1. VIRUSES
DEFINITION – nonliving infectious particle that lives in a host cell.
A. HISTORY
1. DISCOVERY – tobacco mosaic virus
2. SIZE - animation
3. ORIGIN – pieces of DNA/RNA escaped from cells and then go back and infect these same cells.

2. Why are viruses considered nonliving?
Characteristics of life????
Cannot –
Make food
Take in food
Use energy
Respond to stimuli
Make waste
Reproduce on their own (must be in a host cell)

3. B. STRUCTURE
1. PROTEIN COAT 2. CORE – either DNA or RNA

4. Bacteriophage Virus – a virus that infects bacteria

5. 3. SHAPE – GEOMETRICAL
4. SPECIFICITY – ONLY ATTACK CERTAIN CELLS

6. Lytic cycle – virulent viruses Lysogenic cycle – temperate viruses
Viral Reproduction
Lytic cycle – virulent viruses
Lysogenic cycle – temperate viruses

7. C. REPRODUCTION 1. LYTIC CYCLE – a. ATTACHMENT b. ENTRY c. REPLICATION
Ex. Cold, flu, measles
a. ATTACHMENT
b. ENTRY
c. REPLICATION
d. ASSEMBLY
e. RELEASE

8. 2. LYSOGENIC CYCLE ex. HIV, warts, chicken pox/shingles
A. ATTACHMENT
B. ENTRY
C. PROVIRUS IS FORMED
VIRUS POPS OUT OF HOST CELL DNA
D. REPLICATION
E. ASSEMBLY
F. RELEASE

9. Animation of lytic/lysogenic cycle
Review of virus notes

10. D. OTHER TYPES OF VIRUSES
RETROVIRUS- contains RNA and transcriptase – which takes over the DNA to make RNA to make new viruses

11. 2. Prions Made only of proteins -
which cause neurological diseases such as:
Alzheimer's disease
Creutzfeldt-Jakob disease (Mad Cow)
Kuru

12. 3. Viroids
Made only of Rna and occur in plants

13. How do communicable diseases spread?

14. E. SPREADING OF INFECTIOUS DISEASES
DIRECT CONTACT
a) touching
b) hugging, kissing
c) sex
INDIRECT CONTACT
a) inhalation of droplets
b) contact with infected blood
c) sharing needles
d) contact with contaminated object
e) drinking after someone
f) contaminated food or water
g) animal bites

15. Treatments for viral diseases
Prevention: Vaccinations
Antiviral drugs
Immune system – antibodies – which are proteins that target foreign materials in a cell Leukocytes – white blood cells that engulf disease – there 5 are types of white blood cells the two main are B and T cells
Antibiotics do not work on viral diseases
Treat symptoms

16. A. I. D. S
ACQUIRED IMMUNE DEFICIENCY SYNDROME

17. How does this work?

18. Virus Images
cold
e bola
herpes
small pox

19. Patients with viral diseases
small pox
mumps
small pox
Patients with viral diseases
SHINGLES
chicken
pox
measles
E BOLA
A I D S
WARTS

20. Cancer Some viruses have been linked to the formation of tumors
HPV is linked to cervical cancer
Hepatitis B and C are linked to liver cancer
Epstein-Barr (mono) linked to lymphoma