"Diffusion - How atoms move through solids" Diffusion means mass transport by atomic motion. The mechanisms of Gases & Liquids is known as random (Brownian) motion and for solids is known vacancy diffusion or interstitial diffusion. Simply we can define diffusion as‚ the movement of particles in a solid from an area of high concentration to an area of low concentration‚ resulting in the uniform distribution of the substance. (Diffusion chapter 5‚ 2008‚ p.1) Ronald D. Kriz(1999) suggests that
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Investigation: A factor that affects the movement of water in and out of cells. Osmosis: movement of water from a region of high water potential to a region of low water potential through a partially permeable membrane. High water potential = lots of free water molecules‚ low solute concentration Low water potential = very few free water molecules‚ high solute concentration Factors That Affect the Movement of Water in and out of Cells * Solute concentration * If one solution
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Abstract This investigation was undertaken in order to observe the effects of changing the temperature of the solution that a potato cube is placed in. The temperatures that were tested in this investigation were 0°C‚ 20°C (room temperature)‚ and 70°C. This investigation tested the hypothesis: The rate of osmosis will increase as the temperature increases 2x2x2cm cubes of potato were weighed and then placed into 100mL of 10% NaCl solutions for 10 minutes. After 10 minutes the cubes were again
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Multiplication of contaminant bacteria in urine and interpretation of delayed culture. Abstract A prospective study of the bacterial populations of non-infected urine was mounted in an attempt to define the length of delay between voiding and analysis during which culture would not give false positive results due to the multiplication of contaminant bacteria present at the time of voiding. The findings suggest that culture of urine within four hours of voiding is likely to give a true indication
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Abstract The objective of this experiment was to test the effect of a specialized type of diffusion called osmosis‚ “which involves in selective transport of water molecules across a selectively permeable membrane” (Lab Manual 2nd edition). It was hypothesized that osmosis will occur when there is an uneven distribution of solute in a solvent. The more abundant the solute is in solvent‚ the higher the rate of osmosis through the diffusion gradient forming a hypertonic or hypotonic solution. Solvent
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Simple diffusion The term simple diffusion refers to a process whereby a substance passes through a membrane without the aid of an intermediary such as a integral membrane protein. The force that drives the substance from one side of the membrane to the other is the force of diffusion. In order for substances to pass through a cell membrane by simple diffusion it must penetrate the hydrophobic core of the phospholipid bilayer. The types of molecules that can do this are themselves substantially
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| Stage 2 Biology | | Adelaide High School | [Osmosis Practical Report] Abstract: | The purpose of this investigation is to see if the concentration of Sodium chloride (NaCl) solution will affect the mass of the potato cylinder hence the rate of osmosis. This can be done by placing 5‚ identical in length (3cm) but different in weight‚ tubes of potato in 5 different beakers. Each containing an altered NaCl concentration. The concentrations used in this experiment were‚ 0%‚ 2%‚
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Riley AP Biology Osmosis and Diffusion Lab I. Introduction: Diffusion is vital to many life functions of a cell‚ it allow the transportation of vitally important nutrients and compounds without the expenditure of excess metabolic energy. To explain diffusion‚ it is as if a bottle of perfume is opened at one end of the room‚ then in a short amount of time a person at the other end of the room can detect the scent of the perfume; this is the process of diffusion. Diffusion is a movement from
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Diffusion is one of several transport phenomena that occur in nature. A distinguishing feature of diffusion is that it results in mixing or mass transport without requiring bulk motion. Thus‚ diffusion should not be confused with convection or advection‚ which are other transport mechanisms that use bulk motion to move particles from one place to another. In Latin‚ "diffundere" means "to spread out". There are two ways to introduce the notion of diffusion: either a phenomenological approach starting
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Physioex 9.0 Review Sheet Exercise 1 Cell Transport Mechanisms and Permeability Name Lab Time/Date ___ Activity 1 Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. Size of material and concentration 2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction? The molecules were too large to pass through. This is what I predicted
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