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Presentation on theme: "Viruses."— Presentation transcript:

1 Viruses

2 Virus “intracellular parasites”
small infectious agent that can replicate only inside the living cells of organisms

3 Chicken Pox and Shingles Virus

4 Virion: an entire virus particle
Consists of: DNA or RNA Protein Coat – called a capsid Sometimes a lipid envelope around the protein coat You Tube Lytic Cycle (2:17)

5 Bacteriophage Virus capsid

6 Sometimes glycoprotein spikes to help the virus enter and exit the host cell

7 LYTIC INFECTION Animation of a Lytic Infection
McGraw Hill Life Cycle of a T2 Phage

8 HIV The Human Immunodeficiency Virus (HIV)
Can lead to AIDS (acquired immunodeficiency syndrome)

9 HIV INFECTION HIV infection: a retrovirus (high level)
Shows receptors and how anti-viral drugs can be effective HIV budding from a lymphocyte

10 Lytic Infection

11 Examples Lytic Infections
Common Cold Influenza Rabies TMV (tobacco mosaic virus)

12 Lysogenic Infection

13 Temperate Viruses Also called lysogenic viruses
are those that reproduce without killing their host cell.

14 Common Lysogenic Virus
Herpes (genital and cold sore) Papilloma HPV (cervical cancer) Retrovirus Hepatitis B Chicken Pox

15 Retroviruses Retroviruses use RNA instead of DNA as their nucleic acid core. also contain the enzyme reverse transcriptase

16 Retrovirus Examples HIV Rous sarcoma (first one discovered)
Leukemia viruses

17 Viroids Viroids are naked circular RNA (no protein coat) molecules that are several hundred nucleotides long. Infect plants

18 Viroid Attack on Potatoes
Used to make varieties in flowers

19 Prions a form of a normal protein that is not folded correctly.
Cause degenerative brain disease

20 Mad Cow Disease BSE = bovine spongiform encephalitis
It's ...BSE You Tube Can cause CJD in humans

21 CJD Creutzfeldt-Jakob disease (CJD) is a form of brain damage that leads to a rapid decrease of mental function and movement. You Tube The BSE Prion and Variant CJD

22 Vaccines “Harmless” variants or derivatives of pathogenic microbes that stimulate the immune system to make antibodies against the pathogen.

23 Edward Jenner First Vaccine (for smallpox)
Gave cowpox to his son first Lots of people were getting smallpox

24 BACTERIA Prokaryotes Most of its DNA is in a single chromosome

25 Bacteria Can Transfer DNA in 3 Ways
1. Transformation – uptake of foreign DNA from the surrounding environment 2. Transduction – transfer of bacterial genes by a bacteriophage 3. Conjugation – physical union of two bacterial cells as they “mate”

26 Transformation

27 Transduction

28 Conjugation

29 Bacterial Plasmids F Factor = fertility plasmid

30 F Plasmid Resistance Plasmid Carry genes to destroy antibiotics

31 Identifying Bacteria McGraw Hill Prokaryotic Cell Shapes


33 Can you name these shapes?

34 Can you name these shapes?
A Bacilli with and without flagella B Streptococci C Staphylococci D Diplococci E Spirochete F Club rod G Filamentous H Streptobacilli

35 Spores dormant, tough, and non-reproductive structure produced by certain bacteria

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