The effect of caffeine on heart rate
Core Practical 1.1 the effect of caffeine on heart rate Aim: The aim of this experiment is to investigate the effect of different concentrations of caffeine on the heart rate of Daphnia (water fleas). Hypothesis: I predict that the concentration of caffeine will affect the heart rate. I believe this will be directly proportional to each other. For example, as concentration of caffeine in the blood increases, the heart rate of the daphnia will also increase. Caffeine is a drug that is classed as a stimulant because it stimulates the body's systems. It increases the activity of the neurotransmitters in your body which speeds up your heart rate, thus blood is pumped faster around the body. Variables: The dependant variable being observed and measured was the number of heart beats per minute of the Daphnia (water flea).The independent variable in this experiment was the concentrations of caffeine 0.5%, 0.6%, 0.7%, 0.8%, 0.9% and 1%. Fair Testing: To make it a fair test: we kept the timing the same for each condition; the environment for the daphnia were kept the same; the type daphnia was kept the same. This made the results valid as caffeine was the only variable that was manipulated in the experiment. Ethics: Since this experiment involves living organisms, ethical issues were raised. Consideration has been taken into account and the following guidelines were used:
Investigating Osmosis In Potato Cells
Investigating Osmosis In Potato Cells Introduction Osmosis is a form of diffusion but specifically for water, it is the diffusion of water from a dilute solution to a more concentrated solution through a semi permeable membrane. In this experiment we used water because in osmosis only water molecules can be used Prediction Tubes Predictions Explanation and 2 The mass and length will go up The concentration is less in the chip 3 and 4 The mass and length will stay the same The concentration is the same as in the chip 5 and 6 The mass and length will go down The concentration is more in the chip Method Apparatus * Cork borer * Scalpel * 6 boiling tubes * 6 potato chips * Distilled water * 2.8 M sucrose * Electronic scales * Ruler * Pen Firstly we cut 6 potato chips with a cork borer, and then we squared off the edges with a scalpel, so they were all the same size, so that it could be made a fair test. Next we labelled 6 boiling tubes: 1 to 6. Then we patted the chips dry, measured their length with a ruler and measured their mass on an electronic scale and recorded these measurements in a table (results). We filled the tubes with the required solution: Tubes 1 and 2: 0.4 M sucrose Tubes 3 and 4: distilled water Tubes 5 and 6: 1.0 M sucrose After leaving them for 3 hours we recorded how the mass and the length of the chips had changed and compared
Investigating respiration in yeast.
Investigating respiration in yeast I am investigating the respiration of yeast and finding the best conditions for producing carbon dioxide by breaking down glucose using yeast as the catalyst. Affecting factors There are factors that could affect the outcome of my investigation such as: > The temperature > The amount of yeast > Another factor that could affect our investigation is the percentage of glucose in the yeast. Fair test To make my investigation a fair test. I will use the same apparatus each time but washing and drying them out thoroughly so not substances from the previous experiments will be left. I will use as accurately as possible the same amount of glucose and yeast each time and using the same concentration. I must also make sure to leave all experiments undisturbed during the course of respiring, this means they cannot be stirred or let air get to them. I have chosen to investigate the affect the % concentration of glucose has on the rate of respiration in yeast as a preliminary experiment to find out which concentration will be the best to use. I will use an experiment to determine whether the yeast´s rate of respiration will be quicker, slower or if it does not change when the concentration of glucose is varied. Prediction I predict that the yeast´s respiratory rate of reaction should increase in speed as the % of glucose increases. However
Investigating Respiration in Yeast
Investigating Respiration in Yeast Aim To investigate the effect of different concentrations of glucose on respiration in Yeast. Introduction Yeast Yeast is simply a single-celled fungus, found on the surface of fruit, feeding on sugar. Yeast can multiply itself by a process called budding. A large number can be formed in a short time. Respiration Respiration is basically the breakdown of glucose to feed a cell, supplying it with energy. There are two types of respiration: aerobic and anaerobic respiration. Aerobic respiration requires oxygen to carry out, but anaerobic respiration does not need oxygen. Anaerobic respiration causes lactic acid, which contributes to cramp. The equation of aerobic respiration is: Glucose + Oxygen --> Carbon Dioxide + Water + Energy C6H12O6 6O2 6CO2 6H2O Experiment We can measure respiration with a simple experiment - which is the one I am doing. We measure the volume of Carbon Dioxide with different glucose concentrations. This gives us our results. Variables I will measure the rate of Carbon Dioxide produced. This is the dependent variable. I will change the concentration of glucose. This is the independent variable. Other variables have to be controlled as these can also affect the reaction. These are: Temperature, pH, Volume and Concentration of Yeast. Temperature This is a very important control variable because
Osmosis In Potato Cells
SCIENCE: Osmosis In Potato Cells Task In this experiment, our task was to investigate the effect osmosis had on the mass of a potato chip. Research: Osmosis is when the molecules move around a solvent, through a semi-permeable membrane, lowering the concentration of a solute on the other side of the membrane. The purpose of this is to match the two sides of the membrane, so they are balanced. This is caused by osmotic pressure, an irreversible type of diffusion. This is when molecules jump from one place with a high concentration to another with a low concentration. Diffusion is important for many things, especially in the human respiratory system, when the alveolar membrane of the lung separates the carbon-dioxide filled blood with the oxygen-rich air. Plan: To determine the rate of osmosis in a potato chip, we can treat a number of different chip specimens with different solutions. These are distilled water, 5% sucrose solution, 10% sucrose solution, and also 15% and 20% solutions. We shall be testing this experiment with thin slices of potato, which will be easier for the osmotic pressure to penetrate wholly, as opposed t just the exterior. We will know is osmosis has taken place because the potato chips will have changed in either mass or shape/size, as a result of the movement of the solution. This is because, if osmosis takes place, the sucrose molecules in the
Osmosis In Potatoes.
