#### Statistical Technique.

Statistical Technique The Mann-Whitney U Test will be used as differences between two treatments (two carbohydrates, sucrose and glucose) are being investigated and measurements have been taken at least six times with each treatment. Random sampling will therefore be useful and the data summarised using the median. Results Table: This table shows the volume of gas collected in five minutes in cm from each carbohydrate . Starch Sucrose Lactose Glucose 0 4 0 4 0 3 0 6 0 3 0 6 0 3 0 4 0 2 0 5 0 3 0 4 As neither starch nor lactose produced any result they shall not be investigated in the statistical test. Null Hypothesis: there is no difference between the volume of gas produced by sucrose or by glucose. Data set A: Rankings 7.5 3.5 3.5 3.5 3.5 Data set A: Observations 4 3 3 3 2 3 Data set B: Rankings 7.5 1.5 1.5 7.5 0 7.5 Data set B: Observations 4 6 6 4 5 4 Ra = 22.5 Na = 6 Nb = 6 Rb = 55.5 Ra + Rb = [(Na + Nb)(Na + Nb + 1)] = Ra + Rb = 78 2 Ua = NaNb + Nb(Nb + 1) - Rb = Ua = 36 + 21 - 55.5 = 1.5 2 Ub = NbNa + Na(Na + 1) - Ra = Ub = 36 + 21 - 22.5 = 34.5 2 Na = 6 Nb = 6 CV = 5 U CV 1.5 < 5 As the smallest U value is less than the critical value the null hypothesis can be rejected. Therefore it has been statistically

• Word count: 1792
• Level: AS and A Level
• Subject: Science

#### permeability of beetroot membranes

An investigation into how the concentration of a solution affects the rate of osmosis in a potato Definitions of important terms: Osmosis: Osmosis is the movement of water through a partially permeable membrane from a low concentration into a high concentration. This continues until both solutions are of equal concentration. Osmosis is a natural occurrence that can be simulated with an artificial membrane such as a visking tube. The rate of osmosis can be determined by the difference in water potential between the two substances on either side of the partially permeable membrane. Water potential (symbol??): Water molecules possess kinetic energy, which means that they are continually moving around when in a gas or liquid state. The higher the concentration of water molecules in a system, the greater the total kinetic energy of water molecules in that system and also the higher its water potential. Water potential is a measure of the energy available in an aqueous solution to cause the migration of water molecules across a semi-permeable cell membrane during osmosis. Water moves from areas of high (less negative) to areas of low (more negative) potential. Pure water is given the value zero. Aim of My Experiment: I am going to study whether or not the amount of water that may be taken into a potato cell by osmosis is affected by the concentration of a solution on one

• Word count: 3162
• Level: AS and A Level
• Subject: Science

#### Establish the cytoplasm concentration of carrot cells.

Biology Carrot Experiment Aim: To establish the cytoplasm concentration of carrot cells. Method * Use a pipette to measure the different volumes of sucrose and distilled water into six test tubes (use different pipettes for water and sucrose solutions to avoid contamination). In the following ratios in order to get the correct concentrations correct. Sucrose Concn Volume of sucrose cm3 Volume of water cm3 0 0 20 0.2 4 6 0.4 8 2 0.6 2 8 0.8 6 4 20 0 * Use a scalpel to cut 18 even-sized pieces of carrot approximately 10x5x5 millimetres in size. * Weigh three pieces of carrot then place them into one of the test tubes containing the sucrose solution and cover with Clingfilm. * Repeat this process for the six test tubes containing the sucrose solution * Leave for as long as possible at least 48 hours. Results Sucrose Conc. Volume of sucrose cm3 Volume of water cm3 Initial Mass of carrot (g) Final Mass of carrot (g) Change in mass % 0 0 20 3.51 4.03 4.81% 0.2 4 6 3.38 3.45 2.07% 0.4 8 2 3.3 3.33 0.91% 0.6 2 8 3.22 3 -6.83% 0.8 6 4 3.54 3.05 -13.84% 20 0 3.55 2.73 -23.10% Graph Conclusion My results show that in the sucrose concentrations 0-0.38 water entered the carrot cells from the surrounding sucrose solution. During this period the carrot cell cytoplasm has a lower water potential than the surrounding

