When a substance is released into an area, the random movement of its molecules results in a multitude of collisions. These collisions, in turn, lead to a dispersion of the molecules. The overall movement of the molecules will be from an area of high concentration, where there will be more collisions, to areas of low concentration, where the number of collisions will be much less. This process of dispersion will continue until there is no net gain or loss of molecules in an area. The process by which this equilibrium occurs is called diffusion. Diffusion is vitally important to biology on many levels; individual cells, organelles, and even whole organisms rely on diffusion to carry out the processes essential to life. One especially important aspect of diffusion is osmosis, or the diffusion of water. This often occurs across a semi-permeable membrane…
1. The cell membrane regulates and controls what kind of molecules ______ move in & out of the cell.…
2. Purpose: The purpose of this lab is to help give visual understanding of diffusion which is a solution of high concentration spontaneously (no energy required) moving to an area of low concentration. Also taking a look at osmosis, which is the movement of chemicals across the cell membrane. Osmosis requires some type of energy to be put in for this to happen. After these experiments we should have a better idea and visualization of how chemicals transfer across the cell membrane.…
Purpose: The purpose of this lab is to familiarize you with osmosis and, specifically, what happens to cells when they are exposed to solutions of differing tonicities.…
Seal the end if it is not already closed. Next, pick up a pipette and fill it with glucose. (Use this pipette only for glucose) then release the glucose into the dialysis tubing. Place four more pipettes full of glucose into the dialysis tubing. Now it is time to get another pipette (not the one used for glucose) and fill it with starch and release it into the dialysis tubing. Repeat this 4 (four) more times until there is a total of 5 pipettes of glucose and 5 pipettes of starch in the dialysis tubing. Mix the solution. Next, seal the dialysis tubing completely and make sure there is little to no air left in the dialysis tubing. Rise the bag with water. Next, fill a 400ml beaker with 300ml of water. Add 5 pipettes of Lugol´s into the 300ml of water. Mix the solution gently. Place the dialysis tubing bag into the 400ml beaker and leave for 30 minutes. After 30 minutes remove the bag and record your findings. Get 3 test tubes and label them “control” “bag” and “beaker” Next fill an unused pipette with water and pour it into the control test tube. Open the dialysis tubing and fill a pipette of the solution inside using an unused pipette. Repeat again and pour into the bag test tube. Place two pipettes of the beaker solution into the beaker tube. Add one pipettes of Benedict´s into each tube Heat all tubes for three minutes. Record…
Active Transport within a cell membrane requires the use of energy and moves molecules from low to high concentrations using protein carriers. Types of active transport include:…
Diffusion is the molecular net movement from a higher concentration to a lower concentration. For instance, when a person is smoking, the smoke diffuses into the air. The molecules in the smoke, released from the cigarette, travel through the air. Here is how it occurs. When molecules are close enough, they collide with each other, their kinetic energy changes. Due to the direct relationship between diffusion and molecular kinetic energy, the molecules move away from the point of the collision as their kinetic energy is redirected. Therefore, molecules always tend to distribute themselves throughout the area they stay. It continues until dynamic equilibrium is reached, that is, no net movement happens. Molecules at that time are still in motion, but the amount of molecules moving in one direction equals to the amount of molecules moving in the other direction.…
active transport: the movement of molecules across a membrane that requires the expenditure of cellular…
In this lab we will look at how molecules move across the membrane of a cell . Osmosis is the movement of water across a cell membrane.In osmosis the cell membrane is selectively permeable,which allows for the membrane to control what types of substances that passes through.Transportation can either be passive or active.Passive transport does not require the use of added energy where as active transport requires the cell to use energy.…
Purpose: The purpose of this activity is to determine the effects of a selectively permeable membrane on diffusion and osmosis between two solutions separated by a membrane.…
Change the objective lens for a higher magnification on your sample (x10, x40, x1000) as to make out things such as its nucleus.…
The purpose of this lab was to observe the rate of osmosis and diffusion, as well as the effect of molecular size of the particles on this rate. Part I of the lab was a demonstration of osmosis and diffusion, that dealt with raisins in different liquid environments, each with a different concentration of sugar. Part IV of the lab was using the same idea as the demonstration, by putting objects in different concentrations of a substance; in this case elodea leaves in salt water. In both cases, the objects in a greater concentration of the substance were stripped of their water. However, where there was a little or no concentration of sugar or salt, the objects did not lose their water, and in the case of the raisin, became saturated with excess…
Osmosis is the diffusion of a solvent across a selectively permeable membrane that occurs in response to differences in solute concentrations (Allen and Harper 2014).Osmosis can fall under the category of passive transport which does not require energy. With osmosis being a type of diffusion it is viewed as molecules moving from a high concentration to a low concentration. To further explain if there is a low water concentration, high amounts of solutes will be present. Water will most likely move to areas where the solute concentration is high, which demonstrates why there would be less water concentration.…
In the initial set up of this experiment I had 2 sets of 3 screw-cap test tubes that had each been half-filled with 5% gelatin and 1-mL of the correct dye (either potassium dichromate, aniline blue, or Janus green) in each of the test tubes. I labeled the 3 test tubes of set 1 with which die they contained and marked them “5 ˚C”. Then with the other set I did the same exact thing, except I labeled these test tubes “Room Temperature”. I then placed set 1 of the test tubes in a 5˚ C refrigerator, while I kept set 2 at room temperature for a certain amount of time. I made sure to record the time I began the experiment in my lab manual. To begin, I removed set 1 from the refrigerator and compared the distance the dye had diffused in each of the 3 test tubes with the corresponding test tubes of set 2 that had been kept at room temperature. Next, I held each tube vertically in front of a white sheet of paper, and then used a metric meter to measure how far the dye had diffused from the gelatin’s surface (in millimeters). I then recorded each of these distances in my lab manual. I repeated this step for each of the test tubes in both set 1 and set 2 and recorded my results. Then, using my results, I calculated the rate of diffusion for each dye by using this formula: rate of diffusion = distance/ elapsed time (hours). Each of these calculations was then also recorded in my lab manual. I made sure I noted the time the experiment started, ended, and the total elapsed time in hours in my lab manual as well.…
mass of the potatoes got lower, but the graph did not end up as a…