Transcript Chapter 19- Bacteria

Chapter 19- Bacteria
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I. Bacteria
A. Classifying Prokaryotes
1. Prokaryotes are organisms WITHOUT a
nucleus.
2. Prokaryotes can be divided into
Eubacteria and Archaebacteria.
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B. Eubacteria
1. The larger of the two kingdoms of
prokaryotes is the Eubacteria.
2. They live almost everywhere.
3. Usually surrounded by a cell wall the wall
protects from injury and determines its shape.
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4. The cell wall of Eubacteria contains
peptidoglycan a carbohydrate.
5. Some even have a second membrane
outside the cell membrane. This makes
them VERY resistant to damage.
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C. Archaebacteria
1. They lack a peptidoglycan and they have
different membrane lipids.
2. The DNA sequences of Archae are more like
Eukaryotes then prokaryotes.
3. Most live in extreme environment.
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D. Identifying Prokaryotes
1. Prokaryotes are identical by characteristics
such as shape, the chemical nature of their
cell walls, the way they move and the way
they obtain energy.
2. There are three different shapes of
bacteria.
Rod shaped BacilliCocci
Spirilla
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3. Two different types of cell walls are found in
Eubacteria.
4. Gram staining is used to tell them apart.
5. Gram-positive bacteria are purple, they have
thicker walls.
6. Gram-negative bacteria are red or a light
pink, they have thinner walls.
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7. Some prokaryotes do not move at all.
8. Some glide, lash or have slime they
secrete when they move.
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COVER YOUR MOUTH!!!
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COVER YOUR MOUTH!!!
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E. Metabolic Diversity
1. Heterotrophs- must take in food.
2. Chemoheterotrophs take in organic
molecules for energy and a supply of
carbon.
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3. We are Chemoheterotrophs.
4. Photoheterotrophs photosynthesize but
also must obtain organic compounds.
5. Autotrophs make their own food.
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6. Photoautotrophs use sunlight to make
food.
7. Chemoautotrophs make food from
carbon dioxide but not using the sun they
make it by chemical reactions.
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F. Releasing energy
1. Bacteria need a constant supply of energy.
2. Bacteria that need oxygen are called obligate
aerobes.
3. Bacteria that DO NOT NEED oxygen, actually
DIE if there is oxygen present are called obligate
anaerobes.
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4. Bacteria that can live with or without
oxygen are called facultative anaerobes.
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G. Growth and reproduction- bacteria
reproduce three different ways.
1. Binary fission- Bacteria grows and
grows and splits in half. Exact copes.
2. Conjugation- bacteria exchange
genetic information.
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3. Spore formation- when growth conditions
become unfavorable many bacteria produce
spores.
a. One type of a spore is called an endospore.
b. Spores can remain dormant for months.
c. When conditions improve, the endospore will
germinate and the bacterium will grow again.
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H. Importance of bacteria
1. Bacteria are vital to maintaining the living
world.
2. Some are producers that capture energy by
photosynthesis.
3. Others are decomposers breaking down
nutrients in dead matter.
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4. Bacteria breakdown dead and
decaying organisms.
5. Help to recycle nutrients – which helps
to maintain equilibrium in the
environment.
6. Bacteria also help perform critical steps
in sewage treatment.
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Flesh eating bacteria
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7. Others have human uses.
8. Bacteria convert nitrogen gas into a form
plants can use, this is called nitrogen fixation.
9. Nitrogen fixation allows nitrogen atoms to
continually cycle through the biosphere.
10. Bacteria are also used to make some foods
such as: pickles, ice cream, yogurt, and other
things.
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II. Viruses
A. What is a virus?
1. A typical virus is composed of a core
DNA or RNA surrounded by a protein coat.
2. A virus’s protein coat is called its
capsid.
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3. The capsid includes proteins that
enable a virus to enter a host cell.
4. Viruses that infect bacteria are called
bacteriophages.
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B. Viral infections
1. Once a virus is inside the host cell, two
different processes may occur.
2. Lytic cycle- virus enters a cell, makes
copies of it and causes the cell to burst.
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3. Lysogenic infection- a virus integrates
its DNA into the DNA of the host cell, and
the viral genetic information replicates
along with the hosts cell’s DNA.
4. The viral DNA that is embedded in the
host’s DNA is called a prophage.
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C. Retroviruses
1. Some viruses contain RNA as their
genetic information and are called
retroviruses.
2. When retroviruses infect a cell, they
produce a DNA copy of their RNA.
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3. The DNA is inserted into the host cell
they will infect.
4. Retroviruses get their name because
their genetic information is copied
backwards.
5. Usually DNA-RNA, but retrovirus goes
RNA-DNA
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D. Viruses and living cells
1. Viruses must infect a living cell in order
to grow and reproduce.
2. Are viruses alive?
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III. Diseases
A. Bacterial Disease in Humans
1. Disease causing agents are called
pathogens.
2. Bacteria produce disease in one of two
ways.
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3. Some bacteria damage the cells and tissues
of the infected organisms directly by breaking
down the cells for food.
4. Other bacteria release toxins that travel
throughout the body interfering with the normal
activity of the host.
5. Tuberculosis- TB is inhaled into the lungs and
destroys lung tissue.
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6. Bacteria also release toxins in the body, like
strep throat.
7. These toxins if go untreated could cause
scarlet fever.
8. Diphtheria also infects the throat. It releases
toxins and if it goes untreated could cause
breathing problems, heart failure, paralysis and
death.
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9. A vaccine is a preparation of weakened
or killed pathogens.
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body will produce immunity to the
disease.
11. Immunity is the body’s ability to
destroy new pathogens.
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12. Antibiotics are drugs that can attack and
destroy the invading bacteria.
13. Bacterial diseases also affect animals.
14. There are various methods used to control
bacteria growth- sterilization disinfectants and
food processing.
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15. Viruses produce disease by disrupting the
body’s normal equilibrium.
16. Viruses attack and destroy certain cells in
the body, causing the symptoms of the disease.
17. Many viruses infect plants also.
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18. Many plants, like potatoes, tomatoes,
apples and citrus fruits can be infected by
viroids.
19. Viroids are single stranded RNA
molecules that have no surrounding
capsid.
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20. Prions are short for protein infectious
particles.
21. Mad cow disease is thought to be
caused by Prions.
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22. Bird flu is a virus.
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The End
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