CHAPTER 18: BACTERIA & VIRUSES
Bacteria
- Most
successful organisms on earth
- Earliest
group of living organisms on earth (evolved 3.5 BYA)
- Live
everywhere
- They
are the only organisms to be classified as Prokaryotes
Bacteria exist in 3 different shapes:
| Rod |
Spherical (Round) |
Spiral |
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| Exanples: |
Examples: |
Examples: |
Traits of Prokaryotes (Bacteria):
- _____________________________________________________________
- _____________________________________________________________
- _____________________________________________________________
- _____________________________________________________________
- _____________________________________________________________
Bacteria Can Be Classified According to
these 3 things:
Bacteria Can have 2 different types of cell
walls:
1.
_________________________________________________
2.
________________________________________________
__________________________________ - A special
staining procedure that reveals the chemical difference between the 2 types of bacterial
cell walls.
This staining procedure is important in diagnosing
diseases caused by bacteria because:
Bacteria Reproduce by:
1.
____________________________________________
-
2.
_____________________________________________
-
Bacteria reproduce __________________.
Bacterial Nutrition
Bacteria are successful because they can use a
wide variety of foods.
- ___________________________ bacteria can make their own food:
____________________________:
Converting light energy into food molecules
____________________________:
Making complex organic molecules from energy in inorganic molecules, such as ammonia or
methane.
- ___________________________ bacteria feed on dead animals, plants, wastes,
fallen leaves & branches.
Most bacteria are ______________________, they
feed off of living things, causing disease.
HOW BACTERIA AFFECT HUMANS
Beneficial Bacteria:
1.
____________________________________________
- Return nutrients to the environment by breaking down organic matter, releasing CO2,
N, P, S, H2O, nutrients that plants need to grow.
2.
______________________________________________
- Convert atmospheric nitrogen to ammonia (a Nitrogen compound that plants can absorb)
3.
______________________________________________
- Adds flavor to foods (cabbage -> sauerkraut, cucumbers-> pickles); produce dairy
products (yogurt, sour cream); produce insulin & antibiotics
Harmful Bacteria:
1.
______________________________________________
- Disease-causing bacteria. They cause damage to hosts’ tissues, may be transmitted
through the air, and produce toxins that attack cells.
2.
____________________________________________
- Bacteria ferment sugars on teeth -> lactic acid is produced -> loss of calcium
-> break down of proteins in tooth enamel
3.
______________________________________________
- Stress creates an environment beneficial to bacterial growth.
4.
______________________________________________
- Botulism, Salmonella, E. coli, Cholera are examples of bacteria spread in this fashion.
To prevent
contamination:
Bacteria can be spread through the air
(examples): Tuberculosis, diptheria, whooping cough
Prevention & Control of
Bacterial Disease
- _______________________________________________ - Heating food to a
temperature that kills most bacteria
- _______________________________________________ - Cooling foods to
temperatures too cold for most bacteria to grow
- _______________________________________________ - Keep water supplies clean,
using chlorination & regulation of water. ________________ is an example of a disease
spread this way. This disease primarily occurs in developing countries, and consists of
acute diarrhea & vomiting.
- _______________________________________________ - Injection of a solution
(vaccine) that contains inactivated pathogens that ultimately stimulate an
_________________________________ to that pathogen. When exposed to that pathogen in the
future, you will have antibodies to fight off the impeding infection.
(Refer
to figure 18-11 to see how a vaccine works)
- _______________________________________________
- Drugs that fight or kill bacteria. ____________________________, a British
bacteriologist, discovered a mold, Penicillum (Penicillin) that prevented growth of
bacteria in his cultures. Antibiotics prevent bacterial growth by:
Examples of antibiotics: Penicillin, Tetracyclin, Streptomycin
Bacterial Resistance to
Antibiotics
Many bacteria are becoming resistant to
antibiotics because of _______________ and ________________ of antibiotics.
Bacteria acquire resistance through:
Refer to figure 18-13.
VIRUSES
Microscopic
particles that invade the cells of plants, animals, fungi & bacteria. They usually
destroy the cells they invade.
Traits of Viruses
- _____________________________________________________________
- _____________________________________________________________
- _____________________________________________________________
Viruses are not considered to be Alive
because:
- _____________________________________________________________
- _____________________________________________________________
- _____________________________________________________________
If viruses are not living things, then why do we
study them in biology?
Tour of an AIDS Virus (p. 346)
- Caused by ___________ (Human Immunodeficiency Virus)
- AIDS is a ___________________ - Contains ________ as its genetic material.
Once inside human _______________ cells, an enzyme called ___________________ ____________________ makes a DNA version of the
HIV RNA genome.
- Outer lipid envelope is derived from the membrane of a __________ cell.
- ____________ proteins are incorporated into the ______________ _________________. These proteins enable the virus
to ________________ _________________ in the
host cell’s membrane.
- ________________ ________________
surrounds ____________
- Protein capsid protects _______________
____________ ___________.
How viruses Reproduce
(Life cycle of the HIV Virus) (fig 18-15)
- __________________ _________________
of virus binds to specific _________________ proteins n the cell’s surface.
- _______________ enters ______________
- Viral _________ is released into _____________
- Viral enzyme, ___________________ __________________,
makes a DNA copy of the viruses’ _________
- __________ cell produces __________ _____________
& _____________ -> viruses _________________
- Newly formed ______________ break out of ___________ cell by _____________ or
____________ cell membrane, killing the host cell
HIV destroys large numbers of ____________ that
fight _______________ in the body. In early stages, only _____________ symptoms appear.
Within 10 years, T-cell levels can drop drastically. When T-cell levels have gone below
__________, a person is said to have “AIDS,” Acquired Immunodeficiency
Syndrome.” Patients die of ________________ __________________that
their bodies cannot fight due to lack of defense from the _____________ system, more
specifically from _______________.
Diseases Cause by Viruses
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Defense Against Viruses
Antibiotics cannot be used to treat viruses
because:
Effective Treatments include:
- _______________________________________________ - AZT is used for AIDS
patients. It blocks an enzyme essential for replication
- _______________________________________________ - Viruses are inactivated by
treatment with chemicals or genetic engineering -> injected into patient -> immune
system builds ______________ to fight the virus upon future exposure.
- _______________________________________________ - T Cells, B Cells,
Lymphocytes, Neutrophils, and other defenses.
Vaccines do not protect against
ALL viruses
___________, ____________ virus & ___________
virus have surface proteins whose genes constantly _______________ & ______________.
_____________ system does not recognize new surface proteins and cannot fight the mutated
virus.