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

Investigating and testing for reducing and non-reducing sugars

Extracts from this document...

Introduction

Biology - Experiment write up Investigating and testing for reducing and non-reducing sugars Aim: To use techniques to test a selection of known and unknown substances, to determine whether or not they are a reducing, non-reducing sugar or neither. Prediction: In the first part of the experiment (simple Benedict's test), I predict that out of the three solution samples; glucose, sucrose and sample X, only glucose will change from the blue colour. I do not know what the substance in sample X is and therefore cannot comment on the outcome. However in my opinion sucrose will not change colour during this part of the experiment. In the second part of the experiment, when using acid to break any glycosidic bonds and sodium hydrogen carbonate to neutralise the solution, I predict that sucrose will change colour. In my opinion the part of the experiment will make no difference to the glucose and therefore the outcome to this second part will be the same as part one of the experiment. ...read more.

Middle

The colour determines the amount of reducing sugar... Blue Green Yellow Orange Red Browny Method: * Firstly I collected the apparatus that I would need for the experiment, using the syringe, I measured out, as accurately as possible 2ml of each sample of solution and put it into 3 separate test tubes. * After, I placed the test tubes into the test tube rack and carefully boiled some water, which I then poured into the beaker. * Using the pipette, I tried to put as equal as possible, amounts of Benedict's solution into each test tube. I then placed all of the tubes into the beaker of hot water and recorded any colour changes. * As the glucose changed colour I know only needed to perform the second part of the experiment on the sucrose and X samples. * I washed out the test tubes and again using the syringe measured out equal quantities of each solution, and placed the tubes back in the rack. ...read more.

Conclusion

ion straight away with simply testing with Benedict's solution only. The glucose is therefore a reducing sugar, as the colour of the blue copper sulphate changed to an Orangey red without the sample's bonds needing to be broken down. Sucrose on the other hand, did not reduce the copper sulphate in the first part of the experiment as the colour of the solution did not change at all. I could therefore tell that the sample sugar, sucrose was not a reducing sugar. After completing the second part of the experiment the colour changed. This means that sucrose is a non-reducing sugar. Solution X unlike the other two samples showed no colour change in either experiment. This therefore means that this sample is not a sugar. To improve this investigation I would repeat the experiment another two times, to ensure accurate results. I could also use a more accurate to measure the quantities of the liquids used. For example, by using a liquid level sensor. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

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

Here's what a teacher thought of this essay

3 star(s)

An adequate report of an investigation into the identities of three food samples. The writer has correctly described the appropriate sugar tests and draws relevant conclusions. However, to fully satisfy 'A' level requirements, the report needs to describe the methods used in more detail with special attention to volumes, times and temperatures. It would have been helpful if the writer had given details of the chemistry behind the Benedict's test (donation of electrons, etc.) and exactly why glucose is - and sucrose is not - a reducing sugar.

3 stars

Marked by teacher Ross Robertson 19/06/2013

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 AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Mr Chips: Investigation to find an isotonic solution for potatoes

    4 star(s)

    The specific trend visible in the graph is a dramatic decline, dropping from a positive increase in mass to a negative decrease in mass. Proving again that the water potential within the potato cell was negative but only slight as the intake of water down the gradient was minimal.

  2. Marked by a teacher

    An Investigation into the Water Potential Of Root Vegetables.

    4 star(s)

    Another point made in my prediction, which has been proved correct by my experiment, is that out of the five sucrose solutions, more were hypotonic solutions for the swede than for the potato. This means that the swede gained mass in more of the solutions because they were at a higher water potential than the potato.

  1. Marked by a teacher

    Reducing and non-reducing sugars tests.

    3 star(s)

    BLUE B RED C BLUE D GREEN I therefore did the NON-REDUCING sugars test with solutions

  2. To compare quantitatively the concentrations of glucose and other reducing sugars in samples of ...

    Concentration (% glucose) Colorimeter reading Mean colorimeter reading 1 2 3 4 2 1 0.5 0.25 0.125 0.0625 In order to convert % concentration into mg cm-3 using 1 cm3 of solution, you must multiply the % by 10 e.g. there would be 40 mg cm-3 of glucose in 1 cm3 of 4% glucose solution.

  1. Fermentation of different sugars by yeast.

    Fill up the rest of that barrel with 2.5 cm3 of yeast suspension. 3. Gently rotate the barrel so that the solution is mixed properly. 4. Connect the syringe with the rubber tubing. 5. Now connect the rubber tubing with the capillary tubing so that syringe is connected with the tubing.

  2. An investigation to see whether the concentration of Sucrose effects the amount of Carbon ...

    I did encounter a few anomalous results. They were all similar though. One of these similar anomalies was that between the first and second day of the experiment the mass lost for the 1% concentration solution was 1.61g and the mass lost for the 20% concentration solution was 0.45g.

  1. To find out the factors affecting the refractive index of liquid by using different ...

    Then measure the horizontal distance between the light source and this initial mark of the A4 paper. Then measure the vertical distance between the base of the container and the light source. Use a 200ml beaker, measure 200ml of the solution that I am testing on.

  2. Investigation on Osmosis using a potato.

    (o.333') 20 ml water 10 ml 1M sucrose solution. 1.45 1.54 6.21 1/2 Molar sucrose solution. 15 ml water 15 ml 1M sucrose solution. 1.39 1.42 2.16 2/3 Molar sucrose solution. 10 ml water 20 ml 1M sucrose solution. 1.42 1.32 -7.04 0.8 Molar sucrose solution. 5 ml water 25 ml 1M sucrose solution.

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