In experiment 1, the exchange of substances, through passive transport, was observed. In this experiment, a dialysis membrane was used to simulate a cell membrane, however, the dialysis membrane is not alive. In addition, the dialysis membrane is semipermeable meaning that, depending on size, only certain substances will be able to go through. During the experiment, the membrane was half filled with glucose and, the other half, filled with starch solution. The membrane was placed into a beaker with iodine solution. The hypertonic concentration of iodine on the outside of the membrane leads to diffusion, which, if they are small enough, will move the molecules towards the hypotonic area (inside membrane). As diffusion moved the iodine from the beaker into the membrane, the white color of the starch and glucose solution inside the membrane turned blue/purple. That happened because, as iodine comes in contact with starch, it reacts and turns blue/purple, proving that iodine was small enough to go through the semipermeable membrane. On the inside of the membrane, there was a …show more content…
After that, the plant was placed on a slide and, instead of dropping a drop of water, a drop of the 10% salt solution was dropped on the plant. When placed under the microscope, it was observed that the chloroplasts were tightly packed in the middle of the cells. The 10% salt solution was hypertonic, while the cell was hypotonic, because of that, salt moved, through diffusion, to the inside of the cell, so that equilibrium could be reached. Also, the water from the cell, through osmosis, went from the hypotonic cell to the hypertonic solution. As the water leaves the cell, the volume decreases, and the cell shrinks. However, the rigidness of the cell wall, does not allow it to shrink, so, what happens is that the inside of the cell shrinks while the cell wall maintains itself
Two members of the group were instructed to visit the laboratory each day of the experiment to water and measure the plants (Handout 1). The measurements that were preformed were to be precise and accurate by the group by organizing a standardized way to measure the plants. The plants were measured from the level of the soil, which was flat throughout all the cups, to the tip of the apical meristems. The leaves were not considered. The watering of the plants took place nearly everyday, except for the times the lab was closed. Respective of cup label, the appropriate drop of solution was added to the plant, at the very tip of the apical meristems.
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.
Sill P - Planning Prediction I predict that as the concentration of salt solution (molar dm-3) is increased, meaning that the water potential outside the carrot decreases, the water potential inside the carrot will decrease. As the water potential outside of the carrot cell is decreased, the water potential inside the carrot will increase, when the salt solution is more dilute. This change in water potential will occur because of a net movement of water molecules called osmosis. Osmosis is; The movement of water molecules from an area of high water potential to an area of low water potential, down the concentration gradient, across a partially permeable membrane. A partially permeable membrane, which is found in plant cells, such as the ones in a carrot, is a membrane that only allows certain molecules to pass through it, in this case, the membrane will allow water molecules to pass through it, but will not let the salt molecules pass through.
Plasmolysis However when the plant cell is placed in a more concentrated solution the water inside the cell passes out the cell. The cytoplasm... ... middle of paper ... ...
When I dropped iodine to the leaf where I split off from the plant which had waited in red light, its color changed into blue. However, when I dropped iodine to the leaf where I split off from the plant which had waited in green light, its color stayed the same. It is because the plant waited in red light could make more photosynthesis than the other one, so it has more glucose and an iodine solution makes substance’s color blue if it has starch. It is used to test the presence of starch.
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 ...
Osmosis in Carrots Background Osmosis is the diffusion of water from a dilute solution to a more concentrated solution through a partially permeable membrane, which allows the pass of water molecules but not solute molecules. [IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE]If a cell is placed in a less concentrated solution water enters because the less concentrated solution will have a high concentration of water than the inside of the cell. Once the cell takes in maximum water the cell becomes turgid. If the cell was to be placed in a high concentrated solution, water would leave the cell because the cell would contain a low concentrated solution. So in the low concentrated solution there will be a high concentration of water and in the high concentrated solution there will be a low concentration of water.
The experiment is aimed at giving a better understatement of osmosis process and the different conditions in which osmosis occurs.
Osmosis is a type of diffusion which is only applied on water and is a passive process which does not require an input of energy from the cell; this is because materials are moving with the concentration gradient. Osmosis is a process that occurs at a cellular level, which entails the spontaneous net movement of water through a selectively permeable membrane, from a region of high to low water concentration, in order to equalise the level of water in each region. This form of diffusion takes place when the molecules in a high concentration are too large to move through the membrane. The term semi-permeable or selectively permeable means that some substances can easily pass through the cell membrane, whereas others cannot. The significance of osmosis to cells is great, since it is the osmotic pressure that maintains the shape of an animal cell and provides support in the plant cells. Many factors affect the rate of osmosis including size of particles and temperature however in this particular experiment the factor investigated is the concentration of sodium chloride. Tubes of potatoes will be used to demonstrate the fact...
Investigate the Osmosis of Potato Cells in Various Salt Solutions. Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. I will be able to change the input of my experiment. The input variable is the concentration of the solution.
If a plant cell is places in a hypotonic solution the cell has a lower water concentration to that of the solution. Water will move into the cell by osmosis from a high water concentration outside the cell to a lower water concentration inside the cell through a selectively permeable membrane. The cell becomes turbid
On a cellular level, Mrs. Jones’ cells are dehydrated due to osmotic pressure changes related to her high blood glucose. Cells dehydrate when poor cellular diffusion of glucose causes increased concentrations of glucose outside of the cell and lesser concentrations inside of the cell. Diffusion refers to the movement of particles from one gradient to another. In simple diffusion there is a stabilization of unequal of particles on either side of a permeable membrane through which the particles move freely to equalize the particles on both sides. The more complex facilitated diffusion is a passive transport of large particles from a high concentration of particles to a lower concentration of particles with the aid of a transport protein (Porth, 2011). The cellular membranes in our bodies are semipermeable allowing for smaller molecules to flow freely from the intracellular to extracellular space. The glucose molecule, however; is too large to diffuse through the cellul...
However, the solution could be more water than salt so the water from the solution could be more concentrated than the water inside the potato cells. If so then In theory the water in the solution should diffuse into the potato. cells and increase in mass. Apparatus: Potato to perform the experiment on. Thin metal tube to cut potato chops with.
Osmosis is a biological process. If equilibrium is ever achieved, then water molecules will move. back and forth between the substances. If a surrounding sucrose solution has a lower water potential than the plant tissue in the solution, then, through osmosis water will move from the tissue into the. the surrounding solution, the tissue will lose mass and length as a result.
== = This experiment is based on the concept of Osmosis. Osmosis is the diffusion of water molecules from a region of high water concentration to a low water concentration through a semi permeable membrane (in this case, the cell potato cell membrane). The cell walls of the potato cells are semi permeable meaning that water molecules (which are small) can fit through but other bigger molecules such as glucose cannot pass through. The water molecules can flow both ways through the membrane, letting molecules both in and out.