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)
The effect of sucrose solution concentration On osmosis in potato chips
The effect of sucrose solution concentration On osmosis in potato chips Plan I am going to cut six pieces of potato using a borer. They will all the same weight. I will make them all 0.7g. I will be able to make sure they are all the same weight-using scales. If a piece of potato is too big I will use a scalpel and a tile to trim it so they are all the same weight and then place these into a test tube each. I will hold the test tubes in a test tube rack. Using the measuring cylinder I will measure 10ml of each strength of sugar solution rinsing the measuring cylinder after each measure. This will then be added into separate test tubes with the pieces of potato. E.g. a piece of potato will have 0.0M strength; a piece of potato will have 0.2M strength and a piece of potato will have 0.4M strength etc. I will put a sticky label on each test tube stating what strength of sugar solution it contains. I will then leave these for 2 hours and see what happens then record my results. APPARATUS A potato Sugar solutions (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) Borer Scalpel Tweezers Scales 6 test tubes Test tube rack Measuring cylinder I will measure the amount of sugar solution in the test tubes. I will change the strength of sugar solution in each test tube. To make the experiment a fair test I will keep the weight of the pieces the same weight I will also only add the same
Effect of enzyme concentration on initial rate of reaction
Effect of enzyme concentration on initial rate of reaction The objective of this experiment is to determine how differentiating the concentration of the enzyme catalase affects the initial rate of reaction, in the decomposition of Hydrogen Peroxide (H2O2) The equation of this reaction is: Hydrogen Peroxide(aq) --> Water(l) + Oxygen(g) 2H2O2(aq) + catalase(aq) --> 2H2O(l) + O2(g) The source of the enzyme Catalase in this experiment will be yeast, specifically the Saccharomyces Cerewisea strain, as it is easy to obtain and very safe with no harmful effects to the environment. The technique used to obtain a set of results will be the downward displacement method, where evolved oxygen product from the reaction is passed through a delivery tube and into a water filled burette, pushing the water out of the burette, leaving obtainable results of Oxygen collected. These results will be taken every 5 seconds for two minutes and will give the rate of reaction. My Equipment will be: * Burette * Side-arm Conical Flask * Bung * Tubing * Yeast * Hydrogen peroxide * Water Bath * Water/Margarine Tub * Distilled water/pH7 buffer * Stopwatch I chose to have a burette to collect the evolved Oxygen, as it has a great degree of accuracy. The gas can be measured to 0.05ml or 0.5cm3. I chose to have a side arm conical flask to provide a source for the evolved oxygen to travel
effects of substrate concentration on the activity of the enzyme catalase.
Investigate the effects of substrate concentration on the activity of the enzyme catalase. To explain this, catalase is an enzyme found in potato cells, catalase breaks down the substrate Hydrogen-Peroxide into water + oxygen. Hydrogen Peroxide itself is a waste product found in potatoes and other fruit + vegetables. When I do this I will see with different concentrations of the substrate and see how quick the enzyme catalase works on it. The four things that affect the rate at which the substrate and enzyme would react are as follow:- * Susceptibility of temperature change. * Susceptibility to PH changes. * Enzyme concentration. * Substrate concentration. Now I will explain each one of these in detail and how they can change the rate of reaction in many different ways. Susceptibility of temperature: - Chemical reactions can be speeded up by heating the reactants, this makes molecules speed up and have sufficient energy for more successful collisions. If the temperature is too high the enzyme would vibrate and it would denature because the active-site would change shape. Susceptibility of PH changes: - Enzymes can be denatured by changes in PH. This happens because the ionisation of the Amino acids changes, the Ionic bonds with stabilise the enzyme, that shape is broken so they are no longer stable. So you need the right PH for the ionic bonds to stay stable for the
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
In this essay, I will be stating the factors affected by enzymes, the purpose of enzymes, and finally, the uses of enzymes.
