1. Virus Replication

2. What is a Virus?
Virus: A biological particle composed of nucleic acid and protein
Intracellular Parasites: organism that must “live” inside a host

3. Are viruses alive? No Yes Not made of cells or organelles
Can’t reproduce on own
Don’t metabolize energy
Don’t perform cellular processes
Reproduce
Have nucleic acid
Adapt to surroundings
Have organization

4. All Have:
1) Capsid: coat of protein that surrounds nucleic acid
2) Nucleic Acid: RNA or DNA
Some Have:
Tail Fibers: Used for attachment (not legs)
Shapes vary
Virus
Parts

5. Virus Video

6. Viral Replication Bacteriophages (infect bacteria) are often studied
Replication is similar with many animal viruses

7. The Lytic Cycle 1st Step: Attachment Virus lands on cell membrane
Virus attaches to a cell receptor
No attachment = No infection
Virus acts as key; receptor acts as lock

8. The Lytic Cycle 2nd Step: Entry Virus enzyme weakens cell membrane
endocytosis
2nd Step: Entry
Virus enzyme weakens cell membrane
Genetic material (DNA or RNA) enters host cell

9. The Lytic Cycle 3rd Step: Replication
Virus DNA/RNA uses ribosomes to make virus proteins
Virus proteins created by transcription/ translation
Viral DNA  Viral RNA  Viral Amino Acids  Viral Proteins

10. The Lytic Cycle 4th Step: Assembly
New virus proteins are assembled in the cytoplasm

11. The Lytic Cycle 5th Step: Release
Virus enzyme causes cell membrane lyse (burst)
Viruses are released to find new host
Cycle repeats

12. The Lysogenic Cycle
1st step: Attachment = Same
2nd Step: Entry = Same

13. Lysogenic Cycle 3rd step: Replication
Virus DNA combines with cell DNA, and waits
Provirus = cell DNA + viral DNA
Cell divides by mitosis
Each new cell will contain the provirus

14. Host cell DNA
Pro-virus

15. Pro-virus
Pro-virus
Pro-virus

16. Pro-virus
Pro-virus

18. The Lysogenic Cycle
4th Step: Assembly Same, except many new viruses are being assembled in many cells
5th Step: Release
Same, except many cells burst releasing many more viruses

19. The viral DNA become active and starts making new viral proteins
The infected cells burst…releasing the new viruses

20. Retroviruses RNA viruses Contains the enzyme Reverse Transcriptase
Steps
1) Virus RNA enters host cell.
2) Reverse transcription takes place to make virus DNA
3) Virus DNA combines with cell DNA (provirus created)
4) Once active, normal steps of transcription/translation followed.

21. How is HIV contracted? High risk activities: Low risk activities:
1) Sex (oral, vaginal, anal)
2) Sharing needles (tattoos, piercings, drugs)
Low risk activities:
3) Mother to child in womb
4) Breast milk
5) Blood transfusions

22. Adults and children estimated to be living with HIV/AIDS as of end 2001
Eastern Europe & Central Asia
1 million
Australia
& New Zealand
15 000
East Asia & Pacific
Western Europe
North Africa
& MiddleEast
North America
Caribbean
Sub-Saharan Africa
28.1 million
South
& South-East Asia million
Latin America
1.4 million
Total: 40 million

23. What is AIDS? Acquired Immunodeficiency Syndrome AIDS results when:
New Exposures to HIV (2006)
Gender of those living
with HIV (2003)
Acquired Immunodeficiency Syndrome
AIDS results when:
1) Amount of T-cells drop (200 T-cells per 1mm³ blood)
2) Multiple symptoms/infections appear
Rash, fever, headache, sore throat, swollen lymph nodes
Therefore, the HIV virus causes the disease AIDS by killing your T-cells

24. Want more stats? Go to the Centers for Disease Control’s Website
Female Transmission of HIV
(2006)
Male Transmission of HIV
(2006)
Want more stats? Go to the Centers for Disease Control’s Website

25. AIDS Quilt
3ft x 6ft quilt panel
can be created as
a memorial tribute

26. AIDS Quilt
Panels from across
the world are
sewn together

27. Panels travel around the world to help remember and raise awareness
AIDS Quilt
Panels travel around the world to help
remember and raise awareness

28. AIDS Quilt
Over 44,000 panels
exist today