To determine the water potential of a potato tuber cell using varying salt solution.
Aim To determine the water potential of a potato tuber cell using varying salt solution. Introduction Osmosis is the diffusion of water molecules from a region where it has higher water potential to a region where it has lower water potential through a partially permeable membrane1. As osmosis is a type of diffusion the same things that affect diffusion have an effect on osmosis some of theses things are: * The concentration gradient - the more the difference in molecules on one side of the membrane compared to the other, the greater the number of molecules passing through the membrane and therefore the faster the rate of diffusion2. * The surface area - the larger the area the quicker the rate of diffusion * The size of the diffusing particles - the smaller the particle the quicker the rate and polar molecules diffuse faster than non-polar ones3. * The temperature - the higher the temperature the more kinetic energy the particles have and so the faster they move. From the diagram4 we can see the process of osmosis in a simple expression. On the right side there is pure water, which has the maximum water potential of 0. Water potential is the pressure created by water. As you can see from the diagram the pure water is pushing its way through the semi permeable membrane at a high pressure. This is its water potential. Water potential is measured in kilopascals (kPa)
How the structure of cells is related to their function.
How the structure of cells is related to their function. All living things are made up of cells, whether its plants, humans or even bacteria. There are two different types of cells one is the prokaryotic and the other is the eukaryotic. The name cell was used by an English man who in 1665 use the first microscope and reported seeing what he described looked like the sleeping chambers in the monasteries that were called cells, in a piece of cork.1 The first of the two types is the Prokaryotic cell, the pro meaning before the nucleus as this cell has no true nucleus.2 Prokaryotic cells are surrounded by a cell wall and a cells membrane, and in some ways this makes them similar to a plant cell which is eukaryotic, but they have no nucleus or organelles inside, but they do have flagella's and cilia on the outside. The flagellum is a long whip like tail attached to the end of the prokaryotic cell which helps with its movement. The cilia are small spiked hairs that help to transport fluid in and out of the cell and for protection against harmful substances. They are also found in abundance in the eukaryotic cells in the human trachea where they collect dirt, they either by moving it down into the stomach or push it back up into to the mouth to spit it out.3 One of the most common prokaryotic cells would be bacteria, they are the smallest cellular organism, and each human being
Effects of Surface Area on Catalase Activity in Potato.
Effects of Surface Area on Catalase Activity in Potato Aim To investigate the effect of surface area on the activity of Catalase in potato. Hypothesis I predict that the potato which has been cut into more pieces will have the largest surface area. A larger surface area means that there will be more catalase molecules coming in contact with the reacting substrate, hydrogen peroxide. Enzymes react when particles come into contact with their active sites; if more of the enzyme is exposed (larger surface area) a greater number of active sites will be available to react with the hydrogen peroxide. The surface area of a 5cm tube with a diameter of 2cm equals 37.0 cms² ( 2 rh+2 r² ), but a 5 cm tube cut into five 1cm segments has a surface area of 62.83 cms². Every time another segment is cut from the 5cm tube two more areas have to taken into account, this means each time the 5cm tube is cut into a piece the surface area will increase. As a larger surface area produces a higher rate of reaction, my results should show a higher volume of gas released when using a potato with a larger surface area. Background Knowledge Enzymes are proteins which can be referred to as biological catalysts. Catalysts are molecules which increase the rate of chemical reactions and remain unchanged at the end of the reaction. Enzymes are made up of a chain of amino acids which are
Investigation into the effects of osmosis on Potato cells
Investigation into the effects of osmosis on Potato cells PLANNING AIM The aim of this investigation is to find out the concentration of cell sap in potato tissue. Variables * Controlled-Starting length will be as close to 3.00cm possible, starting volume, which is 20ml also the same time the potato cells are kept in solution and same conditions for each cylinder. * Dependant-Length of potato cylinder (before and after osmosis has occurred). * Independent-Concentrations of solutions which are: (m) 0,0.1,0.2,0.3,0.4,0.5 Solutions Vol. Of glucose * 0.5 = M (0.5 = starting glucose concentration) Total volume ) 0 * 0.5 = 0 M 20 2) 4 *0.5 =0.1M 20 3) 8 *0.5 =0.2M 20 4) 12 *0.5 =0.3M 20 5) 16 *0.5 =0.4M 6) 20 *0.5 =0.5M 20 20 Prediction I predict that this experiment will have different results throughout all the concentrations. Osmosis depends on two concentrations; outside (glucose solution) and inside (cell sap). I feel that my experiment will prove that osmosis has occurred meaning the water has moved form a high concentration to a low concentration. But. If the cell was already turgid when we measured it, the movement of water from a higher concentration to a lower concentration means we will find the potato cell will shrink as the
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
GCSE Bioligy Case Sudy - MRSA