• Word count: 595
• Level: AS and A Level
• Subject: Science

#### Making a 1% solution of glucose.

Making a 1% solution of glucose. Introduction. A standard solution can be an important solution and a useful solution to use, as it is a known solution, the value is also known and that means that the solutions can be tested and be compared against unknown sources to test with and to identify its value. A standard solution will be used in a situation when the scientists have an unknown solution where they will test it to find out what it will be, Aim of activity. Our aim is to make up a standard 1% solution of glucose in water using 1g glucose and 100ml water and use this as a control solution. Materials and method. Materials. 00ml conical glass Balancing scale Measuring boat Squeezy bottle Stirring rod Bunsen burner Spatula Method. Method for making the solution. . Put the measuring boat onto the scale and reset the number to zero. 2. Put the 1g of glucose on the measuring boat using a spatula. 3. Put the glucose into the flask. 4. Rinse the excess glucose off the boat and the flask. 5. Pour water into the flask; fill it up to 100ml from the tap. 6. Fill the rest of the flask by using the Squeezy bottle until you get exactly to 100ml. Method for testing the solution. . Place a small amount of the 1% solution and add a few drops of benedict's solution, place the test tube in a beaker of heated water to help the reaction. 2. Collect the solution A+B

• Word count: 598
• Level: AS and A Level
• Subject: Science

#### Why is water a good transport medium?

BIOLOGY ESSAY Water makes a very efficient transport medium within plants and living things. Water is a polar molecule, this means when hydrogen forms a covalent bond with oxygen the electrons are attracted more to the heavier oxygen molecule, giving it a partial negative charge, leaving the hydrogen with a partial positive, making the molecule to be polarized. Water particles are attracted to each other by hydrogen bonds. When two water molecules get close together, the polar forces draw the molecules together. The oxygen atom of one water molecule will bond with several hydrogen atoms of other water molecules. These bonds are called hydrogen bonds and means water molecules stick together making them cohesive. This is good in organisms because it means when water is transported though the body molecules will stick together. Water molecules are also adhesive, meaning they are attracted to other polar molecules and solid surfaces. Due to the interaction of the forces of adhesion and cohesion, water exhibits capillary action. Water rises into a narrow tube against the force of gravity. Water sticks to the inside wall of the tube and surface tension then straightens the surface causing a surface rise and more water is pulled up through cohesion. The process continues as the water flows up the tube until there is enough water so the gravity balances the adhesive force meaning

• Word count: 518
• Level: AS and A Level
• Subject: Science

#### In this experiment we will be testing fluids for glucose because a body fluid sample is detected at a scene of a crime and a sample taken using a cotton bud. The prime suspect is a diabetic so that is the reason why we are testing for glucose.

Glucose Coursework Introduction: In this experiment we will be testing fluids for glucose because a body fluid sample is detected at a scene of a crime and a sample taken using a cotton bud. The prime suspect is a diabetic so that is the reason why we are testing for glucose. Planning: The person who is the suspect is a diabetic. So a test using Benedict's solution will be used for reducing glucose. There will be two tests. One of the tests will be using glucose mixed with glucose and the other test will be with a sample of body solution mixed with glucose. The sample of body solution will replace the Benedict's solution. Safety Points: There are not really any safety points in this experiment because none of the materials used in this experiment were dangerous. You just had to make sure that you didn't burn yourself when the Bunsen burner was on and let the test tubes and the tripod cool down before touching them and taking them out of the beaker. Materials and Methods: The materials that we used in this experiment were: * Bunsen Burner * Test Tube * Test Tube Rack * Tripod * Gauze mat * Benedict's solution * Glucose * Beaker * Pipette * Bench mat * Measuring Scale This experiment took quite along time. Here is the method: . First of all we got all of the equipment set out. 2. Then we measured out 1 gram of glucose on a measuring scale. 3. Then we

