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
An Investigation Into What Affects How Much Copper Is Deposited On A Pure Copper Cathode.
An Investigation Into What Affects How Much Copper Is Deposited On A Pure Copper Cathode. Plan Aim The aim of this investigation is to find out what effects the amount of copper deposited on a pure copper cathode. We already know that by passing an electric current through a copper sulphate solution the atoms at the anode dissolve while at the cathode positive ions are gathering and collect up. Variables Variables are what we can change in the experiment here are some of them: * We can change the amount of current passed through the electrodes. * We can change the strength of the solution by adding and reducing the amount. * We can also vary how long the experiment is left while an electric current is passed through the electrodes. We choose to change the amount of current passed through the electrodes using a variable resistor. I choose this because it is simple and gives off good and clear results. Predictions A simple prediction would be to say that the mass of copper deposited at the anode would decrease, and the mass of copper deposited at the cathode would increase. It is also possible to predict when using time as a variable, that the relationship between the time the current flows and the mass of copper deposited at the cathode will be proportional. I can then predict that if I double the time of the experiment, I will be doubling
Research question - Is using dogs for work ethical?
Dog behaviour CDA Introduction There are many ways that animals are connected to our lives. Some of us have them as pets, and even people who don't have a pet still have products (such as medicine) that have been tested on them. According to a website called 'The vegetarian site' very well known companies such as 'Max factor', 'Vaseline' & even 'Kleenex' have products that are animal tested. Some people protest that animal testing is not ethical because of the pain the animals have to endure for our benefit, but others argue that a lot of the medicine we have now wouldn't of existed if it hadn't of been so. A lot of argument has also gone into the concept of conditioning. We condition animals and even people without noticing we are doing it. Dogs are trained to sniff drugs in an airport and even children have a daily bed time that they are used to. So when J.B Watson sprung a debate about ethics when he conditioned Little Albert (who was just a baby at the time) to be afraid of rats and other things that looked similar, he had opened a controversy. Does there have to be pain to gain? Or will we ever find out if a dog thinks it is ethical for itself to be entered into a race? We were studying at school the behaviour and characteristics of animals that are similar to those of human beings alongside the ethics to support the current world debates & trends. This particular
What is DNA?
DNA DNA, otherwise known as deoxyribonucleic acid has changed our lives, including our perception of life, by both scientists and the average person. Science has developed dramatically due to the discovery of DNA. DNA was first discovered by the Swiss physician Friedrich Miescher and Gregor Mendel who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of cells, he called it "nuclein". In 1919 this discovery was followed by Phoebus Levene's identification of the base, sugar and phosphate nucleotide unit. Levene suggested that DNA consisted of a string of nucleotide units linked together through the phosphate groups. However, Levene thought the chain was short and the bases repeated in a fixed order. In 1937 William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure. In 1943, Oswald Theodore Avery discovered that traits of the "smooth" form of the Pneumococcus could be transferred to the "rough" form of the same bacteria by mixing killed "smooth" bacteria with the live "rough" form. Avery, along with coworkers Colin MacLeod and Maclyn McCarty, identified DNA as this transforming principle.DNA's role in heredity was confirmed in 1953, when Alfred Hershey and Martha Chase in the Hershey-Chase experiment showed that DNA is the genetic material of the T2 phage. In
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
Cloning pros and cons
Cloning A group of genetically identical offspring produced by asexual reproduction is called a clone. The nucleus of every cell of an individual contains the genetic information needed to develop the entire organism. It is therefore possible under suitable conditions to produce a whole organism from a single cell. If a cell divides mitotically it will produce a clone. If each cell of the clone is separated and allowed to develop into the complete organism, a group of genetically identical offspring is formed. This is known as cloning. (2). Two very different procedures have been referred to as "cloning": * Embryo cloning has been successfully carried out for years on many species of animals. Some limited experimentation has been done on human embryos. * Adult DNA cloning has been used to clone a sheep, but was not tried on humans until 1998-DEC (3) Humans often think of themselves as being superior to other animals (not to mention plants, fungi, bacteria and so on) and therefore having the "right" to exploit other organisms for their own benefit. (1) The cloning of the sheep, Dolly, in 1997 was an inevitable consequence of the progress being made in genetics and biotechnology. It raises the possibility of breeding many identical copies of animals including transgenic animals, showing desirable features. One of the ethical concerns is that the techniques could be
How does the concentration of a sucrose solution affect the rate of Osmosis in Potato Cells?
Jennie Lace 10c How does the concentration of a sucrose solution affect the Rate of Osmosis in Potato Cells? PLAN I have chosen to investigate how the rate of osmosis taking place in potato cylinders varies when I change the concentration of the surrounding sucrose solution. I will vary the concentration of sucrose in the solution, and carry out various measurements on the potato cylinders before and after the experiment, to see what affect changing the concentration has had. I predict that with the lowest concentration of sucrose, the potato will increase in mass, because of water moving into the cells. The percentage increase will then get smaller each time I increase the concentration of sucrose in the solution. At some point, the mass of the potato will not increase, and will be the same as it was before (when there is no net flow of water particles in or out of the potato cells). After this, the mass of the potato will start to decrease as I keep on increasing the concentration of the sucrose solution. At some point the potato cylinders will lose all the water that they are able to, and the percentage mass loss will stop decreasing. This is what I expect the graph of my results to look like: Osmosis is the movement of water particles from a weak solution (a hypotonic solution) to a strong solution (a hypertonic solution. It happens through a selectively
Testing the biochemicals present in apple and green bean using specific chemical tests.
Biology Experiment Report Aim: To identify the biochemical and compare their contents in apple and green bean using specific chemical tests Principle of method: Carbohydrates, proteins and lipids are the major organic constituents of organisms. Thus they are often called biochemicals. The specific tests for reducing sugar, starch and protein are Benedict Test, Iodine Test and Biuret Test respectively. Before a specific chemical test can be carried out, it is necessary to extract juice from the tissue under investigation. Extraction method is very common in biological investigation. . Benedict's test for reducing sugars Benedict's solution contains copper sulphate. Reducing sugars reduces copper(II) ions present in the blue copper sulphate solution into insoluble brick-red copper(I) oxide which is a precipitate. Note. The initial blue colouration of the mixture turns green, then yellow and may finally form a brick-red precipitate. The final colour and amount of precipitate gives a rough indication of the amount of reducing sugar present. 2. Iodine test for starch Iodine solution is a mixture of iodine and potassium iodide solutions. Starch combines with iodine to give the characteristic of blue-black colour. Note. The positive result may be confirmed by boiling the mixture in a hot water bath for a few minutes and the blue-black colour disappears. On cooling the
