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

Reducing and non-reducing sugars tests.

Extracts from this document...


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. ...read more.


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) ...read more.


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 ...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)

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...
  • 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

    Affect Of Varying Salt Concentration on Red Blood Cell Haemolysis

    4 star(s)

    cells Note: Allow a 180second gap between adding blood to each test tube, this is so there is sufficient time at the end of the 1,800 seconds to transfer sample into the cuvette and take a colorimetric reading. If a gap is not left the blood could be left in

  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

    Mr Chips: Investigation to find an isotonic solution for potatoes

    4 star(s)

    With an increase in concentration a decrease in mass was shown for the chips, proving the solutions to be hypertonic. Percentage concentrations over 2.5 are most certainly too strong to be anywhere close to an isotonic solution. On this basis, the decision to have a narrower range of concentrations was

  2. Marked by a teacher

    Osmosis. Aim: To find the molarity of potato tubers cell sap. BIOLOGICAL ...

    4 star(s)

    its contents, osmosis wouldn't be taking place and there would be no net movement of water as the number of free molecules are same on either side of the semi-permeable membrane. Factors affecting Rate of Osmosis The rate of osmosis is often varied due to different factors.

  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. Peer reviewed

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

    5 star(s)

    The beehive shelf was used to make sure all the gas was directed into the measuring cylinder. However, during the pilot, it was found that gas bubbles collected underneath it and were therefore not counted in the experiment. We rectified this point by using a rubber tube attached to the delivery tube to direct the bubbles into the measuring cylinder.

  1. AS biology coursework on enzymes

    substrate molecules have to wait a long time in order for them to catch a free enzyme which is available. EVALUATION In overall I think my investigation on finding the relationship between increasing substrate concentration and keeping enzyme concentration constant was successful.

  2. The mechanism of Negative feedback.

    ((Diagram showing simple negative feedback system) They all have an output, an example being such as the internal factor such as blood temperature. The output is controlled, and a set point (also called normal or reference point). In physiological process, the set point is usually determined genetically and is the optimal physiological state for the output.

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