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

Does temperature have an effect on the activity of dehydrogenase enzymes in yeast cells?

Extracts from this document...

Introduction

The Effect Of Temperature On Enzyme Activity Hypothesis: Does temperature have an effect on the activity of dehydrogenase enzymes in yeast cells? Aim: The aim of this experiment is to show the relationship between temperature and the rate of activity of dehydrogenase enzymes in two different yeast types ('Bakers' and 'Brewers'). We can then compare the results of the two different types of yeast to see which type is more affected by changes in temperature. Triphenyl tetrazolium chloride (TTC) is an artificial hydrogen acceptor, or redox indicator. When oxidised, TTC is colourless, but when it is reduced, TTC will form red, insoluble compounds called formazans. This colour change therefore shows the presence of active dehydrogenase enzymes in yeast cells. The temperature of the TTC solution and yeast suspension will affect the rate at which this colour change occurs, which in turn will show how the activity of dehydrogenase enzymes in different yeast cells changes. Background Theory: Enzymes are tertiary protein structures made up of a single polypeptide chain. The polypeptide chain is folded into a precise shape, giving enzymes their specificity. Enzymes maintain this permanent shape by a range of bonds holding them together, including disulphide bridges, ionic bonds and hydrogen bonds. Enzymes are specific to the reactions that they catalyse, so the active site on an enzyme has a particular shape into which a specific substrate will fit. ...read more.

Middle

The rate of reaction will rapidly decrease as the enzymes are given so much kinetic energy, they start to change shape so the substrates don't fit in exactly anymore. They change shape because the bonding becomes irreversibly changed so the active site is permanently damaged. The experiment will eventually reach a temperature where the enzymes will be totally denatured and will have completely changed shape, so the rate of reaction will be zero. Outline Method: This experiment is designed to show the relationship between temperature and the rate of activity of dehydrogenase enzymes in different yeast cells. Triphenyl tetrazolium chloride (TTC) is an artificial hydrogen acceptor, or redox indicator. When oxidised, TTC is colourless, but when it is reduced, TTC will form red, insoluble compounds called formazans. This colour change shows the presence of active dehydrogenase enzymes in yeast cells. The temperature of the TTC solution and yeast suspension will affect the rate at which this colour change occurs, which in turn will show how the activity of dehydrogenase enzymes in different yeast cells changes. What am I going to change? Why? INPUT VARIABLE The temperature of the TTC solution and yeast suspension. The yeast to be used ('bakers' and 'brewers') I am going to change the temperature to determine what sort of effect it has on the activity of dehydrogenase enzymes in yeast cells. By using two different types of yeast, I can see how the rate of reaction differs with varying temperature, between the two different types of yeast. ...read more.

Conclusion

At extreme pH values the enzyme will become denatured, and the shape of the protein molecules are altered as the hydrogen bonds and sulphur bridges are broken or formed. I can control this by using the same pH of enzyme and substrate from the same bottles of their solutions, and double check by using universal indicator paper. ? Volume - I must keep the volume of the yeast suspension and the TTC solution the same. If I put a large volume of TTC into a test tube and react it with the yeast at a set temperature, the rate of this reaction would be faster than if I put a small volume of TTC into a test tube and reacted it with the same yeast at the same temperature. To control this I will measure the volume (in cm3) using a measuring cylinder of each solution. Reliable results: Range of temperatures (oC): 10 oC, 20 oC, 30 oC, 40 oC and 50 oC. (Measured with thermometer) Types of yeast: 'Bakers' and 'Brewers'. Concentration of enzyme and substrate (mol):Kept the same throughout. Recorded at each set temperature. Volume of enzyme and substrate (cm3): Kept the same throughout. Recorded at each set temperature. (Measured with measuring cylinder) pH of enzyme and substrate: Kept the same throughout. Recorded at each set temperature. Number of repetitions of each yeast at the set temperature: 3 Risk Assessment and Ethical Considerations: See 'Material Data Safety Sheet' for TTC. Always wear safety goggles to prevent solutions splashing into eyes. ...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 Molecules & Cells 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 AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    The Effect Of Temperature on the Respiration Of Yeast.

    5 star(s)

    disulphide bonds, the tertiary structure then collapses and the shape of the active site changes, the substrate molecule cannot fit and the substrate can no longer be catalysed. This is called denaturation. I predict this to happen at about 40oC, as this is the optimum temperature at which the dehydrogenase enzyme works.

  2. Marked by a teacher

    Investigate the effect of temperature on dehydrogenase activity in yeast. At which temperature is ...

    4 star(s)

    I will be aiming to find out the rate of the reaction and see the changes in temperature over time using this information. Hypothesis Enzymes are chemicals that increase in activity as the temperature increases. Once the enzymes reach a specific temperature, their active sites become denatured.

  1. Investigating the effect of temperature on the activity of free and immobilised enzymes.

    This graph doesn't apply for all enzymes as enzymes in the stomach have a low optimum pH and so are suited to the acidic conditions of the hydrochloric acid in the stomach. The bell shape either moves to the left or the right depending on the optimum pH for the enzyme.

  2. An experiment to find of the isotonic point of root vegetables cells in contents ...

    This is what caused the carrot cell to decrease in length and width at this concentration. The beetroot was placed in sucrose solutions with molarity of 0.6, 0.65, 0.7, 0.75 and 0.8. The beetroot placed in sucrose solution with molarity of 0.6 and 0.65 had an increase in mass, width

  1. An Investigation Into the Effect of Substrate Concentration On the Rate of Enzyme Activity.

    The immobilised catalase enzyme had a different temperature at which the peak occurred from the non-immobilised catalase enzyme. This could be because the immobilised enzymes are protected substantially more than the non-immobilised enzymes. The sodium alginate also holds the tertiary structure of the catalase in place and makes the enzyme more stable.

  2. WHAT EFFECT DOES SUBSTRATE HAVE ON THE RATE OF RESPIRATION IN SACCHAROMYCES CEREVISIAE?

    Stir the solution thoroughly using a stirring rod. This is how the buffer solution is prepared. It works effectively if dissolved in 1 litre and so that is what I shall do too. The buffer solution is needed in order to dissolve both the saccharomyces cerevisiae and substrate into.

  1. Investigation into the Effect of Temperature on the Rate of Fermentation by Yeast.

    19 15 720 57 53 120 24 20 750 57 53 150 40 36 780 57 53 180 47 43 810 57 53 210 52 48 840 57 53 240 55 51 870 57 53 270 56 52 900 57 53 300 57 53 930 57 53 330 57 53

  2. Trypsin. Hypothesis: - I hypothesize that as the temperature increases the rate of enzyme ...

    Thus too much heat can cause the rate of an enzyme-catalysed reaction to decrease because the enzyme becomes denatured and inactive due to high temperature. Optimum temperature is the temperature at which the enzyme works the best and the rate of the reaction is the fastest.

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