Is going to hospital too much of a risk due to the outbreak of MRSA? Contents Page * Introduction 1 * What is MRSA? 2 * How does MRSA reproduce? 2 * Why is MRSA resistatant to most antibiotics? 3 * How do antibiotics work? 3 * How can MRSA be prevented? 3 * How does MRSA harm someone? 4 * What are the symptoms of MRSA? 4 * MRSA in hospitals 5 * Arguments against going to hospital 5 * Arguments In favour of going to hospital 5 * Evaluation of the evidence 6 * Conclusion 6 * Alternative Conclusion 6 * Bibliography 7 Introduction In this
Isotonic Point of Potatoes
Aim: To determine the isotonic point of a potato. Research Question: To determine the isotonic point of a potato by placing it in different concentrations of salt (NaCl) solution and measuring the change in mass after a fixed time period. Background Information Osmosis is defined as the movement of water molecules from a region of low solute concentration, to a region of high solute concentration, through a semi permeable membrane, which is one that allows only certain small particles to pass through. A solution with a high water concentration, or low solute concentration is also called a hypotonic solution, and one with a low water concentration is known as a hypertonic solution. When a cell is placed inside a hypertonic solution, water molecules diffuse out of the cell (which has a higher water concentration, or is hypotonic) through the cell membrane, due to the high solute concentration outside the cell. This process is called exosmosis, and it makes the cell flaccid, as it loses water. The very theory can be applied to plants, which causes wilting. When a cell is placed in a hypotonic solution, water molecules diffuse from the solution into the cell, as the solvent concentration of the cell is lower. This causes the cell to become turgid, and it is called endosmosis. Source - http://biosimplicity.webs.com/ A solution which has the same concentration as that of
Osmosis in Potato Chips
Year 11 GCSE Biology Coursework - Osmosis in Potato Chips Aim This experiment is to find out how osmosis in potato chips is affected by the concentration of sucrose solution present in the solution around it and also the ways in which osmosis occurs i.e. where the water molecules involved are travelling. Prediction I think that the higher the concentration of sucrose in the solution around the potato chip, the more weight the chip will lose as the experiment is run. I also think that in a concentration of sucrose where there is a lot more water than there is sucrose that the chip will gain weight as the experiment goes on. I think this because in a solution where there is a low water concentration, where a potato chip with a higher water concentration is placed, osmosis dictates that water will pass out of the potato chip (down the concentration gradient), out through the cell's semi-permeable membrane and into the solution. This is how osmosis works. Osmosis is: The movement of water molecules from a high concentration of water, through a semi-permeable membrane into a low concentration of water. In this case, there would have to be a higher concentration of sucrose in the solution to give the solution a low water concentration. This would mean that the potato chip would have a higher concentration of water. The movement of water molecules from the chip into the
Potato / Osmosis Experiment.
POTATO OSMOSIS EXPERIMENT Introduction Osmosis is the diffusion of water molecules across a partially permeable membrane with the concentration gradient. This means that water molecules move from where they are in a higher concentration, to an area where they are in a lower concentration. Therefore, osmosis is always trying to make a concentrated solution more dilute. Why a partially permeable membrane is needed Molecules will always spread out as evenly as they are able to. The partially permeable membrane allows the water molecules to spread out, and thus making the concentrated sugar solution more dilute; but the non-partially permeable membrane keeps the water molecules in a compact space and prevents osmosis from occurring. AIM: The aim of the experiment is to calculate the concentration of sucrose solution that is isotonic to the cytoplasm within the plant cells of potato samples. Theory- Reasons for Prediction: I predict that the concentration of the sucrose solution will have an affect on the amount of osmosis taking place. I predict that by increasing the concentration of the sucrose solution the amount of osmosis will increase. When osmosis occurs, the previously more concentrated sugar solution gains mass (since there is a net gain of water molecules there) and the previously more dilute solution loses mass (since water molecules are leaving it to dilute
Data Analysis - Osmosis in Potatoes
G.C.S.E. Biology Data Analysis - Osmosis in Potato Chips Contents Page . Aim.............................................................................................................. 3 2. Results........................................................................................................ 3 2.1 Tables 2.2 Graphs 3. Analysis....................................................................................................... 5 4. Evaluation................................................................................................... 6 5. Conclusion.................................................................................................. 7 6. Bibliography................................................................................................ 8 . AIM The purpose of this experiment was to analyse the effect of osmosis in potato chips (cut slices) and then be able to explain the significance of this in the human body. I predicted that as the concentration of the solute was increased, the mass of the potato would decrease because of osmosis. 2. RESULTS 2.1 Tables Potato No. Concentration (M) Start mass (g) Finish mass (g) Change in mass (g) % change in mass Average % change in mass A1 0.0 .79 2.01 0.22 2.29 9.68 A2 0.0 .79 .94 0.15 8.38 A3 0.0 .79 .94 0.15 8.38 B1 0.5 .79 .86 0.07 3.91 5.40 B2 0.5
