Investigate the water potential of a potato tuber.
My aim in this investigation is investigate the water potential of a potato tuber. This investigation needs a lot of planning and prediction with the use of scientific knowledge involving preliminary experiments, which will guide me for the main experiment to be successful and for it to produce concise and accurate results to prove the hypothesis, explained in the prediction. The main theory used in this experiment is the theory of osmosis, which is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration (http://www.purchon.com/biology/osmosis.htm). Osmosis controls the exchange of molecules through the semi permeable membrane. It allows small molecules like oxygen, water, carbon dioxide, ammonia, glucose, amino acids, etc. to pass through. Cell membranes will not allow larger molecules like sucrose, starch, protein, etc. to pass through. If the solution surrounding the cell has a higher water concentration than the cell (a very dilute solution) the cell will gain water by osmosis and vice versa. A key feature of osmosis is that only water molecules move across the membrane to bring the two solutions to and equilibrium. This equilibrium is reached when the water potential in one region is the same as the other region. Water potential is the chemical potential (i.e. free energy per mole) of water
How do different concentrations of sucrose solution effect potato tissue.
Osmosis Investigation Aim How do different concentrations of sucrose solution effect potato tissue. Background Information Osmosis is the movement of water molecules though a partially permeable membrane from an area of high water potential to an area of low water potential. The membrane lets small water molecules pass though but not large ones. The flow continues until the concentration becomes the same on the inside as on the outside. This is called equilibrium. Molarity is a measure of concentration. Prediction I predict that the potato will change in mass and in length. I believe this because each Molarity of sucrose will change the potato's water content. This will happen because either the concentration will higher in the sucrose and lower in the Tubas or lower in the sucrose and higher in the Tubers. Therefore water will travel in or out of the potatoes cell though its partial permeable membrane. Apparatus list * Boiling Tubes * Sucrose solution * Stop watch * Pipette * Test Tube Rack * Distilled Water * Potato * Potato Borer * Top Pan Balance * Ruler Preliminary Method * I will firstly get 10 test tubes and to test tube racks * Then I will cut 9 pieces of potato * I will then get 3 different Concentrations of sucrose solution and add 20cm3 to each test tube * Cut a 4 mm in diameter tuba to 1 cm in length * Now I will
Undertake an experiment to understand the effect of varying sucrose concentration on osmosis in potato chips, and to try and find where incipient plasmolysis lies between these experiments.
Biology Coursework Aim Undertake an experiment to understand the effect of varying sucrose concentration on osmosis in potato chips, and to try and find where incipient plasmolysis lies between these experiments. Background Knowledge Osmosis is the movement of water molecules from regions of high water potential to regions of lower water potential through a semi-permeable membrane until equilibrium is reached. Semi-permeable membranes hold back larger molecules that water, not allowing them through, and this is particularly important in plant cells for maintaining turgor. Plant cells are surrounded by a cell wall, and cell walls are fully permeable which means that it will let any molecules through it; therefore osmosis will not occur across it. A plant cell also has a cell membrane, and just like an animal cell it is selectively permeable. A plant cell, in the same way as an animal cell, will take in the water by the process of osmosis through its selectively permeable cell membrane if placed in pure water. As the water enters the cell, the cytoplasm and vacuole will expand and swell. However plant cells have a very strong cell wall. Cell walls are a lot stronger than cell membranes, and they stop the cell from bursting. When there is a higher water potential outside the cell and a lower water potential inside, and water has entered the plant cell through the
Investigation on the effect of osmosis in plant tissue.
