Russian pathologist who in 1892 worked with tobacco plants
Explain Dimitri's experiment
- Took diseased tobacco leaves and crushed them for juice
- Filtered the juice
- Put the juice on healthy leaves
What was the conclusion to Dimitri's experiment?
Healthy leaves became infected
What was Dimitri's hypothesis?
Plants were giving off a poision
Who, 6 years later performed the same experiment as Iwanowski?
What was Martinus Beijernick's hypothesis?
That plants had a virus (poison)
Who, in 1935 isolated the first virus which was the Tobacco Mosaic Virus
A non-cellular particle made of DNA/RNA and covered by a protein coat
Give 7 examples of a virus
- Common cold
- Cold Sores
What are the 5 steps to the Lytic Cycle Virus?
- 1. Attach to the surface of a cell
- 2. Invade- inject DNA or RNA into host cell
- 3. Replicate- while in the host cell new virus particles are made
- 4. Assembly-Virus parts are then put together
- 5. Lysis-The viruses burst out of the cell thus destroying the cell
Give 3 examples of the Lytic Cycle Virus
- Common Cold
- Stomach Virus
Something to remember about Lytic Cycle Virus?
That it's quick like the 24 hour flu or anything like that
How is Lytic different from Lysogenic?
Lysogenic goes dormant
What are the 3 Steps of Lysogenic Cycle Virus
- 1. Attach- virus attaches to the surface of the cell
- 2. Invade-inject DNA or RNA into the host cell
- 3. Dormancy-The viral DNA joins with the host DNA and stays dormant until stimulated
- 4. Once stimulated the virus enters the Lytic Cycle
4 Examples of Lysogenic Cycle Virus?
What triggers a dormant (lysogenic) virus to become active (lytic)?
- 1. Stress
- 2. UV Radiation
- 3. Extreme Cold/heat
- 4. Another sickness
What is true about a virus?
Once you have it it will never leave your body
What does Retrovirus contain as their genetic material?
What does Retrovirus produce?
A DNA copy of their RNA genes
How is genetic material copied in Retrovirus?
What is an example of Retrovirus?
Used to treat infections caused by bacteria
What can Antibiotics not treat?
Colds or Flu
Dead or weakened virus
How can you get a virus if your body already has the vaccine for it?
If your body is vulnerable, (stressed, already sick)
Is there a vaccine for AIDS?
Support why a Virus IS living
- Able to infect living cells
- Can grow, reproduce, regulate gene expression, and evolve
Support why a Virus IS NOT living
- Not made of cells
- Not able to live independently
In 1928, Who studied bacteria that caused pneumonia?
Explain Fredrick Griffith's experiment?
HE took 2 strains of bacteria:S strain (smooth) and R strain (rough).
He injected regular S strain into the mouse and the mouse got pnuemonia and died
He injected regular R strain into the mouse and it lived
Then he heated up the S strain and gave it to the mouse and the mouse lived.
- He heated the S strain Mixed it with the R strain
- He injected it into a rat
- The mouse died
- If the mouse would have only had the R strain it would have lived and not gotten pneumonia.
- The mouse died because the S strain caused Pneumonia.
- Griffith didn't know it back then, but what had changed the R cells into S was DNA.
- Scientists knew though that there was some type of disease causing ability that was transformed from 1 cell to another.
What DNA made up of?
- Deoxyribonucleic acid
- (sugar and phosphates)
Which of the following is neccessary for a virus to reproduce?
Living host cell
What are the 3 Key Roles of DNA
- Copying, and
- Transmitting Information
Contains genetic code for life.
"blueprints of life"
Who helped discover DNA in 1952 by x-ray crystallography?
What two people took Franklins' idea and discovered the structure of DNA and its components?
- James Watson
- Francis Crick
A natural vaccination happens when?
- When you get a lysogenic virus and then become immune to it.
- (When a person becomes immune to chicken pox after contracting it)
Viruses in the body are destroyed by what?
White blood cells
Where are viruses carried?
In the tissues
How are viruses spread between people?
- Contact with contaminated blood
- Insects that transmit infected blood
- Contact with saliva or mucus
Where is the nucleic acid housed in a virus?
What is nucleic acid?
What is the capsid?
What is one thing that won't cause a lysogenic virus to become lytic?
The process in which unharmful bacteria becomes harmful