GCSE Bacteria, viruses and White blood cells Biology

Biology-Bacteria, viruses and White blood cells on GCSE level round-up

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Biology-Bacteria, viruses and White blood
There are three things which cause diseases: Virus (.e.g. common cold, measles, HIV, diarrhoea,
mumps, flu, smallpox), Bacteria (.e.g. tonsillitis, puenomonia, diarrhoea, TB), Fungi (.e.g. athlete's
Bacteria are able to reproduce on their own:
1. Contents of cell copied
2. Cell divides in two
Viruses are unable to reproduce on their own; the y need a host cell:
1. Virus lands on cell
2. Virus injects with genetic material
3. Genetic material takes over cell and builds new virus particles
4. Cell dies
5. New virus particles escape to infect next cell
White blood cells work by either ingesting (engulfing) or producing anti-bodies:
Every cell has antigens
to identify it if is one of its own,
e.g. all the cells in the human
body have the same antigens
There are two types of
white blood cells which fight
against bacteria:
Phagocytosis: The WBC
(white blood cell) engulfs the
bacteria using enzymes
Lymphocytes: produces
anti-bodies to tackle those
particular bacteria which
either then penetrate the cell wall of the bacteria (viruses don't have cell walls) or send out a
chemical which attracts the phagocytes to come and engulf the bacteria while the anti-bodies keep
the bacteria stationary.
The reason why the same bacteria cannot attack your body after it has been dealt with by the
lymphocytes are because memory cells are produced which store those anti-bodies, therefore if
the same bacteria was to enter the body it
would be dealt with by the memory cells. The
memory cells circulate the body in the blood.
Nonetheless, most bacteria/virus
caused infections have more than one way to
deliver themselves-various bacteria can
cause the common cold for example.
Puerperal fever was caused by
doctors not removing bacteria from hands,
equipment, etc.
Semmelweis found out that 3 times the
number of women was dying in teaching ward
compared to midwives ward.
When a professor got cut by an
instrument which had been used in a surgical
operation and not cleaned, therefore dying of
an infection.
Semmelweis came up with the theory
that there was something on the equipment causing this, this is how the pathogens theory, which

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