The Cell Structures
• Bacteria are PROKARYOTES = genetic
material is not contained in a nucleus.
• DNA in a bacteria cell is found floating in
• A FLAGELLUM = a long whip-like
structure that helps a cell to move.
FLAGELLA = plural of FLAGELLUM
• A bacteria can have many flagella, one
flagellum, or no flagella.
The three basic shapes of bacteria are:
• The chemical make-up of the cell wall
determines the shape of a bacterial cell.
The shape helps Scientists identify the
type of bacteria.
The size of bacteria vary greatly:
The largest bacteria = as big as a period at
the end of a sentence.
Average bacteria = much smaller
They are usually measured in micrometers
(μm) or millionths of a meter.
OBTAINING FOOD AND ENERGY
All bacteria need the following to survive:
1. A source of food
2. A way of breaking down the food to
Some bacteria are AUTOTROPHS
An AUTOTROPH = organisms that make
their own food.
Q: Are humans autotrophs?
• The 2 ways autotrophic bacteria make
1. Some capture and use the Sun’s energy to
2. Some use the energy from chemicals in their
environment to make their food.
• A HETEROTROPH = organisms that
cannot make their own food.
Q: Are humans heterotrophs?
• Heterotrophic bacteria must consume
other organisms or the food that other
Respiration (remember this?)
• Respiration = the process of breaking
down food with the use of oxygen.
• All bacteria do not need oxygen. Some
use FERMENTATION! Do you
Bacteria reproduce frequently when:
1. They have plenty of food
2. The right temperature
3. Other conditions (water, the right
• Under the best conditions (ideal) bacteria
can reproduce as often as once every 20
• BINARY FISSION = the process of
reproduction in bacteria where 1 cell
divides to form 2 identical cells. It is a
type of ASEXUAL REPRODUCTION =
the reproductive process that involves only
1 parent and produces offspring that are
identical to the parent.
• Binary Fission (a type of Asexual
Reproduction) is just like CELL DIVISION,
what we studied not too long ago.
For Animal and
(a type of Asexual
• SEXUAL REPRODUCTION = involves 2
parents who combine their DNA to
produce a new organism. The new
organism is different from both of the
• CONJUGATION = the process where 1
bacterium gives some of its DNA into
another bacterium through a thread-like
1.Conjugation results in bacteria with new
combinations of DNA.
• Then, when the bacteria reproduce by
Binary Fission, the resulting daughter
bacteria have the new DNA in them.
2. Conjugation results in genetically different
bacteria cells, not an increase in the
number of bacteria cells.
• These NEW bacteria may be more fit to
survive than the parent bacteria.
Unfavorable conditions for bacteria growth
1. No food
2. No water
3. A huge change in temperature
• An ENDOSPORE = a small, rounded,
thick-walled resting cell that forms inside a
bacterial cell. It contains the DNA and
• The formation of an Endospore allows the
bacterium to stay alive in terrible
conditions for years. Once the terrible
conditions get better, the bacterium can
begin to grow and reproduce again.
• Its kind of like HIBERNATION.
THE ROLE OF BACTERIA IN
GOOD THINGS BACTERIA DO:
1. Make Oxygen
2. Make Food
3. Environmental recycling & clean-up
4. Health & Medicine
THE ROLE OF BACTERIA IN
BAD THINGS BACTERIA DO:
1. Cause disease
2. Spoil Food – waste money