Essay On Cell Membrane

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Cells are living things that requires substances to be imported into the cell for growth and repair just as a human, or animal, needs to eat for growth and repair. Unlike the human or animal that has arms, jaws, or external tools to collect and consume food, the basic cell does not have any external appendages to readily obtain the substances it needs. This does not leave the cell without any way to obtain the required substances, obviously otherwise they would all be very short lived, and the ways they obtain substances differ in the required energy and the substance being obtained. Regardless of the way or type of substance, everything need to pass the cell membrane to enter or leave the cell. The cell membrane is composed of different levels…show more content…
These proteins come in two flavors, peripheral and integral proteins(Sadava 108), but both act similar in that they both regulate what goes in and what goes out. Integral proteins can also be trans-membrane proteins that are like gateways for the cell membrane and they are a route in which things from either side of the cell can cross the membrane layer. These trans-membrane proteins do not just let any substance pass through and do either require that the substance entering or leaving be specific, so that the protein can react with it. This would be like a hole on a golf course, golf balls can easily fit inside but a football or basketball can not fit inside. This is assuming that no energy is required for the transportation. Another way that these trans-membrane proteins can transport materials is by active transportation, and this requires chemical energy to help the protein transport the material from one place to another(Sadava 114). The chemical energy can be a signal that the protein receives from any place on the trans-membrane protein. If the cell needs something imported then it can signal the protein from the inside and the protein can react with the outside,
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