Transcript disease - TeacherWeb

PATHOGENS
EVIL SPIRITS
HOW DO
PATHOGENS
CAUSE
DISEASE?
IMBALANCE
OF
BODY FLUIDS
SWAMP AIR
SCIENTISTS
WHO STUDIED
PATHOGENS
1860
LOUIS PASTEUR
MICROORGANISMS
AND
GERM THEORY
OF
DISEASE
1880’s
JOSEPH LISTER
SURGERY
AND
CARBOLIC ACID
1870’s
ROBERT KOCH
SPECIFIC
MICROORGANISMS
CAUSE
SPECIFIC
DISEASE
TYPES OF
PATHOGENS
VIRUSES
BACTERIA
FUNGI
PROTISTS
WHAT ARE VIRUSES?
• 1. Strand of hereditary material
surrounded by a protein coating
• 2. don’t have a nucleus, cell membrane or
other organelles
• 3. have a variety of shapes
• 4. too small to see with light microscope,
discovered after invention of electron
microscope
previrus.asf
DISEASES CAUSED
BY VIRUSES
•
•
•
•
•
•
COLD SORES
MEASLES
CHICKEN POX
COLDS
FLU
AIDS
CHARACTERISTICS OF
A VIRUS
• 1. Viruses are considered to be non-living
( they do not exhibit all criteria necessary
for life)
• 2. do not have cells
• 3. do not carry out respiration
• 4. do not grow or develop
• 5. cannot live independently
STRUCTURE OF
A VIRUS
• 1. inner core of nucleic acid, either RNA or
DNA
• 2. outer protein coat called a capsid
• 3. arrangement of proteins in capsid
determines the viruses’ 3-D shape that
matches up with the shape of a molecule in
the plasma membrane of the host cell
(like interlocking puzzle pieces- this is how virus
recognizes its host cell)
4. Some larger viruses have an envelope that
surrounds the capsid
usvirus.asf
• http://learn.genetics.utah.edu/content/begi
n/cells/scale/
ATTACHMENT AND INFECTION
• 1. viruses affect all 6 kingdoms
• 2. each virus has a specifically shaped attachment
protein.
• 3. the virus and the place where it attaches must fit
together exactly
• 4. some affect only one type of organism or part of an
organism (example: potato leafroll
• 5. Can be carried to a plant’s surface by the wind or
inhaled by an animal
• 6. rabies affects only mammals
• 7. viruses that affect bacteria are
called bacteriophage
• 8. Bacteriophages attach to a bacterium
and inject their hereditary material
REPLICATION- how do viruses
multiply?
• 1. Since it is not a living organism it must
be inside a host cell to reproduce
• 2. Once inside, it either becomes:
• a. active
• b. latent
ACTIVE VIRUSES
• A. Causes the host cell to make new viruses
and destroys the host cell
• B. Reproduction steps:
• Attach (attaches to surface of the host cell)
• Invade (hereditary material attacks cell)
• Copy (hereditary material controls cell and
makes copies)
• Release ( Cell bursts when “ _full_____ “ and
virus infects other cells
• C. Examples: Common cold, flu/influenza
NPRflu.htm
Release
Attach
Copy
Invade
The Lytic Cycle
LATENT VIRUSES
• A. Virus enters the cell and becomes part
of the cell’s hereditary material without
destroying the cell or reproducing
• B. Can stay latent for years and then
become active. It runs its course but never
leaves the cell.
• C. Examples: hepatitis, herpes, HIV
FIGHTING VIRUSES
• 1. Vaccines are made from weakened or
dead strains of the virus which allow the
host to fight off some diseases
• 2. Famous First Vaccines
– Edward Jenner 1796 developed first vaccine
for smallpox
– Jonas Salk 1955 developed polio vaccine
TREATING AND PREVENTING
VIRAL DISEASE
• A. Antibiotics are only useful with bacteria
• B. Interferons are made by our bodies
(natural defense against viruses)
• C. Antiviral drugs help fight or shorten the
length of a virus
PUBLIC HEALTH MEASURES
•
•
•
•
a.
b.
c.
d.
vaccinating people
improving sanitary conditions
quarantining patients
Controlling animals that spread disease
GENE THERAPY
• 1. Placing of normal hereditary material
enclosed in a virus inside of an infected
cell.
• 2. The virus infects the “targeted cell” and
takes over- “infecting” the body with
normal hereditary material