A cell wall is a structural layer that surrounds some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides cells with both structural support and protection, and also acts as a filtering mechanism. Cell walls are present in plants, fungi and prokaryotic cells, where a major function is to act as pressure vessels, preventing over-expansion when water enters the cells. Cell walls are absent from mycoplasmas.
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Pathogens are bacteria, viruses, parasites, and fungi that
cannot be seen by the naked eye, be tasted by our sense of taste, nor be
smelled by our noses. These microorganisms’
causes illnesses, especially to their host, the host serves as their food,
shelter and victim. Pathogens are found in wastes, such as hospital wastes or
in the sewages. Pathogens are mostly parasites, which is why they need a host
to survive.
Coughing and sneezing are reflexes of the body
that prevent bacteria to further damage the organs inside the body. It helps in
keeping the airways clear and in healing. The two sources or passages of these
natural reflexes are the nose and the mouth.
<span>
Inside the nose, there are nasal hairs present to
filter the oxygen or air that we breathe in. These are called Cilia, these are
protective mechanisms of the body that trap dirt that cannot pass through the
respiratory system. Sneezing is a natural reflex that clears the nose passages
from obstructions that might affect the lungs. Coughing is also a natural
reflex that is generated by an irritation in the tonsils, this condition is
commonly viral. The tonsils are responsible for protecting the passage of dirty
air into the lungs.</span>