INVESTIGATION ON THE EFFECT OF OSMOSIS IN PLANT TISSUE AIM: To investigate the effect of osmosis in potato tissue through turgor and plasmolysis. APPARATUS: 18 test tubes, 2 test tube racks, 3 potatoes, 5mm cork borer, electronic weighing scales, stopwatch, measuring cylinder, scalpel, thermometer, cutting board, 200ml of molar sugar solution and 500ml of distilled water. METHOD: ) Place one of the potatoes on a cutting board and insert the cork borer into it, whilst keeping it steady. After the borer has been pushed about 5cm into the potato, remove it and extract the tissue using a pencil. Repeat this procedure a further 17 times to obtain 18 potato tissue cylinders. You may require the other two potatoes. 2) Weigh the potato tissue cylinders on an electronic scale and cut them if necessary, using a scalpel, until their masses are equal or similar. 3) Take three of the test tubes and label them 'A'. Then fill them with 20ml of water and place them in the test tube rack. Next label the other three test tubes 'B' and fill them with 20ml of a 0.2 molar concentration sugar solution. To do this, simply add 16ml of distilled water and 4ml of the molar sugar solution to the test tubes. Place these in the test tube rack. 4) Follow the basic procedure mentioned in 3) labelling another four sets of three test tubes 'C', 'D', 'E' and 'F'. Fill these with sugar solutions of
To investigate the effect of the concentration of starch on an amylase controlled reaction
Aim: To investigate the effect of the concentration of starch on an amylase controlled reaction Introduction (Background Knowledge): I am going to be investigating the effect of the concentration of starch on an amylase controlled reaction. Amylase is a type of digestive enzyme, which is usually found in a human's saliva and small intestine to help digest starch and other long-chained carbohydrates engulfed. An enzyme is a macromolecule (a molecule with a large molecular mass) and a protein that catalyses, or speeds up, a chemical reaction. Enzymes work effectively due to their complex structure and shape. The section of an enzyme where the reaction(s) and combining with reactants (or substrates) take place is called the 'active site'. The enzyme allows the products to form from the substrate by making and breaking chemical bonds easily (and in this case, the starch bonds will be broken). Enzymes are 'recyclable', meaning that they are not used up at the end of reactions and can be used again to combine with other substrate molecules, and thus forming more products. Enzymes are usually specific as to the reactions they catalyze and the substrates that are involved in these reactions. Shape, charge and complementarities of enzymes and substrates are responsible for this specificity. An enzyme is linked to a specific key that fits into a specific substrate - the lock. This
biology-life on mars?
The idea that life begun on mars and travelled to earth is sometimes called panspermia. Here is the definition: Panspermia is a hypothesis that the seeds of life are prevalent throughout the Universe, and furthermore that life on Earth began by such seeds landing on Earth and propagating. The idea has its origins in the writings of Anaxagoras, but was first proposed in its modern form by Hermann von Helmholtz in 1879. Panspermia can be said to be either interstellar (between star systems) or interplanetary (between planets in the same solar system) There is as yet no compelling evidence to support or contradict it, although the majority view holds that panspermia - especially in its interstellar form - is unlikely given the challenges of survival and transport in space. For * "It's surprisingly easy to get material from Mars to Earth," says Gladman. "If you launch stuff off Mars, there aren't a lot of other places to go." He found that up to 5 percent of the rocks launched from Mars land on Earth within 10 million years. Many arrive much sooner- some within a few years. * The next question: Could microbes aboard survive ejection and impact? To escape a planet's gravity, a rock must accelerate from zero to at least 11,500 miles per hour in a thousandth-of-a-second jerk so intense it would liquefy a human. But when Jay Memos and his colleague Rachel Mastrapa loaded bacteria
What is AIDS?
AIDS is short for "Acquired Immune Deficiency Syndrome", and is a viral infectious disease. It is a surveillance definition based on symptoms, infections and cancers associated with the deficiency of the immune system that stems from infection with HIV. AIDS has been haunting the world for the past two decades, killing millions of people and showing no signs of resignation. The disease frightens us not only because it's fatal, but also because its insidious time course makes us all potential carriers before it hands our heads in a basket. Human Immune Deficiency Virus (HIV) is the pathogen that causes AIDS. HIV is a retrovirus that selectively infects helper T cells, and destroys or impairs their function. HIV particles are usually round and have a diameter of about 85-95nm. The virus is notorious for its ability to mutate and change shape regularly, and thereby evade the effects of drugs and elude detection from the human immune system. There are two species of HIV - HIV 1 and HIV 2. HIV 1 is more common, more virulent, and more easily transmitted, whereas HIV 2 is weaker and mostly confined to West Africa. Viral envelope - Viral envelopes are used to help the virus enter host cells, and to protect the virus from nuclease enzymes in the host fluids. It may be composed of lipids, proteins, or carbohydrates. Nucleic acid - Nucleic acids in the form of DNA and RNA control
Investigating Osmosis in Potato Tissue.
