Download Bacteria in the Environment

Kingdom Monera
(Bacteria and
Archaebacteria)
Prokaryotes
The smallest and most common
of cells are prokaryotes.
They:
 Exist almost everywhere on
earth
 Are cells that do not have a
nucleus
 Do not have membranebound organelles
All prokaryotes are placed into one of two kingdoms:
Eubacteria or Archaebacteria
Eubacteria
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Make up the larger of the
two prokaryote kingdoms
Generally are surrounded
by a cell wall composed
of complex
carbohydrates
Within the cell wall is the
cell membrane that
surrounds the cytoplasm
Bacteria Cell
Cyanobacteria
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Also known as the blue-green
bacteria
Are photosynthetic (Contain
membranes that carry out the
process of photosynthesis)
Contain phycocyanin and
chlorophyll a

Can be found nearly
everywhere on earth.
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Can survive in extremely hot
environments and even
extremely cold environment
Prochlorobacteria
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Prochlorobacteria are a newly discovered group
of organisms.
They contain chlorophyll a & b.
They are more similar to chloroplasts of green
plants.
Only 2 species of prochlorobacteria have been
discovered.
Archaebacteria
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Lack important carbohydrate
found in cell walls
Have different lipids in their
cell membrane, types of
ribosomes, and gene
sequences
Archaebacteria can live in
extremely harsh
environments
They do not require oxygen
and can live in extremely salty
environments as well as
extremely hot environments.
Identifying Prokaryotes
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Cell Shape
Cell Wall
Movement
1) Bacterium Shapes
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Cocci~ Sphere shaped bacteria
Bacillus~ Rod shaped bacteria
Spirrillium ~ Spiral shaped bacteria
Bacteria can
be
arranged
in:
-cluster
-chains
-colonies or
pairs
2) Cell Walls
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To study bacterial cell walls, one must stain it. This is called gram
staining.
Chemical nature of a cell wall can be determined by gram staining
Gram’s stain consists of 2 dyes: crystal violet (purple) and
safranine (red).
By finding out what color the cell produces when it is gram
stained you can figure out the type of carbohydrates in the cell
wall
Gram staining
The bacteria will take up either one or the other stain.
 Gram-positive  bacteria with only one thick layer of
carbohydrates and proteins will take up the crystal violet
Staphylococcus

E. coli
Gram-negative  bacteria with a second, outer layer of
lipid and carbohydrate molecules will take up the safranine
3) Bacterial Movement
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Some have 1 or more flagella
Some lash, snake, or spiral forward
Some secrete slimy stuff
Some don’t move!
http://www.microbiologybytes.com/video/motilit
y.html
Movement
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Flagella ~ Tail like structure
the whips around to propel
the bacterium
Cillia ~ Miniature flagella
surround the cell that help to
“swim”
Non motile ~ Sticky cillia
like structures that keep the
bacterium from moving
Cillia
4) Bacteria and their energy
Autotrophs
 Make their own food
from inorganic
molecules
Heterotrophs
 Consume organic
molecules made by other
organisms
Autotrophs

Phototrophic
autotrophs trap the
energy of the sunlight
Eg. Cyanobacteria

Chemotrophic
autotrophs obtain their
energy from inorganic
molecules
Heterotrophs

Chemotrophic
heterotrophs obtain
their energy by taking in
organic molecules then
breaking them down and
absorbing them

Phototrophic
heterotrophs use the
sun’s energy but they also
need organic compounds
for nutrition
Review:

What type of cells are the most common?
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What are the 4 ways we can identify bacteria?
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Rod (bacilli), sphere (cocci), spiral (spirilla)
What is gram-staining?
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Cell shape, cell wall, movement, obtain energy
What are the 3 basic shapes of bacteria?
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prokaryotes
Gram positive (purple), gram negative (red)
What are the 2 different ways bacteria obtain energy?
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Autotrophic, heterotrophic
Bacterial Respiration

Bacteria need constant energy through
respiration and fermentation

Respiration is the process that involves oxygen
and breaks down food for the release of energy.
Fermentation enables cells to carry out energy
production without oxygen

Bacterial Respiration
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Obligate Aerobes
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Cannot live without
oxygen.
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Obligate Anaerobes
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Must live without oxygen
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Facultative Anaerobes
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Can live with or without
oxygen
Example of an obligate anaerobe:
Clostridium botulinum
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An example of an obligate anaerobe is Clostridium
botulinum, which produces toxins. If these bacteria find
their way into a place that is free of air (O2), and filled
with food material, they will grow very quickly. As they
grow, they produce toxins, or poisons, that cause
botulism. Botulism produces paralysis and if the
breathing muscles are paralyzed, death.
Botox
Bacteria Reproduction
In favorable conditions, bacteria can grow and
divide quickly.
They can reproduce in the following ways:
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Binary Fission
Conjugation
Spore Formation
Cellular organism copies its genetic information then splits into
two identical daughter cells
Conjugation
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A type of Bacteria Sex
Two organism swap
genetic information, that
contains the information
such as a resistance to
penicillin
Spore Formation: Endospore
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A type of dormant
cell
Highly resistant to
environmental
stresses
Endospores are
formed by cells in
response to
environmental signals
that indicate a
limiting factor for
growth, such as
exhaustion of an
essential nutrient.
Importance of Bacteria

Bacteria is often used in:
Food
 Sourdough bread, cheese, yoghurt
 Industry
 Break down oil
 Medical/cosmetic procedures
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Symbiosis
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Bacteria develop a close relationship with other organisms in which
the bacteria and the other organism both benefit
For example: the bacteria E. coli
This is found in the human digestive tract.
The intestine provides a warm safe home with
lots of food.
The bacteria then helps us to digest food and
make some vitamins that we can’t produce
by ourselves.
For cattle, the bacteria in their intestines help them produce the
enzymes necessary to break down cellulose, which is mostly in grass
and hay. Bacteria helps cattle digest their food.
Other types of relationships
Parasitism
 Bacteria exploit the host
cell, injuring them
 Eg. Mychobacterium
tuberculosis
Mutualism
 Relationship in which
two species live together
in such a way that neither
are harmed
Bacteria in the Environment
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Nutrient Flow
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Sewage Decomposition
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Bacteria recycle and decompose, or break down, dead
material
Ie. Bacteria capable of digesting the hydrocarbons in
petroleum are often used to clean up oil spills
Nitrogen Fixation
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Process by which nitrogen in the atmosphere is
converted into a form that can be used by living things
Review

Differentiate between:
Respiration and fermentation
 Obligate aerobes, obligate anaerobes, and facultative
anaerobes
 Binary fission, conjugation, and spore formation
 Symbiosis, parasitism, and mutualism
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Name ways in which we use bacteria today