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Transcript of d. Students know there are important differences between bacteria and viruses with respect to their...
BACTERIA AND VIRUS
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.
- 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.
WHAT IS A VIRUS?
Cause disease by disrupting homeostasis Don’t exhibit all life criteria:
Don’t carry out respirationNo growth or development(all they can do is replicate)
Host Cell – where a virus replicates Cannot be killed by antibiotics (medicines)
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.
- Viruses
HOW VIRUSES MULTIPLY Active viruses enter cells and immediately begin to
multiply, leading to the quick death of the invaded cells.
- Viruses
VIRAL REPLICATION – LYTIC CYCLE
1. Attachment – to host cell2. Entry – injects nucleic acid3. Replication – uses energy to
replicate viral nucleic acid4. Assembly – New viruses made (in
30 minutes, 200 new viruses)5. Lysis and Release – Host cell
breaks open, and virus particles are released
THE BACTERIAL CELL Bacteria are
prokaryotes. The genetic material in the cells is not contained in a nucleus.
- Bacteria
WHAT IS BACTERIA? Small cell with all the structures
necessary to carry out its life functions.
2 types of Bacteria:1. Archaebacteria – inhabit extreme
environments2. Eubacteria – live almost
everywhere else.
BACTERIAL REPRODUCTION AsexualBinary Fission – 1. Chromosome replicates, attaches
to plasma membrane2. Cell grows and splits Sexual ReproductionConjugation –Transfers all or part of chromosomes
to another bacteria through its pilus
HOW DO BACTERIA MAKE YOU SICK?
Produce disease in one of 2 ways:1. Damage cells and tissues of
the infected organism directly, by breaking down the cells for food.
2. Release toxins (poisons) that travel throughout the body interfering with homeostasis of the host.
- Viruses, Bacteria, and Your Health
COMMON BACTERIAL DISEASES Many bacterial diseases can be cured
with antibiotics.
COMMON VIRAL DISEASES Unlike with bacterial diseases, there are
currently no medications that can cure viral infections.
- Viruses, Bacteria, and Your Health
GRAPHIC ORGANIZER
Nonliving Can beuseful
Treated withantibiotics
WHITE BOARD QUESTIONS Use your notes and boards to answer
the following questions
WHAT IS AN INFECTIOUS DISEASE? Disease =
a change that disrupts the homeostasis in the body
Pathogens = disease causing agents (what makes you sick)
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
WHAT IS THE ROLE OF PHAGOCYTES? Phagocytes – White blood cells
that surround and destroy pathogens.
Macrophages – Located in body’s tissuesGiant Scavengers – engulf pathogens and damaged cells
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
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
WHAT ARE ANTIBODIES? Antibodies –
proteins produced to react with and disable antigens
Antigens – Foreign substances that stimulate an immune response in the body
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
HOW CAN VACCINATIONS HELP?
Vaccine – substance with weakened, dead, or incomplete portions of pathogen
Produces an immune response
Creates antibodies in the body