1. Bacteria and Virus

2. Standard
d. Students know there are important differences between bacteria and viruses with
respect to their requirements for growth and replication, the bodys primary defenses against bacterial and viral infections, and effective treatments of these infections.

3. - Viruses
What Is a Virus?
A virus is a tiny nonliving particle that enters and then reproduces inside a living cell. Virus particles are tiny compared to bacteria.

4. What is a Virus? Cause disease by disrupting homeostasis
Don’t exhibit all life criteria:
Don’t carry out respiration
No growth or development
(all they can do is replicate)
Host Cell – where a virus replicates
Cannot be killed by antibiotics (medicines)

5. The Structure of Viruses
All viruses have two basic parts: a protein coat that protects the virus and an inner core made of genetic material. Some viruses are surrounded by an outer membrane envelope.

6. How Viruses Multiply - Viruses
Active viruses enter cells and immediately begin to multiply, leading to the quick death of the invaded cells.

7. Viral Replication – Lytic Cycle
Attachment – to host cell
Entry – injects nucleic acid
Replication – uses energy to replicate viral nucleic acid
Assembly – New viruses made (in 30 minutes, 200 new viruses)
Lysis and Release – Host cell breaks open, and virus particles are released

8. - Bacteria
The Bacterial Cell
Bacteria are prokaryotes. The genetic material in the cells is not contained in a nucleus.

9. What is Bacteria?
Small cell with all the structures necessary to carry out its life functions.
2 types of Bacteria:
Archaebacteria – inhabit extreme environments
Eubacteria – live almost everywhere else.

10. Bacterial Reproduction
Asexual
Binary Fission –
Chromosome replicates, attaches to plasma membrane
Cell grows and splits
Sexual Reproduction
Conjugation –
Transfers all or part of chromosomes to another bacteria through its pilus

11. How do bacteria make you sick?
Produce disease in one of 2 ways:
Damage cells and tissues of the infected organism directly, by breaking down the cells for food.
Release toxins (poisons) that travel throughout the body interfering with homeostasis of the host.

12. Common Bacterial Diseases
- Viruses, Bacteria, and Your Health
Common Bacterial Diseases
Many bacterial diseases can be cured with antibiotics.

13. - Viruses, Bacteria, and Your Health
Common Viral Diseases
Unlike with bacterial diseases, there are currently no medications that can cure viral infections.

14. Graphic Organizer
Nonliving
Can be
useful
Treated with
antibiotics

15. White Board Questions
Use your notes and boards to answer the following questions

16. What is an Infectious Disease?
a change that disrupts the homeostasis in the body
Pathogens =
disease causing agents (what makes you sick)

17. Our Bodies Defense Mechanisms:
Skin –
the first line of defense
Phagocytes, B-lymphocytes, and T- lymphocytes –
the 2nd line of defense
Antibiotics and Vaccines –
outside sources of help

18. What is the role of Phagocytes?
Phagocytes – White blood cells that surround and destroy pathogens.
Macrophages –
Located in body’s tissues
Giant Scavengers
– engulf pathogens and damaged cells

19. What if phagocytes don’t help?
Acquired Immunity –
defense against a specific pathogen by building up resistance
Lymphatic System –
the body’s system that is in charge of keeping it healthy
Uses
T-cells and B-cells

20. What are T and B cells all about?
Produced in bone marrow
Helper T-cell
– activates B-cells
Cytotoxic T-cell –
“killer T-cells”
B-cells –
produce antibodies once activated by helper T-cells
Memory B-cells
– remain in blood stream armed and ready for a 2nd attack

21. What are antibodies? Antibodies – Antigens –
proteins produced to react with and disable antigens
Antigens –
Foreign substances that stimulate an immune response in the body

22. What about Antibiotics?
Substance produced by a microorganism that kills or inhibits the growth of other microorganisms
Use to fight and kill
bacteria
Does NOT work
with viruses

23. How can Vaccinations help?
Vaccine –
substance with weakened, dead, or incomplete portions of pathogen
Produces an
immune response
Creates
antibodies in the body