Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999).
Prediction Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999). If you get information from books put the copied text in brackets and at the end put the authors surname and date the book was published in brackets. Then put the full details of the book at the end of the course work in the 'References' In a high concentration of water the amount of solute (e.g. sugar) is low. This could be called a weak or dilute solution. In a low concentration of water the amount of solute (e.g. sugar) is high. This could be called a strong or concentrated solution. When two such solutions are divided by a semi-permeable membrane the water will move from the area of high concentration to the area of low concentration, until both sides are equal (have reached equilibrium). This can be seen in living cells. The cell membrane in cells is semi-permeable and the vacuole contains a sugar/salt solution. So when a cell is placed in distilled water (high water concentration) water will move across the semi-permeable membrane into the cell (lower water concentration) by osmosis, making the cell swell. This cell is now referred to as turgid. If done with potato cells the cells would increase in length volume and mass because of the extra water. If these
Osmosis Investigation
Osmosis Investigation To understand my task, I will first understand the concept of osmosis. Osmosis is the process of water movement from a region of low concentration to a region of high concentration across a semi permeable membrane, which is simply a thin membrane allowing the passage of small molecules. Ex: water molecules. The solutions of high concentration and low concentration are generally referred to as hypertonic and hypotonic solutions respectively. Hypertonic solutions have less water molecules and thus are said to have lower water potential than hypotonic solutions; in hypertonic solutions, solute molecules (ex: sugar, salts) are dissolved and when this occurs, some water molecules form a cluster around them. Thus, there are less free moving water molecules. Therefore, water potential is simply the measure of whether the solution is likely to gain or lose water; it is also the pressure exerted by the freely moving water molecules. It is measured in kilopascals. (kPa) Therefore, osmosis may also be defined as the water movement from a region of high water potential to a region of low water potential across a semi permeable membrane. Osmosis is a very important biological process as it involves the transfer of water in and out of cells. Animal and plant cells both have the presence of the jelly-like substance known as the cytoplasm, made up of about 90
Use scientific knowledge and practical skills to determine the effect of a range of salt solutions (0.2, 0.4, 0.6, 0.8 and 1.0M plus distilled water) on living cells (potato).
Gcse biology osmosis Aims of the investigation: to use scientific knowledge and practical skills to determine the effect of a range of salt solutions (0.2, 0.4, 0.6, 0.8 and 1.0M plus distilled water) on living cells (potato). What factors might affect it? Length - of membrane, Temperature - of water, Concentration - of solution The factor I will change will be. The Independent variable (things you change), the thing that I will be changing in this investigation into the factors affecting osmosis, is the concentrations of the solution that helps me to investigate osmosis with potato tissues. The different sugar concentrations will be changed to see the result of the potatoes when placed in sugar solutions placed in different molarities (strengths). Planning My aim for this experiment is to see the results of potato tissue's mass difference, when placed in different concentrations of sugar solutions. Variables involved: For this experiment I would expect to have 3 different variables, Independent, Dependent, and fixed variables, which all helps me to plan and explain the experiment thoroughly. The Independent variable (things you change), the thing that I will be changing in this investigation into the factors affecting osmosis, is the concentrations of the solution that helps me to investigate osmosis with potato tissues. The different sugar concentrations will be
Osmotic pressure
A study of osmosis Trevor Gotting Sept 30 2007 Ida Bailey Introduction: Osmosis is when water diffuses from an area of high water concentration to a low water concentration. Also there are various effects of solute concentration on cells, which we will be studying. In this lab we will determine how osmosis affects pieces of potatoes. Also we will see how much the change of mass the potato will end up after sitting in the solute. Hypothesis: If the concentration of solutes outside the potato is higher than the concentration of cells in the potato, the potato piece should shrink. Also if both concentration of cells from the potato and the solute are equal, then the potato shouldn't change. Lastly if the concentration of cells in the solute is lower than that in the potato, the potato should get larger. Materials: see page 80. Procedure: see page 80. Change in mass observation Test tube # Solute concentration Initial mass (g) Final mass (g) Change in mass (g) Percent change in mass 0 4.53 g 5.49 g 0.96 g 21.2 % 2 0.2 4.54 g 4.79 g 0.25 g 5.5 % 3 0.4 4.56 g 4.46 g -0.1 g -2.2% 4 0.6 4.53 g 3.67 g -0.87 g -19.2% 5 0.8 4.54 g 3.41 g -1.13 g -24.9% 6 .0 4.55 g 3.41 g -1.08 g -23.7% Calculations: Analyze: . From the graph information it
An Investigation to determine the Water potential of Potato cells.
An Investigation to determine the Water potential of Potato cells Baldeep Bains Hypothesis and background information The cells that are to be used in this investigation will be of a white potato; parenchyma cells. These cells are large, thin-walled and usually have a large vacuole, which holds water, and are filled with sap, 'a solution of ions, sugars and enzymes capable of digesting proteins'. These substances are the solutes that will affect the water potential of the potato cells. Food storage in the form of starch grains is the main function of potato tuber cells. The plasma membrane that bounds a cell is partially permeable; it allows only small molecules such as water, to pass through. Potato cells also have cell walls; these have a rigid lattice structure but are freely permeable. Visit coursework fa in fa fo fa for fa more project fa Do fa not fa redistribute Osmosis is defined as the movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.cofe fer sefefew orfe fek infe fofe fe; Water potential is a measure of the ability of water molecules to move from one region to another. The more water molecules there are per volume of the cell the more likely that by random movement they will collide with the cell's plasma membrane, and travel out of it. Pure water has a ?w of 0. As all
Factors Affecting Osmosis.
