water-soluble substances cross the membrane through simple diffusion‚ facilitated diffusion and active transport. Osmosis is thought of as the diffusion of water from an area of high concentration of water molecules to an area of low concentration‚ across a partially permeable membrane. To define osmosis more accurately we define it in terms of water potential. Water potential is a measure of how easy it is for water molecules to move. Diffusion occurs because substances attract a ‘cloud’ of polar water
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Investigating the Relationship between Cell Size and Rate of Diffusion Ban Madi 11 Dp Biology SL Research Question: How does the size of the cell affect its efficiency in exchanging substances through several ways‚ like diffusion? Aim: To plan and carry out an investigation to show the relationship between volume/Cm3‚ surface area‚ and diffusion using agar cubes measured in time/s; and to demonstrate‚ using diffusion‚ why the size of cells is limited‚ keeping the room temperature
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Diffusion in agar cubes Introduction: All cells are dependent on a processes called diffusion‚ which is the movement of a substance from an area of higher concentration to an area of lower concentration. Cells need to obtain certain essential substances‚ like oxygen‚ for their survival. The rate of diffusion is said to be dependent upon the various factors: Size of molecules that have to diffuse‚ concentration gradient‚ the distance across which diffusion occurs‚ number of pores/openings‚ surface
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Physioex 9.0 Review Sheet Exercise 1 Cell Transport Mechanisms and Permeability Name __Christopher Scott_ Lab Time/Date ___1/15/2014 Activity 1 Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. ___ Two variables that affect rate of diffusion are molecule size and plasma membrane composition. A larger molecule will diffuse more slowly than a smaller molecule. The lipid content of the plasma membrane determines permeability of certain molecules. A
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conditions‚ the pyruvate is converted into lactic acid. Diffusion After viewing the animation‚ answer these questions. 1. Molecules dissolved in a solution are in constant random motion due to their kinectic energy. 2. One result of this motion is dissolved molecules become evenly distributed throughout the solution . 3. This tendency of molecules to spread out is an example of diffusion . 4. Even as a solid lump‚ the individual sugar
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ACTIVITY ONE- Cell Transport Mechanisms and Permeability: Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. Molecular weight affects the rate of diffusion because the bigger the size of the molecule the longer it will take to diffuse. Membrane size is another variable that affects the rate of diffusion because if the membrane’s pores are small it will take molecules longer to diffuse though it than if the pores were larger. Also‚ membrane thickness
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will become hypotonic and swell up as the time increased. “Diffusion is a passive process in which the random mixing of particles in a solution occurs because of the particle ’s kinetic energy “(Allen C. 2006)‚ and is subjected to detect the presence of each of the substances given in the biochemical testing‚ the increase in temperature‚ and different reagent used are some aspect that could cause the difference of diffusion in certain solution. It was clear that the protocols Glucose‚ Albumin
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differences in the interior and exterior of the cell. The second type is active processes which use energy known as ATP to power the transport. There are two main types of passive processes called diffusion and filtration. This can be split into different types such as simple diffisuion‚ facilitated diffusion‚ osmosis and filtration. The objective of these experiments is to provide information on the passage of solutes and water through semi permeable membranes and relate them back to the study
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BIOLOGY – TRANSPORT ACROSS MEMBRANE define diffusion and describe its role in nutrient uptake and gaseous exchange in plants and humans define osmosis and describe the effects of osmosis on plant and animal tissues define active transport and discuss its importance as an energy-consuming process by which substances are transported against a concentration gradient‚ as in ion uptake by root hairs and uptake of glucose by cells in the villi . A cell is surrounded by a layer of cell surface membrane
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out of cells Diffusion: (mixing molecules) Molecules and ions in a liquid or a gas move continuously. The movement is quite random‚ and the particles change direction as they bump into one another. The particles collide more often when they are close together (when they are concentrated) and so they tend to diffuse‚ or spread out‚ until they are spaced evenly throughout the gas or liquid. The random movement of particles is due to their own kinetic energy. When the diffusion happens in living
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