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

Use of a redox indicator to show dehydrogenase activity.

Extracts from this document...

Introduction

Use of a redox indicator to show dehydrogenase activity Introduction: Triphenyl tetrazolium chloride (TTC) is an example of an artificial hydrogen acceptor, or redox indicator. TTC is colourless when oxidised, but forms red, insoluble compounds called formazans when reduced. TTC can therefore be used to show the presence of active dehydrogenase enzymes by a colour change. This experiment investigates the effect of temperature on the activity of dehydrogenases in yeast cells. Materials: * Actively respiring yeast suspension. This should be prepared by adding 100g of dried yeast to 1dm3 of water and mixing in 50g glucose. This mixture should be allowed to stand in a large beaker for about 2 hours before the experiment. * Triphenyl tetrazolium chloride solution, 0.5% * Distilled water * Test tubes and rack * Graduated pipettes, or syringes * Glass rods * Crushed ice * Beakers or water baths * Thermometer * Stopwatch Method: 1. Set up water bath at 30?C. 2. Pipette 10cm3 of yeast suspension into one test tube and 1cm3 of TTC solution into another test tube and stand them both in the water bath. ...read more.

Middle

The effect of a 10?C rise in temperature on the rate of a reaction can be expressed as the Q10 value. This is a ratio of the rate of a reaction between two temperatures. These are the Q10 values for the temperatures used in this experiment. Between the range 20?C and 30?C = 0.002176 ? 0.001147 = 1.897 Between the range 30?C and 40?C = 0.003205 ? 0.002176 = 1.473 Between the range 40?C and 50?C = 0.004782 ? 0.003205 = 1.492 Between the range 50?C and 60?C = 0.006359 ? 0.004782 = 1.330 Between the range 60?C and 70?C = 0.007937 ? 0.006359 = 1.248 Between the range 70?C and 80?C = 0.007622 ? 0.007937 = 0.960 Between the range 80?C and 90?C = 0.007308 ? 0.007622 = 0.959 Between the range 90?C and 100?C = 0.006993 ? 0.007308 = 0.957 One source of error in this experiment was that not all the yeast suspension was always transferred into the test tube of TTC solution. This meant that different amounts of yeast suspension could have been actually used for each of the temperatures. ...read more.

Conclusion

The overall accuracy of the experiment could have been improved if the whole experiment was repeated two or three times and an average for each temperature taken. In organic molecules oxidation involves the removal of both electrons and protons. This process is called dehydrogenation. Dehydrogenases are enzymes that catalyse these reactions. In cell respiration, dehydrogenases are used in the first part of the breakdown of glucose (glycolysis). The two trioses produced after the splitting of fructose-1,6-biphosphate undergo dehydrogenation. The hydrogen atoms produced by this reaction are taken up by NAD+ to from NADH + H+. The electrons then pass along a series of electron carriers, making up the electron transport system. This electron chain then results in ATP synthesis, which is of course the point of respiration. The role of dehydrogenases is also seen in the Krebs cycle. Four of the steps in the Krebs cycle involve the removal of pairs of hydrogen atoms, which are catalysed by NADH dehydrogenase or succinate dehydrogenase. In the same way, the NADH + H+ goes on to the synthesis of ATP from ADP and Pi. Neal Desai Mr. Cooksey U6AA Biology ...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

Here's what a teacher thought of this essay

4 star(s)

****
Good biochemical knowledge demonstrated but a little more attention to detail is needed for a 5 star rating. Some discussion of the effects of temperature on enzyme activity would be relevant and helpful.

Marked by teacher Adam Roberts 18/07/2013

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 GCSE Green Plants as Organisms essays

  1. Peer reviewed

    An Investigation into the Effects that Different Light Intensities have on the Speed of ...

    5 star(s)

    After having completed the recording at each distance, the footage was rewound until the first readings at 100cm came on the screen. A sheet of acetate was placed on the television screen and secured with blue tack so that it would not slip out of place, 'play' was pressed on

  2. Factor affecting the rate of fermentation.

    put the boiling tubes into warm water (41?), too let the yeast work more efficiently. And we put all of the boiling tubes into the same water bath, to ensure that all the boiling tubes are keeping in the same environment.

  1. Investigating the Factors Affecting Respiration in Yeast.

    Independent and Dependent Variable The independent variable (the factor that I change and is my input) is temperature. My dependent variable (the factor over which I have no direct influence and is the output) will be the rate of carbon dioxide production.

  2. Determine the water potential of potato tuber cell with the varying affect of solute ...

    Table 1: showing the initial results of the experiment Molarity of solution (M) Initial mass of cylinder (g) Final mass of cylinder (g) Change in mass (g) % change in mass Distilled H2O 0.00 2.51 2.69 +0.18 7.17 Sucrose 0.20 2.52 2.63 +0.11 4.36 Sucrose 0.40 2.61 2.69 +0.08 3.06

  1. What is the effect on the rate of respiration of yeast cells with glucose ...

    to products. Enzymes are very specific as they can only catalyse a reaction in which the substrate molecule has a complementary shape to that of its active site. The substrate molecules that react together on the active site are likened to a 'key' and the active site to a 'lock'.

  2. Investigating the effect of concentration of sugar on the respiration rate of yeast

    This will then not be a fair test, as the reactions will have begun at different temperatures. � Keep the amount of yeast used in the test constant so there is the same amount of enzymes working each time. More enzymes would cause more collisions with the glucose and so a higher respiration rate.

  1. The relationship between flow rate and temperature difference

    and then pass the water from the top down to the bottom, this was based on the idea of solar panels. Using light bulbs placed around it to heat it. But this setup would have required an extreme amount of work due to the fact * The radiator was really

  2. Find out the effect of temperature on the bounciness of a ping-pong ball.

    Repeat Step 4 again once more and note the results. 6. Then take another beaker and again half fill it with water. Then heat this water until 75 degrees Celsius and place the ball again within the water and repeat the previous steps like done for 45 degrees Celsius.

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