FACTORS AFFECTING OSMOSIS AIM The aim of this experiment is to investigate the factors affecting osmosis. I have chosen to investigate the effect varying concentration of sucrose solution has on the amount of osmotic activity between the sucrose solution and a plant cell. The plant cell I have chosen to use is a potato tuber from which I plan to cut potato chips of equal length which I will place in test tubes filled with varying concentrations at equal volumes of sucrose solution. After a set amount of time I will remove the potato chips and record the change in length. BACKGORUND KNOWLEDGE High water potential is a solution which has a high concentration of water and a low concentration of solute (e.g. sugar, sucrose or salt) or no solute at all. Therefore it can either be a very dilute solution of something like sucrose or pure water, however in each case there is a lot of water. Whereas low water potential is the opposite of high water potential being a solution of low concentration of water and high concentration of solute (sugar, sucrose or salt). Hence it can be a concentrated solution of something like sucrose, however in this case there is much less water. When to solutions one of high water potential and one of low water potential are divided by a semi-permeable membrane water molecules will move from the solution of high water potential through the partially
Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.
G.C.S.E Science: Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips Sophie Chapman 25th March 2003 Aim: I shall carry out a sequence of independent experiments in order to investigate how the rate of osmosis in a potato chip is affected when the concentration of sucrose solution is varied. Apparatus: 300ml Sucrose concentration 300ml Distilled Water 2 x 100ml beaker 1 x 100ml Measuring Cylinder 1 x Potatoes 1 x Forceps (Tweezers) 1 x Scalpel Chipper 12 x Polystyrene Cups 1 x Stop - clock Tissues 12 x Sticky Labels 1 x Pen 1 x Calculator 1 x Ruler (measuring mm) 1 x Balance 1 x Polythene Food Bag Cardboard Apparatus Justification: To complete the experiment, I need 300ml distilled water and 300ml sucrose concentration as I intend to carry out 12 tests (using 6 different volumes but each shall be repeated twice) each using a 100ml of liquid whether it be pure water, pure sucrose concentration or a solution containing both. I will detail about the exact volumes of water and sucrose concentration that I want to use in each experiment, in the written procedure. I shall use varied amounts of sucrose solution for each test in order to adjust the concentration - a solution containing more sucrose has a greater concentration than a solution containing less sucrose solution. It is essential that the concentrations be
Investagating the Action of the Enzyme Catalase On the Surface Area of a Potato.
INVESTAGATING HOW INCREASING THE SURFACE AREA OF A POTATO AFEECTS THE AMOUNT OF OXYGEN PRODUCED AIM: My aim in this investigation is to examine how the amount of oxygen produced is affected by increasing the surface area of a potato (increasing the enzyme catalase in the experiment). I will be changing the surface area of a potato and observe how long it takes the oxygen to produce as I increase the surface area of the potato to produce oxygen. The substrate I will be using will be hydrogen peroxide and the biological catalyst will be the potato. VARAIBLES: In this investigation, I will increase the enzyme catalase in the experiment by increasing the surface area of the potato, and observe how it affects the amount of hydrogen peroxide decomposed, producing oxygen at the end of the reaction. The main variables in this investigation that affect the rate at which hydrogen peroxide is broken down are, the concentration of the hydrogen peroxide, the quantity of the hydrogen peroxide solution used, the temperature of the solution, the time at which the experiment is carried out for, the pH value of the catalyst and the surface area of the potato used. If the concentration of the solution is high, more hydrogen peroxide will be decomposed faster producing more oxygen. This is because if the concentration of the reactant is high and the reactants are more concentrated, then
Investigating the cellular water potential of potato cells.
Investigating the cellular water potential of potato cells. Aim: - to determine the water potential of potato cells by using different concentrations of sucrose solution. Introduction:- Water potential is the tendency of water molecules to move from one place to another, water potential can also be represented by the Greek letter psi, ?. The water potential for pure water is 0. This is because there is no tendency of the water molecules to move. The movement of water molecules almost always tends to be from a region of high water potential to a region of lower water potential. This is down the water potential gradient. Water potential can be affected by various factors, such as the amount of solute that is in the solution and the pressure that is being exerted. Solute potential (?s) is the amount by which the solute molecules lower the water potential of a solution. As the solute decreases the water potential of a solution, the water potential becomes more negative as more solute is added. Fig. 1 Diagram of solutions with different water potentials. In the diagram, side A has a less negative and so a higher water potential (it is closer to 0, than side B). This is as side B has a greater amount of solute molecules in it than side A, which means that the water molecules in side A have a greater tendency to move. Side B has the greater solute lower (more negative)
The effect of hydrogen peroxide on catalase if you change the temperature.
The effect of hydrogen peroxide on catalase if you change the temperature AIM Effect of temperature of the action of the Enzyme Catalase. PLANNING Background Knowledge An enzyme is a biological catalyst, it alter the rate of reaction without being changed itself. Enzymes are proteins; they have a very precise three-dimensional shape, which forms a one specific active site on the enzyme. Each enzyme can only convert one kind of substrate molecule in to one kind of product molecule. These are specific. What affects Enzymes? · Temperature- Enzymes stop working if the temperature rises above 40ºC. Increasing the temperature alters the 3D shape and so the enzyme can no longer fit the substrate. · pH- They work best in neutral conditions neither acidic nor alkaline. What affect does catalase have? Catalase is a very fast reacting enzyme, it is found in many living cells, it breaks down hydrogen peroxide to water and oxygen. In fact one molecule of it can deal with six million molecules of hydrogen peroxide in 1 minute. Hydrogen peroxide is toxic so needs to be changed into harmless substances. Catalase Hydrogen peroxide water + oxygen 2H2O2 2H2O + O2 References to practicals referring to enzymes · Biology for You Pg 30 - Experiment 3.1 From looking at this I found out that catalase reacts with hydrogen peroxide to give out water and oxygen. Oxygen bubbles produce
