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How is the ultrastructure of different cells related to their functions?
Each cell in existence has different structures that aid them in functioning efficiently. Cell
structure can be defined as the components a cell has which help it to perform its different functions.
The relation between ultrastructure of a cell and its function is in terms of the organelles present,
size, shape etc.
Components of a cell such as the nucleus, cell membrane and the cytoplasm are present in
every cell and in most cases serve the exact same functions. However other components of the each
type of cell are specialised to order to work as efficiently as possible.
For instance; the red blood cells which transport oxygen around the body and carbon
dioxide out of the body has specialised structures which enable it to transport resourcefully and
quickly. The biconcave shape of the red blood cell provides it with a large surface area to volume
ratio. The larger the surface area to volume ratio means that the oxygen bonds to the haemoglobin
faster. The shape of the red blood cell also allows them to travel through any vessel; meaning that
because they are small and rounded they can pass through even the smallest capillary. The
haemoglobin; which is the oxygen carrying protein in the blood cell, aids the carrying of oxygen in the
blood, the fact that the red blood cells have more room to carry haemoglobin. It also has a thin
membrane that allows easy diffusion to occur.
If the red blood cells weren't specialised in this way they wouldn't be able to transport
oxygen around the body efficiently. The muscles that require oxygen wouldn't be able to work as
they can no longer respire in order to produce energy. For example if the red blood cells had just a
regular circular shape they would be unable to fit through small capillaries and wouldn't be able to
travel as quickly. People with sickle cell anaemia have abnormally shaped red blood cells, in contrast
to the biconcave shape of the regular red blood cells, they have a crescent shape. This makes the red
blood cells more vulnerable to getting stuck in small capillaries and also breaks into pieces which
disrupt the flow of blood to the body restricting the amount oxygen being transported around the
body. The shape of the red blood cell also restricts the amount of oxygen it can carry further
reducing the oxygen concentration it delivers to the body.
Nerve cells also have special adaptations that allow them to transport messages to the next
nerve cell in order to send information across the body. Nerve cells have a very long axon meaning
that can deliver messages a long distance. The axon is surrounded by a myelin sheith (fat containing
cells, insulating layer) which conducts the impulses by saltatory conduction; a process which assists
the transmission of an impulse along an axon, when the current reaches an area where there are no
fat containing cells on an axon, and must jump across the strip. The myelin sheith contains an organelle
called the nodes of Ranvier which have concentrated sodium channels which allows the impulse to
jump from node to node. This increases the speed of the impulse sending the message faster. The
synapse at the ends of the nerve cells ensures that the impulse can only travel in one direction. The
presynaptic cleft produces a chemical neurotransmitter which stimulates the receptors on the post
synaptic cleft and so therefore the impulse can only travel in one direction. Some nerve cells can
undertake summation, where several nerves synapse to the same neuron (such as in the eye).
Without the specialised structure of nerve cells they would be unable to transmit impulses
around the body so quickly meaning that information cannot be sent around the body as quick as it
might need to be sent. For example if the axon weren't very long it would take longer for the
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impulse to travel. Also if there were no synapses the impulses may travel the wrong way sending the
message back instead of forwards. For instance if someone was to burn their hand a message would
be sent quickly to remove the hand from the hot item to prevent further damage, if this message
wasn't sent quick enough, there would be a lot more damage done. Similarly if the impulse travelled
the wrong way it would also take longer.…read more
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The ultrastructure of cells allows them to carry out their functions efficiently. If all cells were
the same no organism would be able to survive as the cells would be incompetent and would be
unable to carry out any of their functions properly.…read more