In this essay, I will be stating the factors affected by enzymes, the purpose of enzymes, and finally, the uses of enzymes. What are Enzymes? Enzymes are biological catalysts. They have enormous catalytic power. Catalysts are substances that speed up reactions without being used up. Enzymes help the reactions that occur in our bodies by controlling the rate of reaction. Enzymes are also important in respiration. Aerobic respiration releases energy from glucose. Most enzymes are made of proteins. They are made up of long chains of amino acids and also has a unique shape, as shown in the picture opposite. The purpose of this is to allow another molecule to fit with the enzyme. These molecules are known to be called substrates. These are designed to fit into the enzymes to create a 'lock-and-key' mechanism which will then create the product molecule. Here is a picture to show how this would look like. As humans, enzymes also have an optimum temperature. The optimum temperature of enzymes will vary depending on which part of the body the enzyme is present. In most cases, the optimum temperature of enzymes is 40°. If the temperature exceeds 40°, the enzyme will denature, as of humans, if they exceed 40°, they would die. If the enzyme denatures, it basically means the breaking down of the active site, so the substrate cannot fit into it any more. Enzymes don't just have
Digestion. The digestive system is made up of a complex series of organs and glands that together process the food that enters the body.
The Ways of Digestion The digestive system is made up of a complex series of organs and glands that together process the food that enters the body. In order to use the food that is eaten, it has to be broken down into smaller molecules it can process; it also has to excrete the waste. The digestive process begins in the mouth, where the food is broken down by mastication. Mastication and saliva secretion work together: chewing increases the surface area of foods, which helps to accelerate the breakdown of starch molecules. Mastication causes exocrine glands under the tongue to produce saliva. The starch is broken down into glucose by a production of salivary amylase, an enzyme from the salivary glands. It moistens and compacts the food that has been chewed so that your tongue can roll it into a ball, called the bolus, and push it to the back of your mouth so that you can swallow and have an easy passage down through the pharynx and esophagus. The esophagus is a muscular tube whose muscular contractions propel food to the stomach. The food reaches the pharynx when the bolus has been produced. The bolus triggers an involuntary swallowing reflex that prevents food from entering the lungs, and directs the bolus into the esophagus. When the food has been chewed and swallowed, it enters the esophagus. The esophagus is a long tube that leads food from the mouth to the stomach. The
Investigating Osmosis: The Molarity Of A Potato Cell.
Investigating Osmosis: The Molarity Of A Potato Cell Introduction Knowing that osmosis (diffusion of water) will occur across a semi-permeable membrane whenever there is a difference between the water concentrations on the two sides of the membrane, and knowing that when this happens to cells, they will either become turgid if water flows into them, or plasmolysed if water flows out of them, therefore changing their volume. I want to test the hypothesis that: If the concentration of a solution into which a cylinder of potato is placed is greater than a certain level the cylinder will decrease in mass, and if the concentration is less than that level it will increase in mass. Prediction I believe from my past knowledge of a similar experiment involving raw eggs that the potato cylinders placed in the distilled water will be hypertonic, therefore the water will diffuse by osmosis into the potato from an area of high concentration down the concentration gradient. This will result in a gain of mass for the potato. However in the 1.0M solution I think that the opposite will occur as there will be a higher concentration of water within the potato than the solution, this will make the potato hypotonic and it will lose its water content as the water diffuses out. A difference between the egg experiment and the potato experiment is that the potato cells will not reach a
An Investigation to find the Water Potential of Plant Tissue
An Investigation to find the Water Potential of Plant Tissue Benjamin Doughty Aim: To find the water potential of plant tissue by investigating the effects of varying concentrations of sugar solutions on the amount of osmotic activity between the solution and potato cylinders. Hypothesis: Osmosis is defined as the net movement of water from regions of high water potential to regions of low water potential. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other. Prediction: Pure Water has the highest water potential (zero). For this particular investigation I think that the lower the concentration of the sugar solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from an area of high sugar concentration, i.e. in the water itself, to an area of low concentration, i.e. in the potato chip. Therefore, the chips in higher water concentrations will have a larger mass than in higher sugar concentrations. Plant cells always have a
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
