Transcript Slide 1

The first person to see many
microorganisms, including bacteria,
which he called animalcules, was
Anton van Leeuwenhoek (1632–
1723).
Leeuwenhoek wasn’t a scientist
by training, but he did learn to
grind lenses very skillfully, and his
small but powerful microscopes
allowed him to see what no one else
has ever had.
Bacteria - Introduction
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The oldest living organisms on earth
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How old are bacteria fossils?
Answer: About 3.5 Billion years old
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How many can fill squared inch of skin?
Answer:
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100,000
Bacteria are single-celled organisms or………..?
Answer: Unicellular
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Can live in extremely harsh environments
* Hot or cold temperatures
* Very acidic
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Many can make their own food. What are they
called?
Answer: Autotrophs
Two
Kingdoms of
Bacteria
Archaebacteria
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“Ancient bacteria”
Oldest organisms on the
planet
Some are close to 4 BYO
Many live in extreme
environments
* Hot springs
* Intestines of animals
* Extremely salty
waters
Eubacteria
Do not live in extreme
environments
 Most are harmless even
helpful
 Many are autotrophs
which is………….?
Answer:
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* Make their own food
* Photosynthesize
* Help make Oxygen
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What are the 3 basic shapes
of bacteria?
1. Bacilli : Rods or sticks
2. Cocci: Spherical or round
3. Spirilla: Squiggly called
spirochetes
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Sizes of bacteria:
From 1.5 um to 750 um or?
Answer:
Micrometer
Bacteria
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Some bacteria are Autotrophs:
a. How do they make their own food?
By Photosynthesis
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Other bacteria are Heterotrophs…………..?
a. Can’t make their own food
b. Saprophytes – use dead organism for food
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How do Bacteria reproduce?
Asexual reproduction called Fission:
One bacterium splits into two identical
bacteria
8 Major Structures of Bacteria
• Capsule
• Cell wall
• Cell membrane
• Ribosomes
• Nucleoid
Cell Membrane
• Flagella
• Pili or Cilia
• Cytoplasm
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8 Major Structures of Bacteria
1) Capsule
Keeps the cell
from drying out
and helps it stick
to food or other
cells
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8 Major Structures of Bacteria
2) Cell wall
Outermost covering
that maintains the
overall shape of the
bacterial cell
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8 Major Structures of Bacteria
3) Cell Membrane
Inner layer allows
only certain things
to enter and leave
the bacteria
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8 Major Structures of Bacteria
4) Ribosomes
Make proteins
and give the
cytoplasm a
granular
appearance
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8 Major Structures of Bacteria
5) DNA
Genetic material of
the bacterium
Why is this
structure NOT
called the nucleus?
Answer:
No Nuclear
membrane
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8 Major Structures of Bacteria
6) Flagella
A whip like tail
some bacteria
have used for
movement
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8 Major Structures of Bacteria
7) Pili or Cilia
Allows
bacteria to
stick to
things or
move
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8 Major Structures of Bacteria
8) Cytoplasm
Clear, jelly-like
material that
makes up most of
the bacterium
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Structures of Bacteria
Why are bacteria 1. Simplest form of
organisms
Prokaryotes?
2. The only organelles
present are the ribosomes
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What is the function of
Ribosomes?
Answer: “ Factories
where proteins are made”
3. No actual nucleus present
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Can live in harsh
environments
Joseph Lister
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In the 1860s, a British surgeon named
Joseph Lister hypothesized that
microorganisms caused infections.
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To test his hypothesis, Lister washed
his hands and surgical instruments
with carbolic acid, a chemical that
kills microorganisms, before
performing an operation.
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After the surgery, he covered the
patients' wounds with bandages
dipped in carbolic acid. Only 15 %
of his patients died from infection,
compared to 45 % who died before.
Louis
Pasteur
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In the 1860s, a French scientist
named Louis Pasteur showed
that microorganisms caused
certain kinds of diseases.
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He also showed that killing the
microorganisms could prevent
the spread of those diseases.
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How is his discovery used
today?
Answer: We pasteurize milk
and juices
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What is pasteurization?