Investigating Osmosis in Potato Tissue Aim To estimate the concentration of sucrose in potato tissue. Hypothesis I believe that the potato tissue that has been in the hypotonic (0.1M sucrose) solution will be more turgid than before, while the tissue in the isotonic (0.3M sucrose) will be similar to its previous state. The tissue that has been in the hypertonic (0.5M sucrose) should be far more placid than it was before. This is because of osmosis - water diffusing in and out of the potato tissue cells. Apparatus * 1 potato tuber * 1 cork borer * 1 ceramic tile * 1 scalpel * Paper towels * 6 boiling tubes * 1 marker pen * 0.1M, 0.3M, and 0.5M sucrose solution * Access to an electric balance * 1 funnel Method The volume of each boiling tube was calculated, and then 2 tubes were half-filled with 0.1M sucrose solution, 2 tubes were filled with 0.3M sucrose solution, while the final 2 tubes were filled with 0.5M sucrose solution. Then 6 cylinders of potato were cut from the tuber using the cork borer. These were then all cut down to 20mm in length using the scalpel. They were then dried with the paper towel to remove excess water before being weighed on the electric balance. The weight of each was recorded. They were then all immersed in the solution in the boiling tubes, and the tubes were labelled using
My aim in this experiment is to find out how osmosis affects potato chips' mass when placed in different concentrations of glucose and water.
An Investigation into Osmosis Aim: My aim in this experiment is to find out how osmosis affects potato chips' mass when placed in different concentrations of glucose and water. Prediction: I will now predict how I think the outcome of the experiment will be. I believe that some of the potatoes will shrink and lose weight, some will swell and gain weight and some will stay the same. I think that when there is a high concentration of glucose, osmosis will occur through the potato and it will shrink as water molecules escape into the solution. When there is a very low concentration of glucose I believe the potato will swell as it gains water molecules due to osmosis trying to equal out the balance of water. I find it unlikely that any of the potatoes will stay exactly the same weight but some that are in the middle concentrations like 0.4 and 0.6 may change only slightly. However, there will be a point where the concentrations of water inside and outside the potato cells are equal (isotonic). At this point there will be no change in the length, volume and mass of the potato, as the net movement of water will be zero, no osmosis has occurred. Using this information a graph and prediction can be made. At point A the graph suggests that no osmosis has occurred, suggesting that the concentration of water inside the cell is equal to the solution outside. At point B (high
An investigation into the effect of substrate concentration on the release of oxygen from hydrogen peroxide by catalyse in potato tissue.
An investigation into the effect of substrate concentration on the release of oxygen from hydrogen peroxide by catalyse in potato tissue. Introduction. A catalysts is a substance which speeds up a chemical process. Enzymes work best at optimum conditions, temperature and pH for example. This is because they are made out of protein. A certain enzyme is pacific to a certain reaction and cannot be used in any other reaction as it's shape and design is purely for one reaction. In a reaction the enzyme joins with the substrate, (the substance acted upon) to produce the complex. The enzyme has a fixed shape which connects with a certain substrate, this method is often referred to as lock and key as the enzyme and substrate fit together perfectly, much like a lock and key. The reaction depends on the fact that they fit together and if the enzyme is slightly disfigured or denatured then no change will be produced. This means that only a certain type of enzyme can fit a certain type of substrate. Once the bond has been made a reaction can take place. This is demonstrated in the diagram below: For a reaction to take place the substrate and enzyme must make contact, therefore if more heat is applied to a mixture of enzyme and substrate the more energy the molecules have , the more they move around and therefore more collisions take place. This means there are more reactions and
