Mediaphys Lesson
1. Discuss the structure of the plasma membrane and explain the process of active and passive transport through the membrane.
The Cell or plasma membrane is not a solid structure, but made up of proteins that form channels and pores. In addition, carbohydrate molecules serve as recognition of cells and cholesterol molecules contribute to the stability of the membrane. The structure consists mostly of phospholipid molecules. The membrane separates the interior of all cells from the outside environment.
Active transport requires the use of energy because substances are moved against/up a concentration gradient or across a partially permeable membrane. On the other hand, passive transport moves molecules down the concentration gradient and does not require cellular energy. For example, osmosis which is the movement of water across the membrane would be considered a passive transport because the molecules, or in this case water move easy and freely.
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Osmosis Lab 2. Explain your observations in detail in terms of concentration gradient, diffusion, osmosis, osmotic pressure, passive transport, and active transport. Vinegar contains acetic acid and water. The eggshell (calcium carbonate) separated from the egg due to the acetic acid, exposing the egg cell membrane. Therefore diffusion occurred because water was able to enter inside the egg and made it swell. The water traveled from the jar (high water concentration) into the egg (low water concentration) until both areas have the same concentration, creating a balance (osmosis). This process is a passive transport because it did not require energy input (ATP) and was able to travel down its concentration gradient. On the other hand, placing the same, shell less egg in corn syrup made the egg shrink. An active transport occurred, because the water from the egg moved out into the corn syrup, which required the cell to use energy to move water through the membrane into the syrup. The osmotic pressure of the corn syrup is very low, because it contains mostly sugar and only very little water. Ph.I.L.S Lab 3.
Explain what happened to the blood cells at the various levels of concentration. Be sure to refer to the solutions as being hypotonic, hypertonic and isotonic.
When a red blood cell is placed in hypotonic (very dilute) solution of NaCl some sodium ions may leave the cell. In addition, water enters the cell, and the cell swells, because the concentration of solutes is greater inside the cell than outside of it.
When a red blood cell is placed in hypertonic (very concentrated) solution of NaCl sodium ions may enter the cell, but are pumped out by the Na/K-ATPase pump. In addition, water leaves the cell, and the cell shrinks, because the concentration of solutes is greater outside the cell than inside it.
When a red blood cell is placed in an isotonic solution of NaCl, water neither leaves nor enters the cell; the cell neither swells nor shrinks. The concentration of solutes is the same both inside and outside of the cell and consists of the same osmotic
pressure.
In life, it is critical to understand what substances can permeate the cell membrane. This is important because the substances that are able to permeate the cell membrane can be necessary for the cell to function. Likewise, it is important to have a semi-permeable membrane in the cell due to the fact that it can help guard against harmful items that want to enter the cell. In addition, it is critical to understand how water moves through the cell through osmosis because if solute concentration is unregulated, net osmosis can occur outside or inside the cell, causing issues such as plasmolysis and cytolysis. The plasma membrane of a cell can be modeled various ways, but dialysis tubing is especially helpful to model what substances will diffuse or be transported out of a cell membrane. The experiment seeks to expose what substances would be permeable to the cell membrane through the use of dialysis tubing, starch, glucose, salt, and various solute indicators. However, before analyzing which of the solutes (starch, glucose, and salt) is likely to pass through the membrane, it is critical to understand how the dialysis tubing compares to the cell membrane.
Once the paramedics retrieve Marc, he will have a high concentration of salt in his blood and fluids. This means that the paramedics would treat him with the half normal saline. This is the solution with the lowest percentage of solutes (0.45% NaCl).this will increase his concentration of water throughout this body and will return his cells to their normal size. However, if the paramedics were to keep him on the half normal saline for too long, his water concentration would be too high and his solute concentration would become too low. This would mean that the paramedics would then need to switch Marc to the normal isotonic saline solution (0.9% NaCl). This would balance out both the concentration of water and solutes so that they are now equal. This would set his balance and homeostasis back to normal, thereby helping his recovery. (Johnson
Scientific Theory of Osmosis Osmosis is defined as the solvent of any solution being able to pass through any semi-permeable membrane from a region of high concentration to a region of low concentration until both solutions reach a state of equilibrium. This means that water can flow through a porous material, such as a cell wall or visking tubing, in order to balance the levels of concentration. The molecules are then randomly distributed throughout the solution. Water particles are small and can therefore easily fit through the material; however, larger particles such as salt or glucose are too big to fit through the material. Osmosis has a significant effect on living cells.
Activity 3: Investigating Osmosis and Diffusion Through Nonliving Membranes. In this activity, through the use of dialysis sacs and varying concentrations of solutions, the movement of water and solutes will be observed through a semipermeable membrane. The gradients at which the solutes NaCl and glucose diffuse is unproportional to any other molecule, therefore they will proceed down their own gradients. However, the same is not true for water, whose concentration gradient is affected by solute ...
