Osmosis and Water Potential Year 11 Emary Venter INTRODUCTION: The cell is the basic unit of living things‚ and is made up of multiple organelles. Organelles are membrane bound subdivisions‚ each specialised for a specific function. This experiment looks at the Plasma Membrane‚ which is a semipermeable layer surrounding the cell. It’s primary job is to control what goes in and out of the cell. Molecules can move across this membrane in either an active movement or a passive movement
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a deflated balloon. It also maintains its flexibility over a range of temperatures for example it prevents solidification at low temperatures. Cholesterol can approximately make up 50% of the plasma membrane. It Reduces membrane fluidity by reducing phospholipid movement therefor giving the membrane the shape it needs instead of it looking like a deflated balloon. It also maintains its flexibility over a range of temperatures for
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"Explain the concept of homeostasis with reference to the control of heart rate‚ breathing rate‚ body temperature and blood glucose levels" P5 Homeostasis is where the body keeps a constant internal environment. This involves all the metabolic processes taking place In the body as well as the blood‚ tissue fluid and all the contents in the body ’s cells. There are a range of variables from heart rate to the blood glucose levels that the body will take into account. Negative feedback will occur
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ABSTRACT The effect of molecular weight on the rate of diffusion was measured using two tests namely: the glass tube test and the agar-water test. The set-up of the glass tube test used two cotton balls of the same size. One cotton ball is moistened with hydrochloric acid (HCl) and the other one is moistened with ammonium hydroxide (NH4OH). The two cotton balls were inserted in both ends of the glass tube. NH4OH which has a lighter molecular weight (35.0459 g/mole) diffused with a faster rate (dave=20
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different concentrations of glucose affect osmosis in potato cells. Osmosis is the passive process of diffusing water which means within this experiment particles of water will move from a lower concentrated area to an area of higher concentration ; in this case it will be a concentration of glucose. Diffusion is when particles move from an area of high concentration to low concentration ; for example when a smell of cooking spreads through the house. Osmosis is a vital mechanism in the transport of
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and air as the control. When performing this experiment‚ the main element to consider is hypertonic‚ hypotonic and isotonic solutions and how they relate to osmosis. Osmosis is the process where a fluid passes through a semipermeable membrane‚ which moves from an area which the solute is present in high concentrations. As a result of osmosis‚ there will be an equal amount of fluid on either side of the barrier‚ creating an isotonic solution. When cells are placed in an isotonic solution‚ the movement
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GCSE Biology: Osmosis in a Potato Aim To investigate the effect of placing a piece of potato in a given strength of sugar solution. Prediction I predict that‚ as the solution becomes more concentrated the more the cell will shrink‚ as the water‚ of higher concentration inside the potato cells‚ flows down a concentration gradient into the solution‚ which has a lower concentration of water molecules. If we say that the percentage change when the potato is placed in the 1M solution is x%. I predict
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Osmosis and Diffusion Lab Observations: Diffusion: | Before | After | Color of liquid sack | clear | blue | Color of liquid in beaker | dirty yellow | golden | Glucose present Stick Test | no | yes | Color of the test stick | No change in color | Green | Osmosis: | Fresh | Salt | Beginning mass of potato | 2.51 | 2.16 | Texture of potato | Dry | Dry | Overnight mass | 3.12 | 1.84 | Overnight Texture | Hard‚ strong | Squishy‚ pliable | Data and Analysis: Diffusion:
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of this molecular movement. Diffusion is the random movement of molecules from an area of higher concentration to areas of lower concentration. Osmosis is a special kind of diffusion where water moves through a selectively permeable membrane that only allows certain molecules to diffuse though (Lab Manual 7e‚ 2010). Diffusion or osmosis occurs until dynamic equilibrium has been reached. This is the point where the concentrations in both areas are equal and no net movement will occur
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Observing Osmosis in Potato Cells Planning Purpose: To observe the effect of osmosis on plant cells. Hypothesis: The higher the salt content of the water‚ the lower the mass of the potato. Variables: Independent: the salt percentage of the solution Dependent: the weight of the potato in grams Controlled: the amount of water the length of time between measurements the method of measuring the type of plant cells tested Equipment: (as seen on 2A Human Biology task sheet)
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