|What is the function of the folds within the
|Question Date: 2016-06-08|
A folded surface has more surface area than a
flat surface. Imagine an accordion, which
looks small when it’s bunched up, but actually can
be stretched out due to its folds. So,how does
this relate to the mitochondria?
Inside the mitochondria, chemical reactions occur
which produce energy for the cell. One of these
reactions happens at the folded surface of the
inner membrane. Before the reaction can occur,
charge is transported across this membrane,
similar to charging a battery. This charge then
allows the energy-producing reaction to happen.
Since the reaction happens at the membrane
surface, a folded membrane with increased
surface area can produce more energy for the cell.
They increase the surface area of the inner
membrane, allowing there to be more proteins and
more exchange of ions across the membrane,
allowing the mitochondrion to do its job more
The function of the folds within the
mitochondria is to increase the surface area of
the mitochondrial membrane. Basically, the
physical form of a structure can increase or
decrease its surface area to volume ratio. For
instance, a sphere has the minimum surface area to
volume ratio, whereas a pyramid has a larger
surface area to volume ratio. For example, if you
had a fixed volume of clay and made it into
a sphere or a pyramid, the pyramid would have a
larger surface area.
The same concept applies to mitochondria that
by having a highly folded structure, they increase
the surface area of their membrane.
The reason mitochondrial membranes need a high
surface area is because the process of using
oxygen to make energy is carried out on this
membrane. The larger the surface area of this
membrane, the more room for the membrane-bound
cellular machinery that uses oxygen to make
energy. Therefore, for a cell to make energy
at a high rate, the folds are necessary.
The function of the folds in mitochondria is
to increase the surface area. This inner
folded part of the mitochondria (the inner
membrane) is responsible for cell respiration (the
process of breaking down carbohydrates (sugars) to
make energy). Part of cell respiration happens by
transferring molecules across the inner membrane,
so by adding folds, a longer piece of membrane
can be stuffed inside the mitochondria. This
increases the amount of molecules that can be
transferred across it.
Increasing surface area can be seen in many other
parts of the body too. For example, absorption of
nutrients in our digestive system happens in the
small intestine. Nutrients have to be moved across
the wall of the small intestine to be absorbed. We
increase absorption by making the intestine really
long, but on the inside it is also very folded (in
structures called "villi") which increases
the surface area so more absorption can occur.
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