Download Reproduction of Bacteria

There are more bacteria on Earth
than all other living things
combined!
• Sizes vary, but most cannot be see w/o a
microscope
Characteristics of Bacteria
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Two kingdoms
All single-celled (unicellular)
Prokaryotes (no nucleus)
Rigid cell wall
Charac. Contd.
• Three main shapes:
– Bacilli-rod shaped
– Cocci-spherical
– Spirilla-long and spiral shaped
3 Shapes of Bacteria
Bacteria are classified by shape into 3 groups:
Spiral:
Spirilla, spirillum
rod-shaped: bacilli,
bacillus
Round:cocci
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3 Shapes of Bacteria
Bacillus anthracis – (bacillus)
Neisseria meningitidis (coccus)
Leptospira interrogans – (spirilla)
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7 Major Structures of a Bacteria Cell
•Capsule
•Cell wall
•Ribosomes
•Nucleoid
•Flagella
•Pilli
•Cytoplasm
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7 Major Structures of a Bacteria Cell
Capsule
 keeps the cell
from drying out and
helps it stick to food
or other cells
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7 Major Structures of a Bacteria Cell
Cell wall
Thick outer
covering that
maintains the
overall shape of
the bacterial cell
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7 Major Structures of a Bacteria Cell
Ribosomes
 cell
part where
proteins are made
 Ribosomes give the
cytoplasm of bacteria a
granular appearance in
electron micrographs
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7 Major Structures of a Bacteria Cell
Nucleoid
 a ring made up of
DNA-the genetic
material
(chromosome)
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7 Major Structures of a Bacteria Cell
Flagella
 a whip-like tail
that some bacteria
have for locomotion
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7 Major Structures of a Bacteria Cell
Pilli
 hollow hair-like
structures made of
protein
allows bacteria to
attach to other cells.
Pilli-singular
Pillus-plural
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7 Major Structures of a Bacteria Cell
Cytoplasm
 clear jelly-like
material that makes
up most of the cell
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• Some bacteria
contain a
plasmid- An
extra, circular
piece of DNA
• Independent of
the nucleoid and
can replicate
separately and
may be
transferred
between
bacteria
Reproduction of Bacteria
•Binary Fission- the process of one organism
dividing into two organisms
•Fission is a type of asexual reproduction
•Asexual reproduction- reproduction of a living thing from only
one parent
How?...
The one main (circular)
chromosome makes a copy of itself
Then it divides into two
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Bacterial reproduction
• Binary fissionasexual
reproduction where
one cell splits into
two identical cells
Reproduction of Bacteria
BINARY FISSION
Bacteria dividing
Completed
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Reproduction of Bacteria
•The time of reproduction depends on how desirable the
conditions are
•Bacteria can rapidly reproduce themselves in warm, dark, and
moist conditions
•Some can reproduce every 20 minutes
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Conjugation
• Reproduction in
bacteria that
results in the
exchange of
genetic
information
Bacteria Survival
Endospore•a thick celled structure that forms inside
the cell
•they are the major cause of food poisoning
•allows the bacteria to survive for many years
•they can withstand boiling, freezing, and
extremely dry conditions
•it encloses all the nuclear materials
and some cytoplasm
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Bacteria Survival
Bacillus subtilis
Endospore-the black section in the middle
highly resistant structures
can withstand radiation, UV light, and boiling at 120oC for 15 minutes.
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Bacteria Survival – Food sources
parasites – bacteria that feed on living things
saprophytes – use dead materials for food (exclusively)
decomposers – get food from breaking down dead matter into simple chemicals
important- because they send minerals and other materials back into the
soil so other organisms can use them
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Kingdom Eubacteria
• Has more individuals than all of the other 5
kingdoms combined
• Classified by how get food:
– Consumers (eat other organisms)
– Decomposers (break down dead organisms)
– Producers (make food)
Kingdom Archaebacteria
• Prefer harsh environ. with little or no
oxygen
• 3 main types:
– Thermophiles or Thermoacidophiles-Heat
lovers (hot springs, volcanic vents)
– Halophiles- Salt lovers (highly salty water)
– Methanogens- Methane makers (swamps &
animal intestines)
Bacteria are good for the
environment!
• Nitrogen fixation -change nitrogen from air
into form plants can use
• Recycling- Break down dead plants &
animals
• Bioremediation- Fight pollution, change
harmful chemicals into harmless ones
Also good for people!
• In food- Make cheese, yogurt, etc.
• Medicines- antibiotics
• Insulin- bacteria can make human insulin,
given to diabetics
• Genetic engineering- can make
insecticides, cleaners, & adhesives
Helpful Bacteria
E.coli on small intestines
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Some bacteria are harmful!
• Pathogenic bacteria- cause disease
• Not only in humans; but in other animals,
plants, protists, fungi, & other bacteria!
• Ex. In humans: tetanus & diptheria
Harmful Bacteria
•Animals can pass diseases to humans
Communicable Disease –
Disease passed from one organism to another
This can happen in several ways:
•Air
•Touching clothing, food, silverware, or toothbrush
•Drinking water that contains bacteria
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What is a virus?
• Microscopic particle that gets inside a cell
& often destroys
• Strand of genetic material surrounded by a
protein coat
• Many cause diseases:
– Common cold
– Flu
– Chickenpox
– AIDS
Little Bitty
• Viruses are smaller
than the smallest
bacteria
• 5 billion virus particles
can fit into a single
drop of blood
Not living!
• Cannot grow, eat, break down food, or use
oxygen
• Uses a host cell’s machinery
• Host-living thing a parasite or virus lives
on
Lytic Cycle
Lytic & Lysogenic Cycles