AT1- Osmosis In Potatoes Aim: Investigate the movement of osmosis through a selectively permeable membrane, in this case potato. Introduction: Osmosis is the movement of water through a semi permeable membrane, separating solutions of different concentrations. The water passes from a region of high concentration to a region of low concentration, until the two concentrations are equal in concentrations of water. Many cell membranes behave as semi permeable membranes, and osmosis is a vital mechanism in the transport of fluids in living organisms, for example, in the transport of water from the soil to the roots in plants. If a cell is in contact with a solution of lower water concentration than its own contents, then water leaves the cell by osmosis, through the cell membrane. Water is lost first from the cytoplasm, then the vacuole through the tonoplast. The living contents of the cell contracts and eventually pulls away from the cell wall and shrinks, this is known as Plasmolysis. If you put a plant cell in water, water enters by Osmosis, then swells up. However, the cell will not burst. This is due to the fact that the cell walls are made from cellulose, which is extremely strong. Eventually, the cell stops swelling, and when this point is reached, we say the cell is turgid. This is important, because it makes plant stems strong and upright. Osmosis diagram: Key:
Osmosis Investigation
Osmosis Investigation AIM: To investigate the rate of osmosis in potatoes with different concentrations of glucose. HYPOTHESIS: Osmosis is the net movement of water or any other solution's molecules from a place in which is highly concentrated to a place in which is less concentrated. This movement must take place across a particular permeable membrane such as a cell wall, which lets smaller molecules through being the water, 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 water molecules are randomly placed throughout the potato, with no area having a higher or lower concentration than any other. PREDICTION: I predict that the pieces of potato with the weaker concentrations of glucose will weigh less at the outcome of this experiment, than the potatoes with the stronger concentrations. This is due to the water molecules exchanging from a higher concentration, which is the glucose solutions, to a lower concentration, which is the potato. I predict this because, the higher the concentration of glucose that transports from a higher concentration to a lower concentration, the stronger the osmosis becomes. Therefore my prediction predicts that the weaker concentrations with the pieces of potato will weigh less than the stronger
Osmosis Investigation
Valentine Macau Osmosis Investigation INTRODUCTION: Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. Diffusion results because of the random movement of particles. The diffusion of water into and out of a selectively permeable membrane is called osmosis. Because of the selectively permeable membrane, nothing but water and other very small particles can be diffused through osmosis. The cell membrane is similar to the membrane mentioned above, so the cell would lose water because of osmosis if it were placed in an environment in which water concentration is greater than that of the cell. A solution is isotonic if the concentration of dissolved substances is the same as the concentration inside the cell. Osmosis does not occur in an isotonic solution. A hypotonic solution is a solution in which the concentration of dissolved substances is lower than the concentration inside the cell. If a cell were put in a hypotonic solution, osmosis will cause water to move through the cell membrane into the cell. A solution is hypertonic if its concentration of dissolved substances is greater than the concentration inside the cell. If a cell were placed in a hypertonic solution, it would lose water. All particles that pass through the plasma membrane by the process of diffusion do not
Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a partially permeable membrane.
Planning Introduction Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a partially permeable membrane. In this case, the tiny holes in the membrane of the potatoes will allow the water molecules to pass through in and out of the solution and the potato, depending on the concentration gradient of the two substances. So in this case, when the water concentration is lower in the tissue, the water will go inside the tissue of the potato, and the potato will grow in length, and if there is very little difference in the two water concentrations, there shouldn't be such a big change in length. If there is a higher concentration of water in the potato, the water will go out of the potato. Water molecules have random kinetic energy meaning they move around where they want and wherever they want. The potato, cut up into pieces, will need some sort of element to survive, and in this experiment, it would be light and water. With both of these sources, the potato will keep on working, until it dies of either lack of water, too much water. When the concentration gradient is lower in the potato, the water will transfer from the solution to the potato. The chip will not continue to grow in size because the cell wall will stop expanding when all the cells become turgid. When the change in length is 0 it means that the concentration gradient
Enzyme Concentration
Enzyme concentration Aim In this experiment, the purpose is to investigate how enzyme concentration can affect the initial rate of reaction. By doing this I will be able to develop experimental and investigate skills, including risk assessment. Hypothesis The effect of reducing the concentration of the protease enzyme on the rate of breakdown of the protein found in the milk powder is that the enzymes will run out of energy which will mean less milk powder will be broken down as they have smaller energy over the time. Equipment * Milk powder solution * Test tubes * Test tube holder * Stop clock * Standard protease solution 1% * 5cm? pipettes * Glassware for diluting enzymes Safety All enzymes are potential allergens. Handle with care to minimize skin contact and inhalation. Also wear safety gear such as goggles and aprons. Procedure * Pour 2cm? of protein solution into a cuvette using a pipette. * Then pour 2cm? of the protease solution in to a cuvette using another pipette. Mix carefully and quickly put into the colorimeter and start the stop clock. * Measure the absorbance every 30 seconds for 5 minutes or in till there is a little change in the reaction and record the result. * Get rid of the mixture and rinse the cuvette with distilled water. * After recording the result for every 30 seconds of all the 5 minutes plot a graph of the change in
