• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Biology Coursework

Extracts from this document...


PLANNING INTRODUCTION- During this investigation I am going to find out how osmosis affects potato cells. Osmosis is the diffusion of water -or any other solution- through a semi-permeable membrane, from a region with high water concentration to a region with a low water concentration. The movement will take place across a cell wall- a semi-permeable membrane; in this case the potato cell, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. So I will investigate this by using 5 slices of potatoes of the same mass and inserting them into 5 different concentrations of a sugar solution. At the end of the investigation I hope to see how much of the sugar solution is absorbed into the potato slices. EQUIPMENT- * 3 potatoes * Scales * Ruler * Knife * Chopping slate * 10 Test tubes * 2 Test tube racks * 5 concentrations of a sugar solution. (Ranging from 0%-10%) METHOD- I will set up 10 test tubes, because in order to save time, I intend on doing the test twice so that I can calculate the average result, making it more accurate. After I set up the ten test tubes in the two test tube racks (5 each) I will label each test tube. Both racks will have a test tube labelled 0%, 2.5%, 5%, 7%, 10% and either test 1 or test 2. ...read more.


Room temperature is roughly 20 degrees Celsius. The length and mass of the potato slices are a prime factor in the experiment. The lengths and mass of the potato slices have to be the same in order for the experiment to be a fair test; these variables shall not be changed unlike the concentration. PREDICTION- I predict that the lower the concentration the sugar solution is, the larger the mass of the potato slice shall be, because more water will be diffusing into the potato if the concentration of the solution is lower than that of the potato. Also, the higher the concentration of sugar solution is, the less the potato slice shall weigh because water will be diffusing through the potato into the solution as it has a higher concentration then the potato has. Also the longer the potato slices are inside the sugar solution the more water shall be diffused by the potato slice either increasing the mass of the potato or decreasing it. OBSERVING Recording- In my results table I will show that the mass of the potato before the experiment and after. I will also show if it was Test 1 or 2 and the concentration of the solution as well as the change in mass. Units- The units for my results will be grams (g) ...read more.


EVALUATION Reflecting- My experiment worked well because I managed to get an average result making it more accurate. There were no anomalies in my table or my graph. I know my results were reliable because it was a fair test and as I did each test twice and made sure the mass of the potatoes in grams were the same making it more accurate. I could improve the experiment by maybe doing it three times instead of two so that I would have a better average result, making it more reliable. I would describe my experiment as being successful because it does show that as the concentration of the sugar solution increases, the mass of the potato slices decrease and when the concentration of the sugar solution decreases the mass of the potato slice increases. Therefore I can say my conclusion is that the higher the concentration of the sugar the more the mass decreases, this is because the water present in the potato diffused through the cell wall and into the sugar solution as it is a region of lower water concentration. I know this because in my experiment the opposite happened to the potatoes placed in the lower concentrations of the sugar solution; the potatoes gained mass because the potatoes had a lower concentration of water then the solution so water molecules diffused through the cell wall and into the potato. The support and evidence for my conclusion comes from my results table, graphs and scientific explanation. ?? ?? ?? ?? BIOLOGY COURSEWORK ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Peer reviewed

    Osmosis in potato and apple

    3 star(s)

    More results are needed for a solid reliable conclusion; therefore I will be using 5 chips for each concentration of salt solution, of each plant tissue. The null hypothesis is that there is no difference in water potential between apple and potato.

  2. Photosynthesis coursework

    This is measured by a greater amount of oxygen bubbles being produced. Method Input variables - light intensity is to be varied by increasing and decreasing the distance from the light source to the plant Output variables - volume of oxygen produced (rate of photosynthesis)

  1. Free essay

    Biology Coursework

    then use forceps to hold the leaf and transfer it into the beaker containing 20 cm of hot water.. Step 3: Add approximately 5 cm of ethanol in each test tube and place each of the leaves in it. The ethanol will destroy the chlorophyll on the surface area of the leaf.

  2. Science Coursework

    In this graph you can see that at a lower temperature the rate of photosynthesis is increasing with increasing light intensity and/or carbon dioxide availability. However the CPS/LSP is quickly reached. So the plant cannot photosynthesis at an accelerating rate anymore.

  1. Investigate the cell sap concentration of solute in a potato chip using osmosis and ...

    the duration of the experiment and all the equipment used will be kept the same. It is predicted that the chips in 0% solute concentration will gain in weight by roughly 10% - 15% estimated by comparing the two lines of best fit from the predicted graph and the pre-test graph.

  2. Change in mass of potatoes in different concentrations of sugar solution.

    The outer layer of the cell is a very thin cell membrane, which is semi-permeable. It can be avoided as the mitochondria provide energy from respiration to the contractile vacuoles to squeeze excess water out of the cell. This process of regulating cell fluid to keep it at a constant concentration is called osmoregulation.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work