Name: Marion Paxton Diffusion Lab Introduction: In this lab you will observe the diffusion of a substance across a semi permeable membrane. Iodine is a known indicator for starch. An indicator is a substance that chances color in the presence of the substance it indicates. Watch as your teacher demonstrates how iodine changes in the presence of starch. **Prelab Observations: Describe what happened when iodine came into contact with starch. The cornstarch turned blue-black Procedure:
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The Lipid Barrier of the Cell Membrane‚ and Cell Membrane Transport Proteins The structure of the membrane covering the outside of every cell of the body is discussed in Chapter 2 and illustrated in Figures 2–3 and 4–2.This membrane consists almost entirely of a lipid bilayer‚ but it also contains large numbers of protein molecules in the lipid‚ many of which penetrate all the way through the membrane‚ as shown in Figure 4–2. The lipid bilayer is not miscible with either the extracellular
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The effect of size on the effectiveness of diffusion Aim: To use agar blocks infused with 0.1 Molar sodium hydroxide (NaOH) and phenolphthalein to investigate the relationship between shape and surface area: volume ratio on the effectiveness of diffusion. Hypothesis: That for a cube of agar‚ the time taken for complete colourisation due to diffusion of HCl is directly proportional to the cubes volume. Materials: |A block of agar (10cm x 5cm x 3cm) with 0.1M NaOH and |1x 250mL
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things. One important part of a cell is the cell membrane. The cell Membrane is a thin protective coating around a cell that regulates what goes in and out of the cell. An important part of regulating this is passive transport. Passive transport is the movement of materials through membranes without any input of energy. One type of passive transport is diffusion. Passive transport is the diffusion of substances across a membrane. In diffusion‚ molecules will usually move from where the substance
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Diffusion Introduction Diffusion is the net movement of ions or molecules from a region of high concentration to a region of low along the concentration gradient until equilibrium has been reached. The steeper the gradient the faster the rate of diffusion. There are a few types of diffusion. Three (3) of those are: Facilitated Diffusion- refers to diffusion of substances across a cell membrane with the help of transport protein. Dialysis- refers to the diffusion of solutes across a semipermeable
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Ronald Wilson Pd:4th 11/16/12 Introduction In this experiment diffusion and osmosis is the main idea. When using diffusion and osmosis you are trying to separate different solute concentrations on either side of the membrane. Only a solute’s relative concentration‚ or water potential‚ affects the rate of osmosis. The higher the concentration of solutes‚ the faster water will flow through the membrane to equalize the concentration. The way we describe the movement from higher to lower concentration
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Diffusion is the process by which a particular phenomenon --- such as a contagious disease‚ a technological innovation or even an idea --- is spread from person to person over a period of space and time. One method of diffusion is known as expansion diffusion‚ which is broken down into three distinct types. Expansion Diffusion * Strictly defined‚ expansion diffusion is the process of spreading something from one place to another in an ever-expanding "snowballing" process. Expansion diffusion
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Scientific Paper on Diffusion 2 ABSTRACT The effect of molecular weight on the rate of diffusion was assessed using two tests: the glass tube test and the agar-water gel test. In the glass tube set-up‚ two cotton plugs soaked in two different substances (HCl and NH4OH) were inserted into the two ends of the glass tube. The substance with the lighter molecular weight value (NH4OH‚ M = 35.0459 g/mole) diffused at a faster rate (dAve = 25.8cm)‚ resulting in the formation of a white ring around the
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The cell‚ which is the smallest unit of life‚ is surrounded by a plasma membrane. The plasma membrane functions somewhat like a wall‚ as it keeps the internal contents from the external environment. Just like a wall‚ the membrane is also somewhat permeable‚ except that the membrane takes a much more active role in determining what is allowed in to the cell and what is kept out. The plasma membrane is a very thin structure‚ which has some very important tasks. One of the main tasks that it performs
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process of diffusion of substances across a semipermeable membrane to gain a better understanding of how cells move materials across cell membranes. The experiment was designed to exhibit Brownian Motion; the random movement and tendency of particles of a substance to move from an area of greater concentration to lower concentration via diffusion until equilibrium has been attained. In addition to observing the passive process of diffusion‚ the experiment demonstrated how a semipermeable membrane will
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