• Word count: 852
• Level: AS and A Level
• Subject: Science

#### The Biological Significance Of Sugars.

The Biological Significance Of Sugars Sugars are very important in our day-to-day lives; they have many significant functions such as giving out energy, providing utilisation or transport, providing protection and other such structural roles. They, along with starch and cellulose, are found in carbohydrates, which contain only 3 elements: carbon, hydrogen and oxygen of which there is always twice as much hydrogen as oxygen. Sugars are classified according to the number of carbon atoms present. For example, 3 carbons equal a triose, 5 carbons equal a pentose and 6 carbons equal a hexose etc. Carbohydrates are divided into two major groups, the sugars (monosaccharides and disaccharides) and the non-sugars (polysaccharides). Monosaccharides are a single sugar, which is made up of small molecules with low masses. These are always sweet tasting, soluble in water and form crystals when in solid form. Examples of monosaccharide sugars include alpha & beta glucose, ribose, fructose, glyceraldehydes and deoxyribose etc. The general formula for them is: (CH²O)n where n is the number of carbon atoms present. The ratio is always 1:2:1. Most monosaccharides are the producers of energy, however some are used for structural purposes, for example ribose and deoxyribose, both pentose sugars, are used to make RNA and DNA. Alpha and beta glucose and fructose are hexose sugars, which

• Word count: 683
• Level: AS and A Level
• Subject: Science

#### Alleopathy

Will the allelochemicals produced by grass seeds inhibit the growth of wheat seeds? Abstract: This investigation was designed to see what effect the allelopathic chemicals of grass seeds had on wheat seeds. This was done by placing 20 grass seeds on a petri dish, with two sheets of filter paper inside, which was watered with 5ml of distilled water every three days for a week. After one week of growth the seeds were removed, then another 20 wheat seeds were placed on the second piece of filter paper as the first was discarded, and the same process was repeated. This was repeated in five more petri dishes. At the same time 60 wheat seeds were grown as a control, so the results could be compared. A clear inhibition of root and shoot growth could be seen in the experimental group compared to the control group. Many wheat seeds in the test group did not even germinate. In conclusion the allelochemicals produced by grass seeds have an inhibitory effect on the wheat seeds. Aim: The aim of this investigation is to see whether the allelochemicals produced by grass at germination inhibit the growth of wheat seeds. Background: What is allelopathy? Allelopathy is any direct or indirect harmful effect by one plant (including micro-organisms) on another through the production of chemical compounds, known as allelochemicals, that escape into the environment.1 Chemicals that

• Word count: 5700
• Level: AS and A Level
• Subject: Science

#### Plan and carry out an experiment to investigate Osmosis in Potato tissue

Plan and carry out an experiment to investigate Osmosis in Potato tissue Planning Aim: To investigate osmosis in Potato tissue and find its water potential, using eight different molarities of sucrose Hypothesis Osmosis is defined as the net movement of water or any other solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. 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. Apparatus Test tube Label Sucrose solution Potato tissue 8 x test tubes 8 x potato chips 8 different sucrose solutions labels top pan balance test tube rack Method In each test tube, put 30cm³ of each solution of sucrose, and label it with the molarity of the sucrose that is in that tube, this is needed because otherwise you would not be able to plot the graph at the end showing how the molarity of the sucrose directly effects osmosis, or if the different molarities become mixed, anomalies will appear in your results. There are

• Word count: 1925
• Level: AS and A Level
• Subject: Science

#### Compare and Contrast the Transport System of a Mammal and a Plant

Compare and Contrast the Transport System of a Mammal and a Plant Introduction: Both mammals and plants require a transport system to satisfy the requirements of rapid supply of nutrients & gases, as well as the removal of waste products. Due to their huge surface area, transportation of substance is not quick enough if rely solely on diffusion, therefore a transport system is needed. A transport system relies on the mass flow movement of fluids due to pressure difference. The Mammalian Transport System: Mammals are metabolically active and have high nutrients demand, therefore a cardiovascular system is used to satisfy the need. This consists of a four-chambered heart and a system of interconnecting tubes (i.e. blood vessels) where blood is moved through them to the rest of the body. Mammal has a closed double circulatory system, which consists of pulmonary circulation going to the lungs and systemic circulation going to the rest of the body. With two circuits, a higher pressure blood can be achieved going to the body to form tissue fluid and deliver respiratory gases more quickly. A slower blood flow is desired when going to the lungs to allow more time for gas exchange and prevent damage on lung tissues. Blood never leave the vessels during transport so that a quicker blood flow rate can be obtained and this also allows vasoconstriction or vasodilatation to occur. The

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• Word count: 1179
• Level: AS and A Level
• Subject: Science