Page
  1. 1
    1
  2. 2
    2

Reducing and non-reducing sugars tests.

Do not show me this again

Are you in the right place?

Jump to Biology and see how teachers think you should prepare in:

Extracts from this essay...

Introduction

REDUCING and NON-REDUCING sugars tests. Aim: To distinguish which of the four unknown given substances are sucrose, maltose, glucose and water. Apparatus: Safety: For this experiment I made sure all the glassware was away from the edge of the table to avoid knocking them off and smashing them. Also I was careful whilst boiling the solutions and I was careful carrying to and from the water bath. I wore safety goggles throughout the experiment. Method: NON-REDUCING sugar. * Add 2cm of one of the unknown solutions into a test tube * Add 2cm of benedict's solution * Repeat this with each of the unknown solutions * Heat all the solutions in the water bath for 2 minutes Look at the colour of the solution if it remains the original blue colour of the benedict's solution then proceed with the test for REDUCING sugars.

Middle

A and C and then proceeded to the REDUCING sugars test the results were as following: SOLUTION COLOUR AFTER NON-REDUCING SUGAR AND REDUCING SUGAR TESTS A RED C BLUE From my results I can tell: SOLUTION NAME A SUCROSE B GLUCOSE C WATER D MALTOSE Conclusion: Reducing or non-reducing refers to whether a carbohydrate gives a positive or negative test towards the weakly oxidizing Cu in benedict's solution. All reducing sugars contain free or potentially free aldehde. Only sugars that can't open to the carbonyl form are non-reducing. The Benedict's test allows us to detect the presence of reducing sugars (sugars with a free aldehyde or ketone group). All monosaccharides (carbohydrates that can't be hydrolysed to simpler compounds)

Conclusion

We know that sucrose is made up of one glucose molecule and one fructose molecule glycosidicaly bonded. After hydrolysing to break the glycosidic bond to its constituent monosaccharides it then gave a positive test for reducing sugars (benedict's test). Solution B was glucose as it formed a red precipitate, which showed it was a monosaccharide solution. Solution C was water it also remained its original blue colour however after hydrolysing it still gave a negative test for reducing sugars (benedict's test). Finally, solution D was maltose as it left a green precipitate. Maltose is also a disaccharide, as previously explained not all disaccharides are non-reducing; however they are not as reducing as monosaccharides. My final conclusion is that the reducing sugars include all monosaccharides, glucose and fructose and some disaccharides, maltose. Tegan Gowlland

The above preview is unformatted text

Found what you're looking for?

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

Here's what a teacher thought of this essay

3 star(s)

***
The author has a sound understanding of the biochemistry behind this straightforward experiment. However, muddling up the tests for reducing and non-reducing sugars suggests that the finished write up was not checked. Greater attention to detail generally would have improved the quality.

Marked by teacher Adam Roberts 05/09/2013

Not the one? Search for your essay title...
  • Over 180,000 student essays
  • Every subject and level covered
  • Thousands of essays marked by teachers

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Investigating and testing for reducing and non-reducing sugars

    3 star(s)

    Redox Reaction Cu(( Cu(( Glucose is a monosaccharide. This means that the sugar solution is made up from many single sugar units that cannot be broken down into a simpler form. Monosaccharides are small, sweet, white, soluble and crystalline. Disaccharides are very similar, the are also small, sweet, white, soluble and crystalline.

  2. An Experiment Testing for Carbohydrates Non-Reducing sugars

    5cm³ Benedict's reagent was then added. The boiling tube was placed in the water bath for 8 minutes, then removed and cooled. The colour was noted. 2a, b, c The above procedures were repeated except that 0.1% sucrose was used instead of 0.1% Glucose.

  1. Investigation into reducing sugar content of a variety of soft drinks (not diet).

    A calibration curve can be prepared by plotting a graph of absorbance or transmittance against the various concentrations. * Range of soft drinks including (Fanta, Lilt, Ribena Sparks, Panda Lemonade, Sprite) The soft drinks of Fanta, Lilt and Ribena Spark were all fruit based therefore I chose them to see if fructose was present.

  2. Marked by a teacher

    Affect Of Varying Salt Concentration on Red Blood Cell Haemolysis

    4 star(s)

    Absorbance Readings % Mean (%) 1 2 3 0.0 14.0 18.0 12.0 15.0 0.1 22.0 18.0 19.0 20.0 0.3 15.0 10.0 13.0 13.0 0.5 46.0 45.0 54.0 48.0 0.7 75.0 69.0 66.0 70.0 0.9 89.0 80.0 75.0 81.0 1.0 88.0 82.0 87.0 86.0 As a result of preliminary test results

  1. Peer reviewed

    "An investigation into the Respiration of Carbohydrate Substrates by Yeast."

    5 star(s)

    cylinder was clamped in place, with the top resting on the beehive shelf, the hole being directly under it. 5. The yeast was placed in the preheated water-bath and the bung from the delivery tube was replaced. 6. The delivery tube was inserted into the hole in the side of the beehive shelf and the stop watch was started.

  2. Marked by a teacher

    Investigating how sugars are metabolised by yeast

    4 star(s)

    During alcoholic fermentation, yeast produces a group of enzymes (zymase complex) which breaks down sugars to carbon dioxide and ethanol. Sugars are groups of carbohydrates which are classified into monosaccharides and disaccharides. The following are the common characters of monosaccharides and disaccharides.

  1. Marked by a teacher

    Aim: To test for reducing sugars using glucose, sucrose and lactose to see which ...

    3 star(s)

    First test a sample for reducing sugars, to see if there are any present before hydrolysis. Then, using a separate sample, boil the test solution with dilute hydrochloric acid for a few minutes to hydrolyse the glycosidic bond.

  2. Marked by a teacher

    Investigate a factor which can affect the process of osmosis in a living plant ...

    4 star(s)

    The volume of the sucrose solution If the volume of solution does not cover the whole chip then this would affect the results, as osmosis will not be occurring over the largest area possible, which it should be. Make sure the dilutions add up to the same volume.

  • Over 180,000 essays
    written by students
  • Annotated by
    experienced teachers
  • Ideas and feedback to write
    your own great essays

Marked by a teacher

This essay has been marked by one of our great teachers. You can read the full teachers notes when you download the essay.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review on the essay page.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review under the essay preview on this page.

Do not show me this again

Are you in the right place?

Jump to Biology and see how teachers think you should prepare in: