells to create virus copies
Whats a virion?
A virus particle
Whats the basic structure of a viron?
Genetic material and the capsid ( or head)
What does the genetic material contain?
RNA (Single stranded) or DNA ( a double stranded core)
What is the capsid?
A protein coat that surrounds and protects the genetic material
What do RNA viruses look like?
- Usually single stranded RNA ( ribonucleic acid)
- Very high mutation rates due to not being proof read the same as DNA in replication
- Vaccines are not as effective due to mutations
What are examples of RNA viruses?
HIV, influenza viruses, rabies, measles, mumps, pneumonia, common cold, coronavirus
What do DNA viruses look like?
- Has double stranded DNA ( deoxyribonucleic acid)
- Lower mutation rates because of proofreading
- More constant/stable so vaccines are effective
What are examples of DNA viruses?
Chickenpox, cold sores, genital herpes, hepatitis, (respiratory infections, tumors)
What are the common virus shapes?
- Helical
- Polyhedral
- Complex
- Bacteriophage
What does the helical virus shape look like?
Theyre rod like with capsid protiens winding around the core in a spiral
Whats an example of a helical virus?
Tobacco mosaic virus
What does a plyhedral virus look like?
- Has many sides
- Most polyhedral capsids have 20 sides and 12 corners
Whats an example of a polyhedral virus?
Adenovirus ( causes respiratory infections, diarrhea, pink eye)
What does a complex virus look like?
Its a polyhedral capsid attached to a helical tail
- The tail is made of protein which helps binding yo host cells
What does bacteriophage look like?
Typically takes the shape of complex viruses
What does bacteriophage do?
- Infects by injecting DNA into a bacterium
- Once DNA joins the bacterial DNA the lysogenic cycle begins
Where does corona viruses get its shape from?
It gets the name from their shape which are round viruses surrounded by a sphere of spiky proteins
What are the 2 most deadly types of corona viruses?
SARS and MERS
What is the lytic cycle (AKA infectious cycle) ?
When a virus enters a cell, replicates itself hundreds of times, then bursts out of the cell destroying it
