Download 3. Bacteria - la068.k12.sd.us

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Bacteria
How do bacteria reproduce?
 Binary
Fission
A
form of asexual
reproduction
 The
daughter cells
are identical to the
parent cell.
 Genetic
material is
copied and split into
two different cells.
How big are bacteria?
 About
1 μm in diameter. (1 micrometer)
 Putting
it in perspective-
hair is 100 μm in diameter
 A grain of salt is 1,000μm wide
 Your
Why is a small size necessary?
 Small
size is extremely important because
it allows for a large surface area-to volume
ratio.
A
small volume but large surface area
allows for the bacteria to get rid of waste
and absorb nutrients faster.
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What protects bacteria from
the outside world?

Cell Wall

Just like plants, bacteria have a
cell wall to protect them from
the elements.

Some bacteria have a capsule
or slime layer for extra
protection.

Endospore- many bacteria
have a spore within the cell
wall that they can reduce to in
tough environments
How do bacteria move?
 Flagella!
 Move
like the motor
of a boat.
• Some bacteria have
pilli, which are
projections that
help bacteria to
hold onto surfaces.
What is unique about bacterial DNA?
 It’s
A
circular!
bacteria’s entire genome is on one circle of DNA
 Bacteria
also have plasmids which can pass between
bacteria. This allows for a drug-resistant bacteria to
pass it on to other bacteria.
Does bacteria have a nuclear
membrane?
 NO!
Prokaryotes don’t have a true
nucleus.
 Bacterial
nucleoid.
DNA is usually localized in the
Why is bacteria important to farmers?
 Bacteria
can change
ammonia (from
fertilizer) into nitrate
(used by plants.)
 Some
bacteria like
Rhizobium live on the
roots of legumes (like
soy beans) and are
able to put nitrogen
back into the soil.
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Whiteboards
 You
have seen many pictures of bacteria
throughout the power point. On your own,
try to draw a bacteria cell on your
whiteboard and label the important parts.
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Did it look like this?