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

Osmosis/ Diffusion Lab

Extracts from this document...


Riley Lambertsen Osmosis/Diffusion Lab Date: 11/20/08 Design: Research Question: How will a hypotonic solution (distilled water) affect osmosis and diffusion of a solution of starch and glucose in a dialysis (semi- permeable) membrane? Hypothesis: In a hypotonic solution, water concentration is greater outside the membrane than inside. Therefore, water will flow into the bag and the mass of the bag will increase. Glucose will diffuse out of the bag because it is a small molecule and the concentration of glucose is lower outside the bag than inside. Benedict's solution will determine if this occurs. Starch is a large molecule and will remain in the bag regardless of the concentration gradient. This is due to the fact that the starch molecules are too large to pass through the pores of the dialysis membrane. Iodine will determine if this is true. Relevant Variables: Independent variable- diffusion of water, starch, and glucose. Dependent variables- mass and color changes. Other relevant variables- concentration, size of molecules, pore size of dialysis membrane, temperature, security of bag closure. ...read more.


Test the water in the beaker for glucose by adding 15 drops of Benedict's solution. Heat the water for the Benedicts test. If the water turns bright orange, then glucose molecules are present. 11. Record your results in the data table. Sufficient Data: 7 � 1 Data Collection and Processing: Data Collection Table: Mass of Dialysis Membrane and Color Change Tests Before Weight (gm) After Weight (gm) Color Change w/ Iodine Color Change w/ Benedicts. Sample 1 42.63 44.40 None Bright orange Sample 2 36.87 37.86 None Bright orange Sample 3 40.46 41.37 None Bright orange Sample 4 33.34 34.96 None Bright orange Sample 5 40.61 42.58 None Bright orange Sample 6 30.81 32.19 None Bright orange Sample 7 42.00 43.30 None Bright orange Differences Between Before and After Weight of Bag Mass Gained(gm) Sample 1 1.77 Sample 2 0.99 Sample 3 0.91 Sample 4 1.62 Sample 5 1.97 Sample 6 1.38 Sample 7 1.30 Data Processing: Standard Deviation of "Mass Gained": X M X- M (X- M) ...read more.


Because it did not, we know that the starch is still in the membrane and couldn't diffuse through. Then 15 drops of Benedict's solution was added and the water was boiled. The beaker turned bright orange, indicating that glucose was present and had diffused through the membrane. Thus, I accept my hypothesis on the basis of my data. Evaluation of procedure: The experiment itself was fairly simple, and didn't have any major problems. The only areas that could really be improved were the starting mass of the solution- filled membrane, and the timing of the lab. If complete specificity was wanted then the amount of hypotonic solution could also be predetermined and regulated. Improving Procedure: The starting masses of the solution- filled membranes were all different. This was due to unspecific measurements and simply judging "how much". As well, the trials were not all conducted for the same period of time. There was a margin of error of about � 2 minutes. To remedy these problems, a regulated amount of solution and a better timer could be used. Also the amount of hypotonic solution should be regulated to decrease the percent error. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology 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 International Baccalaureate Biology essays

  1. Biological Membrane Lab

    Group 1 Group 2 Group 3 Group 4 Average 0 0.118 0.070 0.060 0.104 0.088 10 0.146 0.081 0.088 0.143 0.114 20 0.579 0.091 0.090 0.442 0.300 30 0.330 0.448 0.059 0.487 0.331 40 0.930 0.521 0.694 0.730 0.718 Table 2: The amount of damage various alcohols cause to cell membranes at a given Concentration.

  2. The effect on osmosis on the egg shell

    "height" of solution varied, this affected degree of submergence Weaknesses (note that more significant weaknesses will be indicated with "s")

  1. Plant Tropism Lab

    - - T-1 - - - - - - T-2 - - - - - - T-3 - - - - - - T-4 - - - - - - T-5 - - - - - - K-1 - - - - 70 80 K-2 - - - - -

  2. Biology Lab Design Glucose concentration

    Fruit Reading 1 (%) Reading 2 (%) Reading 3 (%) Reading 4 (%) Reading 5 (%) Reading 6 (%) Reading 7 (%) Apple 1 1 1 1 1 1 1 Pineapple 5 2 1 1 1 1 1 Passion Fruit 66 62 41 63 1 58 63 Orange 1 1

  1. Bio lab - Oxygen Consumption in germinating and non-germinating seeds

    The slope of the germinating seeds at room temperature is the steepest and the slope of the non-germinating seeds in ice water is the flattest. The negative value on the y-axis should be ignored because there can't be any negative values are the oxygen consumption value.

  2. Osmosis Lab

    The fifth and final set of results will contain 100 grams of salt in the beaker. 4. Stir the salt with a stirring rod until the salt completely dissolves. 5. Cut out 14cm of cellulose tubing with scissors. Cut out 5 of these, one for each beaker.

  1. Beet Lab. Aim: To determine the effects of temperature on the permeability of ...

    When the temperature rises, the molecules have increased kinetic energy which means that the phospholipids and other substances move around more, making the membrane more 'leaky' which means that substances that wouldn't usually do so can enter and leave the cell.

  2. Effect of Detergent on Membrane Permeability

    of beet, such as using a cork bore, or cut the beet electronically, to make sure that they have the same size and shape. Then, we could measure its mass and volume, to make the result even more accurate. The temperature could have been lowered as well, because beetroot tends

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