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Slide 1

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Bacteria…read more

Slide 2

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The flagellum moves the
bacterium by rapid rotations.
The cell wall prevents the cell
swelling and bursting.
The capsule covers the cell
markers on the cell
membrane which identify
the cell. This way the The pili are protein-like
bacterium is not identified projections used for
by the immune system. attachment to a host cell
and for sexual
reproduction. They also
make the bacteria more
vulnerable to viral
infection.…read more

Slide 3

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The contents of bacterial
cells are usually hypertonic
, so water moves in by
The cell wall
Has a layer of peptidoglycan which is made
up of many parallel polysaccharide chains
with short peptide cross-linkages.
It maintains the shape of the bacterium.
Gives support and protection to the contents
of the cell.…read more

Slide 4

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aureus is an
Gram-positive bacteria
Has a THICK layer of peptidoglycan
Has teichoic acid
The crystal violet in the stain binds to
the teichoic acid and resists
The cells appear PURPLE…read more

Slide 5

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E. coli is an
Gram-negative bacteria
Cell walls have THINNER layer of peptidoglycan
NO teichoic acid
An outer membrane-like layer made up of
Any crystal violet which doesn't bind is readily
decolourised and replaced with red safranine in the
Gram stain
The cells appear RED…read more

Slide 6

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Cocci - Bacilli ­ rod Spirilla ­ Vibrios ­ comma
spherical shaped twisted shaped…read more

Slide 7

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Slide 8

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Slide 9

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Slide 10

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This PowerPoint contains clear information and useful diagrams on bacterial structure, sexual reproduction and asexual reproduction. This topic is found in a number of GCE specifications. The slides could be printed off and used as revision cards.

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