Transcript Prokaryotes and Viruses

PROKARYOTES AND VIRUSES
Eubacteria – Structure, Metabolism and Reproduction
Archaea – Structure, Metabolism and Reproduction
Viruses – Structure, Metabolism and Reproduction
EUBACTERIA – STRUCTURE
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made of prokaryotic cells that include the following structures:
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capsule
 sticky outer coating that prevents water loss, resists high temperatures and
controls entry to cells
 only found in some bacteria
cell wall
 made of peptidoglycan
cell membrane
DNA
 large chromosome
 plasmid – small loop of DNA
ribosomes
pilli
 cytoskeleton projections on the outside of cell
 allow for conjugation
flagellum
 cytoskeleton projections on the outside of cell
 allow for movement
EUBACTERIA - STRUCTURES
shapes, size and arrangement are variable
 three common shapes include:
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coccus bateria
 round shape
 bacillus bacteria
 rod shape
 spirillum bacteria
 spiral shape
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three common arrangements include:
diplo arrangement
 bacteria that exist in pairs
 staphylo arrangement
 bacteria that exist in clumps
 strepto arrangement
 bacteria that exists in strings
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EUBACTERIA – METABOLISM
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metabolism varies between eubacteria
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can be classified by how they obtain nutrients
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autotrophic bacteria
 create their own food using inorganic substances
heterotophic bacteria
 consume other organisms containing organic substances
can be classified by their need for oxygen
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obligate aerobe bacteria
 require oxygen to break down food for energy
facultative aerobe bacteria
 can use oxygen to break down food for energy (aerobic respiration and
fermentation)
 can break down food without oxygen (anaerobic respiration and
fermentation)
obligate anaerobes
 cannot live in the presence of oxygen
EUBACTERIA – REPRODUCTION
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reproduce asexually
using binary fission
1.
2.
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cell grows
chromosomes duplicate
cell grows
cell divides into two
cells
daughter cells have the
same genetic makeup as
the parent cell
EUBACTERIA – REPRODUCTION
are able to exchange DNA
or acquire new DNA from
their environment to
increase genetic diversity
 conjugation
 two eubacteria attach
using their pilli
 a copy of a plasmid
passes from one
eubacteria to another
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http://www.youtube.com/watch?v=O-EdX4MaMFE&feature=related
EUBACTERIA – REPRODUCTION
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transformation
 eubacteria pick up
discarded DNA from their
surroundings and
incorporate this DNA into
their chromosome
 if DNA comes from a
different species this
process is known as
horizontal gene transfer
http://www.youtube.com/watch?v=MRBdbKFisgI&feature=related
EUBACTERIA – EXAMPLES
Type
Characteristics
proteobacteria
• most are photosynthetic
• thought to be ancestors of
mitochondria
• cause many diseases
• bubonic plague,
gonorrhea, ulcers
green
bacteria
• photosynthetic
• found in salt-water and hot
springs
cyanobacteria
• photosynthetic
• thought to be ancestors of
chloroplasts
• found in aquatic ecosystems
as producers and
decomposers
Picture
EUBACTERIA – EXAMPLES
Type
Characteristics
gram-positive
bacteria
• cause many diseases
• strep throat, meningitis
• used in food production
• yogurt
spirochetes
• spiral shaped flagellum to
move in a corkscrew pattern
• cause syphilis
chlamdias
• parasites
• cause chlamydia
Picture
ARCHAEA – STRUCTURE AND REPRODUCTION
Structure
 made up of prokaryotic cells that include the
following structures:
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cell wall
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with no peptidoglycan
cell membrane
 DNA
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Reproduction
 reproduce asexually
 mechanism is unknown
 most likely similar to binary fission
ARCHAEA – METABOLISM
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metabolism varies between archaea
methanogens
 live in low-oxygen environments (swamps, marshes, digestive
tracts of mammals and insects)
 use methane to generate energy
 halophiles
 live in high salt environments (Dead Sea, foods preserved by
salting)
 use light and other organisms to generate energy
 extreme thermophiles
 live in hot environments (hot springs and hydrothermal vents)
 use heat energy to generate energy
 psychrophiles
 live in cold environments (Antarctic and Arctic oceans)
 mechanism to generate energy is unknown
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VIRUSES – STRUCTURE
not made of cells
 non-living structures that
include the following
components:
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DNA or RNA
viruses that contain DNA are
called DNA viruses
 hepatitis B
 viruses that contain RNA are
called RNA viruses
 HIV/AIDS
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capsid
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protein coat that surrounds the
genetic material of the virus
VIRUSES - STRUCTURE
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more complex viruses can
also include:
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envelop
created on the outside of a
viruses when it leaves the
host cell
 part of the host cell’s
membrane
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sheath, plug and tail fibers
found only in bacteriophages
(phages)
 viruses that infect bacteria
 structure used to inject
genetic material into the host
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VIRUSES – METABOLISM
only active when they have infected a living cell
 do not perform any life functions on their own
 have no metabolic structures or systems
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VIRUSES – REPRODUCTION
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only active when they have
infected a living cell
1.
Virus infects host cell and inserts
DNA/RNA into the host.
2.
Viral DNA/RNA forms a loop.
3.
DNA/RNA can be copied by
inserting itself into the hosts
chromosomes (lysogneic cycle).
4.
DNA/RNA instructs cells to make
new viral DNA/RNA and capsids
(lytic cycle).
5.
Newly formed viruses are released
when the host cell burts (lytic
cycle).
http://www.youtube.com/watch?v=Rpj0emEGShQ