In osmosis, water can travel in three different ways. If the molecules outside the cell are lower than the concentration in the cytosol, the solution is said to be hypotonic to the cytosol, in this process, water diffuses into the cell until equilibrium is established. If the molecules outside the cell are higher than the concentration in the cytosol, the solution is said to be hypertonic to the cytosol, in this process, water diffuses out of the cell until equilibrium exists. If the molecules outside and inside the cell are equal, the solution is said to be isotonic to the cytosol, in this process, water diffuses into and out of the cell at equal rates, causing no net movement of water. In osmosis the cell is selectively permeable, meaning that it only allows certain substances to be transferred into and out of the cell.
Red Blood Cells (RBCs) are also known as erythrocytes. There are up to 4.2 - 6.2 million RBCs in a cubic millimetre of blood. They specialize in transporting oxygen around the body. As a result of this RBCs are small and have a biconcave shape to increase their surface are to optimize the amount of oxygen that diffuses across their cell membrane. As well as this RBCs have no organelles other than a cell membrane and cytoskeleton (in mammalian RBCs).
In most case osmosis is the diffusion of water. Osmosis is a physical process in which a solvent moves, without input of energy, across a semi permeable membrane separating two solution of different concentrations. The osmotic pressure is defined to be the pressure required to maintain equilibrium, with no net movement of solvent. Osmotic pressure depends on the molar concentration of the solute and not on it identity. It is the exact amount of pressure required to stop osmosis. The tonicity of a solution refers to the effect on cell volume of the concentration of non-penetrating solutes in the solution surrounding the cell
Dialysis depends on dispersion amid which the portability of solute particles between two fluid spaces is confined, for the most part as indicated by their size. (In infrequently utilized adaptations of dialysis, confinement of dissemination by means of
Lipids and proteins determine the permeability of the membrane, and consequently what gets in and out the cell. Hydrophobic molecules can pass through thanks to the non-polar moieties of lipids that make the
Discussion: The results acquired from the experiment have supported the hypothesis. In the first sample, red blood cell in the isotonic solution (NaCl 0.85%) kept its regular shape. This is because when RBC was placed in an isotonic solution, which is the solution has the same concentration of solutes as the cell, water will move into and out of the cell simultaneously and no net effect will be seen. In the second sample, cell shrank, and crenation occurred in the hypertonic solution (NaCl 10%) because the hypotonic solution has a higher osmosis pressure than the cell, water is going to escape from the cell for decreasing the high concentration of solute in the hypotonic solution. Lastly, in the hypertonic solution (NaCl 10%), cell bloated,
π is equal to the osmotic pressure, V is equal to the cell volume and B is the intracellular solids (Hall). Ponder’s R value is the ratio of intracellular solvent volume to the water in its environment; R=(Vi -b)/W. These two equations are related because Ponder’s R value is a measure of how much of an osmometer a cell is while the van’t Hoff relation shows what the osmotic pressure is, both inside and outside the cell. Overall cell membrane permeability can be measured by Ponder’s R value while the osmotic pressure differentials between the external environment and the internal environment are seen with the van’t Hoff relation (Hall). Cells evolved to become great osmometers, but not perfect osmometers, in order to provide a way for solutes to move along permeable membranes. The van’t Hoff relation permits organisms to live in environments of varying osmolarity because regulating solute concentration within a cell can increase or decrease the cell’s affinity for osmosis (Darnell et al). Ponder’s R value, on the other hand, shows how a cell can never become a perfect osmometer. If a cell could become a perfect osmometer, it could cause cell lysis or shrinkage of the cell (Hall). The avoidance of perfect osmometry can be seen within the human erythrocyte as a small portion of cell water will not take part in an osmotic exchange due to tonicity within its
The red blood cell is a disk shaped cell that is compressed in the center, unlike a normal human cell the red blood cell does not have a nucleus which means that they do not have any DNA. The red blood cell contains hemoglobin, hemoglobin is made of iron and protein. In one red blood cell about 280 hemoglobin. The color of your erythrocytes is due to hemoglobin, when hemoglobin has oxygen it appears scarlet which a red-orange color is. When oxygen has just left the cell it appears a slightly darker color. The red blood cell carries oxygen to your tissues the red blood cell does this so well because oxygen moves so well through the membrane. Also erythrocytes are very flexible so they can move so they can move through narrow capillaries.
Write an essay including diagram/s to describe the structure and mechanism of action of one named integral plasma membrane receptor of your choice (80%). Include a discussion of how the protein interacts with the plasma membrane’s lipid bilayer (20%).
The overall purpose of the experiments in this lab was to introduce the function and structure of the plasma membrane, describe the workings of diffusion and osmosis, and to demonstrate how different factors such as particle size, temperature, and space of diffusion area affect the rate of diffusion. With the results from the experiments, it can be concluded that all of the factors listed do affect diffusion, and there may be many more than are unaccounted for.
Moreover, water moves inside and around the cell by osmotic pressure within each compartment and pulls fluid from one area to the other. The level of osmotic pressure remains approximately the same in ICF and ECF. Osmotic pressure can also be defined as the attraction of water to