Alison Crist
10/18/15
Period 6
In order to maintain homeostasis, cells must produce energy by allowing the necessary nutrients into the organelles while eliminating wastes that could be harmful to them. The cell membrane is also known as the phospholipid bilayer because of the fact that there are two layers formed by phospholipid molecules. The phospholipid has a phosphate and a lipid portion. "The phospholipids lie with their hydrophilic heads at the membrane surface and their hydrophobic tails on the inside..." (Anatomy and Physiology Textbook 66) There are two general membrane proteins, including the integral proteins, also known as transmembrane proteins. These proteins act as transporters, channels and receptors. "Integral proteins are …show more content…
Diffusion is the movement of solutes and is a passive transport where particles move from higher concentration regions to lower. The cell membrane selectively restricts diffusion so ions move across the membrane by crossing the lipids or going through a channel. "Alcohol, fatty acids, and steroids can enter cells easily, because they can diffuse through the lipid portions of the membrane." (Anatomy and Physiology Textbook 86) The rate of diffusion is affected by surface area available and temperature because it affects the way that the partials move. Although osmosis may seem similar to diffusion, it's this whole other transport. Osmosis is the diffusion of a substance through the membrane from a reduced solution to a concentrated solution. "Some solutes diffuse into the cytoplasm, others diffuse out, and a few (such as proteins) are unable to diffuse across the cell membrane at all." The pressure that moves the water into and out of the cell is water potential. Solutes in the cell lower the water potential so cells have a lower potential than pure water. An example of osmosis would be the absorption of water by plant roots. The passage of molecules through the cell membrane is mediated by carrier proteins in the membrane. Specificity, saturation limits, and regulation are all involved in carrier- mediated transport. Some carrier mechanisms move more than one substance at a time. "Symport, the carrier transports two substances in the same direction...into or out of the cell...antiport, one substance moves into the cell and the other moves out." Each molecule has a specific carrier protein to assist in getting it across the membrane. Vesicular transport is when a cell confines extra cellular materials in an infolding of the membrane to form a vesicle, which then gets moved across the cell to expel of
10/18/15
Period 6
In order to maintain homeostasis, cells must produce energy by allowing the necessary nutrients into the organelles while eliminating wastes that could be harmful to them. The cell membrane is also known as the phospholipid bilayer because of the fact that there are two layers formed by phospholipid molecules. The phospholipid has a phosphate and a lipid portion. "The phospholipids lie with their hydrophilic heads at the membrane surface and their hydrophobic tails on the inside..." (Anatomy and Physiology Textbook 66) There are two general membrane proteins, including the integral proteins, also known as transmembrane proteins. These proteins act as transporters, channels and receptors. "Integral proteins are …show more content…
Diffusion is the movement of solutes and is a passive transport where particles move from higher concentration regions to lower. The cell membrane selectively restricts diffusion so ions move across the membrane by crossing the lipids or going through a channel. "Alcohol, fatty acids, and steroids can enter cells easily, because they can diffuse through the lipid portions of the membrane." (Anatomy and Physiology Textbook 86) The rate of diffusion is affected by surface area available and temperature because it affects the way that the partials move. Although osmosis may seem similar to diffusion, it's this whole other transport. Osmosis is the diffusion of a substance through the membrane from a reduced solution to a concentrated solution. "Some solutes diffuse into the cytoplasm, others diffuse out, and a few (such as proteins) are unable to diffuse across the cell membrane at all." The pressure that moves the water into and out of the cell is water potential. Solutes in the cell lower the water potential so cells have a lower potential than pure water. An example of osmosis would be the absorption of water by plant roots. The passage of molecules through the cell membrane is mediated by carrier proteins in the membrane. Specificity, saturation limits, and regulation are all involved in carrier- mediated transport. Some carrier mechanisms move more than one substance at a time. "Symport, the carrier transports two substances in the same direction...into or out of the cell...antiport, one substance moves into the cell and the other moves out." Each molecule has a specific carrier protein to assist in getting it across the membrane. Vesicular transport is when a cell confines extra cellular materials in an infolding of the membrane to form a vesicle, which then gets moved across the cell to expel of