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

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

Extracts from this document...


Amanda Walters Investigating the effect of concentration of sugar on the respiration rate of yeast We did an investigation to find how different concentrations of sugar effect the respiration rate of yeast and which type of concentration works best. Respiration is not breathing in and out; it is the breakdown of glucose to make energy using oxygen. Every living cell in every living organism uses respiration to make energy all the time. Plants respire (as well as photosynthesise) to release energy for growth, active uptake, etc.... They can also respire anaerobically (without oxygen) to produce ethanol and carbon dioxide as by-products. This reaction is shown in the equation: Glucose Ethanol + Carbon Dioxide + Energy C6H12O6 2C2H5OH + 2CO2 Anaerobic respiration by yeast is generally called fermentation. Yeast is a living organism that produces enzymes. These enzymes break down glucose (by colliding with each other) to be able to respire anaerobically. I predict that the rate of fermentation will increase proportionally as the concentration of sugar increases but only up to a certain point were it will begin to decrease and eventually stop. ...read more.


� Once the first bubble appears out of the tube and into the water filled beaker, we start the stop clock and count the number of carbon dioxide bubbles appearing. We must wait for the first bubble to appear because the enzymes do not collide straight away with the glucose. We do this for one minute then do the experiment again with a different concentration of sugar. We did a preliminary experiment that helped me choose my method. Instead of finding the respiration rate by the number of bubbles we tried to find the volume of carbon dioxide being produced. We used the same apparatus but instead of leaving the end of the tube in the water beaker we placed it in a water-filled upside down beaker. When the bubbles came out of the tube the cylinder began filling with carbon dioxide. So instead of counting the number of bubbles we had to measure the difference between the starting volume of water and the end volume to see how much carbon dioxide had been used. This experiment resulted being very impractical, as the respiration rate was far too small to be able to detect with the measuring cylinder. ...read more.


The rate of fermentation was very slow and so the bubbles could not be miscounted. All things were kept constant for a fair test. We used the same apparatus through out all the experiment. I believe the results are inaccurate as the pattern is very vague and the range in the numbers of the repeats is very large. The average respiration rate results for the sugar concentrations of 3g and 5g did not follow the pattern of the rest of the results. They were only 2g out of place so I believe a minor mistake might have been made like a mistiming, miscounting of the bubbles, inaccurate concentration of sugar, etc.... The first reading of the respiration rate of the sugar concentration of 1g was very inaccurate. This was due to an early timing, before the first bubble appeared. If I were to repeat this experiment I would begin with a much lower sugar concentration as these results only showed the decrease of the respiration rate and not the increase. I would also try a range of more varied concentrations to see if this would produce a larger difference in the results, as the respiration rate results were very similar and close together (apart from the average result for the sugar concentration of 1g compared to the rest). ...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

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

    Plan for Anaerobic Respiration in Yeast

    4 star(s)

    This is because when the particles of the substrate are heated they begin to vibrate more and so have more kinetic energy, therefore they move around more and increase the likelihood that they will move into the active site of the enzyme.

  2. Experiment to investigate the effect of temperature on respiration in yeast.

    I think the yeast runs out because the glucose can no longer feed it or the other alternative is the glucose runs out because the yeast thrives on it which causes the yeast not to respirate and there for the process the ends.

  1. The effect temperature has on the rate of anaerobic respiration in yeast.

    sure there are is no air left in the measuring cylinder lift it half way out the water and then hold it there. Then as soon as you place the syringe under the measuring beaker start the stop clock. Stop the stop clock when there is 2.5ml of carbon dioxide in the measuring cylinder.

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

    The most volume of carbon dioxide will be collected within the set amount of time between these temperatures, indicating that the yeast cells will respire fastest between these temperatures. I predict that the rate of respiration in the yeast would start of at a low rate and as the temperature increased until 40�C, the rate of respiration would also increase.

  1. Investigation of the effect of glucose concentration on anaerobic respiration in yeast.

    This is because of the Lock and Key Theory. Enzymes basically work due to the 'lock and key' theory, where the substrate (the 'key') fits into the active site on the enzyme and they bind together, the reaction takes place and the substrate unlocks to form one or more new substances leaving the enzyme ready to perform the binding again.

  2. An Investigation into the Effect of Temperature on the Rate of Respiration in Yeast.

    Below is how the equipment was set when I set it up for the experiment of the yeast respiration experiment: - 2. Firstly you will have to measure the right amount of yeast solution in the measuring cylinder and for this one it will be 20cm�, you then will have

  1. An investigation of the factors that affect the rate of respiration in Yeast.

    This means that the amount of glucose and yeast must remain the same throughout the experiment. Another thing that may make the experiment unfair is the amount of the hydrogen carbonate solution this is because it will take a longer time for the indicator to gain the orange colouration it does when carbon dioxide is present.

  2. Investigating respiration in aged yeast

    test tube - Stir it well so the glucose dissolves completely - Put the test tube in a water bath in the conical flask - Cover the test tube with a rubber cork that is connected with a plastic tube - Put the plastic tube in a measurement cylinder of

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