Answer: Heating at high
temperature to kill pathogens
or harmful microorganisms
Robert Koch (1843 – 1910)
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German bacteriologist
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Won the 1905 Nobel Prize in
physiology or medicine
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Koch proved that infectious
diseases were caused by
microorganisms
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Developed techniques for
isolating and identifying
disease-causing bacteria.
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Known as the Father of
Modern Bacteriology
Pathogenic Bacteria
a. What do these bacteria cause?
Answer: Diseases
b. Only small percentage of all bacteria
c. How are they treated?
Answer: With Antibiotics
d. Some produce poisonous substance called Toxin
* Botulism in canned foods
* Tetanus found in dirt
* The toxins produced are one of the deadliest know to man
e. What are Endospores?
* Thick wall produced by bacteria when conditions are
unfavorable
* How long can endospores last?
For hundreds of years
Streptococcus aureus
This type of bacteria is commonly found in the human body.
It causes illnesses such as strep throat, scarlet fever, and
pneumonia.
What is it?
Bacillus anthracis
Anthrax is a serious disease caused by a bacterium. A
cluster of anthrax bacteria, in red, is shown inside a blood
vessel of a human lung.
What is the name of the bacteria that causes anthrax?
Staphylococcus aureus bacteria colony
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Is it harmful or pathogenic?
* YES!!
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What illnesses does it cause?
* Food poisoning
* Toxic shock syndrome
* Skin and wound infections
causing pimples
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How is it treated?
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* With antibiotics, BUT……..
This MRSA or Methicillin Resistant
Staphylococcus aureus causes serious
infections in hospitals
How the Body Fights Bacteria
Some bacteria can cause infections. The body produces
cells that defend against infection by attacking bacteria.
One of these types of cells, is shown in yellow.
Can you name this cell?
Macrophage
Macrophage
This macrophage is a large, mature phagocyte or white
blood cell that can ingest and destroy pathogens, foreign
particles, and cancerous or diseased cells.
Macrophage means “Large eater”.
This macrophage is digesting a bacteria called E. coli.
Do you know where in our bodies E. coli lives?
Large intestine
 Why are they called non-pathogenic?
Non* Because they do not cause diseases!
Pathogenic
Bacteria 1 . Help in the production of food:
* Yogurt
* Cheese
* Sour cream
2. What do some bacteria in the large
intestine produce?
* Vitamin K which is needed for proper
blood clotting
3. Some bacteria help break down dead
organisms and other matter.
What are they called? * Decomposers
Population Explosion
Reading Graphs:
What variable is being
plotted on the horizontal
axis? What is being plotted
on the vertical axis?
Horizontal axis–time
(minutes)
Vertical axis–number of
bacterial cells.
Population Explosion
Interpreting Data:
According to the graph,
how many cells are there
after 20 minutes? 1 hour?
2 hours?
8 cells after one hour;
2 cells after 20
minutes;
64 cells after two
hours.
Review Questions
1. Question: Which scientist is called “The Father of
Modern Bacteriology”?
Answer: Robert Koch
2. Question: What is a “Pathogenic bacteria”?
Answer: A bacteria that causes diseases!!
3. Question: What does MRSA stand for?
Answer: Methicillin Resistant Staphylococcus Aureus
4. Question: What is the French scientist Louis Pasteur
know for?
Answer: He showed microorganism caused diseases
and killing them would prevent the spread of
those diseases
5. Question: What is a “macrophage”?
Answer: A type of white blood cell that can digest bacteria,
other invaders and cancer cells
6. Question: What are the 3 common shapes of bacteria?
Answer: * Bacilli : Rods or sticks
* Cocci: Spherical or round
* Spirilla: Squiggly called spirochetes
7. Question: Why are bacteria prokaryotes?
Answer: * No nuclear membrane
* DNA floats around in cytoplasm
* The only organelles are Ribosomes
8. Question : What are the size ranges for bacteria?
Answer: 1.5 to 750 um or micrometers
9. Question: What is the difference between autotrophs
and heterotrophs?
Answer: Autotrophs make their own food
Ex: Bacteria Plants
Heterotrophs can’t make their own food
Ex: Humans Animals
10. Question: How do autotrophic bacteria make their food?
Answer: By photosynthesis
11. Question: True or False
Most bacteria are pathogenic or disease causing?
Answer: False
Most bacteria are harmless, even helpful