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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Osmosis is the spontaneous net movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration‚ in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves‚ without input of energy‚ across a semipermeable membrane separating two solutions of different concentrations. Although osmosis does not require input of energy‚ it does use kinetic energy and
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LAB EXERCISE: Diffusion and Osmosis Laboratory Objectives After completing this lab topic‚ you should be able to: 1. Describe the mechanism of diffusion at the molecular level. 2. List several factors that influence the rate of diffusion. 3. Explain why diffusion is important to cells. 4. Describe a selectively permeable membrane‚ and explain its role in osmosis. 5. Define hypotonic‚ hypertonic‚ and isotonic in terms of relative concentrations of osmotically active substances. 6. Discuss
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The Cell membrane surrounds all living cells and is the most important organelle‚ there is also a similar plasma membrane that surrounds all the organelles except for the ribosome. The membrane controls how and what substances can move in and out of the cell/organelle The structure of the membrane is often referred to as the “Fluid Mosaic Model”; this is because of the way it is structured It is composed of phospholipids‚ proteins‚ and carbohydrates‚ which are arranged in a fluid
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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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Sheet Results 1. Explain why increasing extracellular K+ reduces the net diffusion of K+ out of the neuron through the K+ leak channels. Your answer: Because outside a typical cell‚ the concentration of K+ is about 5mM and the concentration of Na+ is about 150 mM. When you increase the concentration of K+ from 5 to 25 mM and reduce concentration of Na+ from 150 to 130 mM‚ the outside has more concentration of K+. The membrane is permeable to a particular ion‚ that ion will diffuse down its concentration
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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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Osmosis Aim: To determine the concentration of cell sap in a potato cell. Osmosis is the movement of water through a semi-permeable membrane. It starts from a weak solution and becomes a more stronger solution until the concentrations on both sides are equal. To investigate the range of solutions needed to find the point at which the surrounding solution is the same as the cell sap in the vacuole.
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Part 1 Part 1 of the experiment investigated the effect of different temperatures on beetroot cell membranes (a type of plant cell). Through this experiment‚ the process of diffusion and osmosis was in action. Various temperatures ranging from low temperatures to high temperatures such as -5⁰C‚ 5⁰C‚ 30⁰C‚ 50⁰C and 80⁰C were used to investigate the temperature effects on beetroot cell membranes. The hypothesis predicted that the higher the temperature the darker the beetroot substance and the lower
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Transport of Solute in Solvent through Osmosis or Diffusion Due to Different Concentration Gradients Passing Through a Semi-permeable Membrane between Cell and Cells Environment Bio 101 Objective: The objective is to simulate passive transport: diffusion of solutes and osmosis of water through a semipermeable membrane (dialysis tubing). The experiment will show how molecules in solution move from areas of higher concentration to areas of lower concentration in the attempt to reach homeostasis
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