Cellular Energy Essay
The semi-permeable membrane of a cell's membrane is a highly selective barrier. A cell membrane uses a combination of diffusion, osmosis, facilitated diffusion, and active transport to move materials in or out of the cell in order to maintain proper concentrations on both sides of the membrane. Diffusion is the movement of materials from an area of greater concentration to an area of lower concentration until equilibrium is reached. Osmosis is the same as diffusion accept with water. Facilitated diffusion occurs in living cells only and is used to transport matter in through the cell membrane that is either to large to diffuse or is charged. Facilitated diffusion moves materials through an integrin transport protein from an area of higher concentration to an area of lower concentration. Active transport requires ATP. Active transport moves materials from an area of lower concentration to an area higher concentration (against the concentration gradient).
Energy is the capability of something to do work. Work is to move matter in a direction it would not normally go in when left alone. There are two groups that different forms of energy fall into; energy is either potential or kinetic. Potential energy is energy that is stored. It has the capacity to preform work as a result of location or arrangement. An example of potential energy would be the energy that is stored in the molecular bonds of the molecule ATP. Kinetic energy is the energy of motion. Moving molecules or atoms have kinetic energy. An increase in thermal energy would mean that the molecular movement of a substance has increased. A covalent bond is when electrons are shared between atoms to make a total of eight in the outer shell. The amount of energy that it takes to form covalent bonds is exactly the same as the energy needed to break the bond. Part of the energy that is stored in these bonds is based on the two atoms that are bonded. If one atom has a very high electronegativity and the other has a very low electronegativity, than the bond that forms between these two atoms will have a higher potential energy. If the electronegativity is about the same the potential energy stored in the covalent bond will be lower. Going back to the example of ATP as potential energy, the three phosphates bond's contain the primary energy in the ATP molecule. When cells use ATP energy is released from the bonds when a phosphate group is broken off.
The best way I learned about diffusion and osmosis was the lab that was conducted in class with dialysis tubing. I thought it was very interesting how diffusion and osmosis directly affect each other. When glucose diffused into the dialysis tubing it caused the water to leave the tubing through osmosis. It was also interesting to see that the starch which could not diffuse through the tubing did not affect the glucose diffusing or the water in osmosis. The concept of proving that one molecule is larger than the other seemed difficult to achieve at first but the data that was produced accurately supported the hypothesis that had been created.
I learned the most about energy in covalent bonds from my notes on energy that were taken in class. They provided accurate and straight to the point facts that were very useful because I was able to link them to what I had already learned about covalent bonds. I also had a lot of prior knowledge on energy forms from personal research that I had done previously after reading an article on perpetual energy devices.
The knowledge that I have acquired during this unit of study has helped me to clearly understand how energy moves naturally and how everything either is or requires energy in order to do something (work). Going beyond the information that was learned for this unit, I also learned more about problem solving and figuring things out based on what information is given. The dialysis lab was the origin of this development. During the lab, there were a few points where I felt as though I was on the wrong track or something was not working right but when I looked at all of the information that was collected from the experiment together I realized what it meant. This unit will help me to be more successful in the future not only from the information but also from the experience of learning it.