1. Viruses, bacteria, viroids, and prions can all cause infection.
Any disease-causing agent is called a pathogen.
1 nanometer (nm) = one billionth of a meter
100 nm
eukaryotics cells 10, ,000 nm
viroids nm
viruses nm
prokaryotics cells ,000 nm
prion 2-10 nm

2. Viruses differ in shape, genetic material, and in ways of entering host cells.
non-living pathogen
can infect many organisms
Viruses have a simple structure.
genetic material (either DNA or RNA)
capsid, a protein shell
maybe a lipid envelope, a protective outer coat

3. Viral Shapes: depends on proteins of capsid
enveloped (influenza)
helical (rabies)
polyhedral (foot-and-mouth
disease)
capsid
nucleic acid
lipid envelope
surface proteins
capsid
surface proteins
nucleic acid
capsid
nucleic acid
lipid envelope
Surface proteins

4. A bacteriophage is a virus that infects a bacterium.
capsid
DNA
tail sheath
tail fiber
HEAD
collar
TAIL
Base plate

5. Viruses enter cells in various ways.
bacteriophages pierce host cells
viruses of eukaryotes enter by
endocytosis or fuse with the membrane

6. LYTIC CYCLE 6

7. 7

8. New vocab words from the cut-out activity:
Host- the cell the virus is infecting
Lysogenic bacteria- a bacterium that has a piece of the viral DNA embedded in it’s own DNA (has a prophage)
Prophage (provirus)- segment of viral DNA that is integrated in the host’s DNA
Cell Multiplication- host cell is dividing and dividing, all the while making copies of the viral nucleic acid

9. Differences between Lytic and Lysogenic Cycles:
Lytic Cycle Lysogenic Cycle

10. Viruses cause many infectious diseases
There are many examples of viral infections.
common cold

11. Viruses cause many infectious diseases
There are many examples of viral infections.
common cold
influenza

12. Viruses cause many infectious diseases
There are many examples of viral infections.
common cold
influenza
SARS

13. Viruses cause many infectious diseases
There are many examples of viral infections.
HIV
HIV-infected white
blood cell
The body has natural defenses against viruses.

14. Vaccines are made from weakened pathogens.
A vaccine stimulates the body’s own immune response.
Vaccines prepare the immune system for a future attack.
Vaccines are the only way to control the spread of viral disease.

15. Immunity- - achieved through the presence of antibodies Antibodies-
proteins produced by the
body to neutralize or destroy toxins
OR disease-carrying organisms
- disease-specific
Antigen-
any foreign substance in the body that triggers production of antibodies
Allergen, bacteria, virus etc.

16. Types of Immunity Active immunity Passive immunity
Long-lasting, sometimes life-long
Usually takes several weeks to develop
Exposure to disease organism triggers production of antibodies
Natural immunity: infection with the disease
Vaccine-induced immunity: exposure to weakened or killed form of disease organism
Passive immunity
Only lasts a few weeks or months
Protection is immediate
Person is given antibodies to a disease rather than producing them on their own
Newborn baby: from mother through placenta or breast-feeding
Blood products: receiving blood with antibodies

17. Lytic v. Lysogenic To complete today with your seatmate
Correctly color the lytic cycle pictures
Correctly order the lytic cycle pictures
Correctly label the lytic cycle pictures