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

Biology investigation to investigate how selected variable affects the rate of fermentation in yeast.

Extracts from this document...


Biology investigation to investigate how selected variable affects the rate of fermentation in yeast Planning I think that the easiest way to measure the rate of fermentation in yeast is to measure a waste product of respiration. When the yeast is unable to respire aerobically it respires anaerobically producing alcohol and carbon dioxide. I could measure either of these two things to measure the rate of reaction. To measure the volume carbon dioxide is easier. I will do this by counting the number of bubbles of carbon dioxide through a wine trap with water in it. This gives a good indication of how fast fermentation is occurring. I predict that as the temperature rises so will the rate of reaction in the yeast and therefore the volume of carbon dioxide produced. However when temperatures exceed 40�C the rate of reaction will start to decline and beyond 70�C the reaction will cease and if temperatures are significantly below 40�C (20�C) there will be very little or no reaction. I am of this opinion because of the way enzymes are affected by temperature and because yeast contains enzymes. I know that enzymes have an optimum working temperature of about 40�C and that below this they fail to work effectively and above it they become denatured and fail to work. ...read more.


Step 2 When the water has heated to the correct temperature (15�C above chosen temperature) pour 50cm� into the 75cm� tripour and 100cm� into the water bath. Measure the temperature, which should have fallen to about 7�C above the required temperature. Place the remaining water back onto the heat and leave with the Bunsen burner on a low heat setting. Step 3 Add the sugar, weighed previously, to the water that is in the 75cm� tripour. Using the stirring rod, stir the solution until all of the sugar has been fully dissolved. Then pour this solution into the fermentation vessel. Step 4 Using the funnel add the yeast to the fermentation vessel and replace bung. Next add 2ml of water to wine trap. Then with finger on the bung shake the vessel vigorously for about 40-60 seconds. After this, remove bung and as quickly as possible replace with wine trap. Immediately immerse the fermentation vessel complete with wine trap into the water bath. Step 5 Using the thermometer check that the temperature of the water bath is exactly as desired. If it is too low then add hot water from the large beaker being heated by the Bunsen burner, using the pipette dropper. If it is too high then add cold water. ...read more.


The results from repeat reading are slightly different in most cases but never by anything greater than 4. This does however show that the results could have been better. A 3rd repeat of the experiment would have been preferred enabling me to produce a more accurate average. Unfortunately I didn't have time. There was one difficulty in counting the numbers of bubbles. As mentioned earlier the heated water which was added to the water bath caused the top of the fermentation vessel to heat rapidly and the air inside to expand forcing air through the wine trap producing bubbles. These had to be distinguished from carbon dioxide bubbles which were to be counted. Had I had more advanced equipment I would have liked to use a thermostat and some means of electronic heater to control the temperature of the water bath and produce more accurate readings. I had biased my suggested temperature values to be more concentrated around the 40�C mark but I think that it may be worth doing more in this range perhaps trying to do it at 1�C intervals, from say 35�C - 45�C. This would be difficult however and would require more advanced equipment such as a thermostat and electric heater immersed within the water bath. With this level of accuracy it may be worth then using a gas measuring syringe to measure accurately the volume of carbon dioxide produced. ?? ?? ?? ?? 1 Lewis Buckley 10A (T/A) ...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)

A really good report on the effect of temperature on rate of fermentation. To improve on this I thought you could have included more detail on the theory side of enzymes, how they work and what happens when they become denatured. I think it would also have benefitted from an explanation of what fermentation is.
The analysis was good but do not forget to use data from the results section to support what you are saying.
Method very good.

Marked by teacher Jon Borrell 08/01/2013

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)

    Safety Precautions: Although there are limited safety precautions and risks involved with this investigation, I need to make sure that I am still careful with all my experiments given that I am using both water (in order to wet the cotton wool)

  2. Factor affecting the rate of fermentation.

    Apparatus: * Flasks * Boiling tubes * Cylinders * Cotton * Rubber Corks * Rubber tubes * Water Bath * Clam and Stand * Short glass tube Materials: * Warm Water * Yeast * Glucose solution * NaHCO3 solution Safety: * Clear out the surrounding (around 1 meter).

  1. Investigating the Factors Affecting Respiration in Yeast.

    If there is more yeast than other factors then it may influence the result rate to increase. If there is more sugar than the other factors it may also cause the experiment to speed up and create more energy from the glucose than it is meant to.

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

    I also predicted that the increase in mass would be the most out of all solutions however I also said that the change in mass would not be the most out of all solutions. I knew that this prediction would be correct because the high concentration of water and almost

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

    The respiration goes down because more of the yeast is dying as the sugar molecules are much larger and so enter the yeast at a much slower rate than the water in the yeast diffuses out. Water actually moves both ways but as not all the sugar will have dissolved

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

    If the substrate molecule does not have the correct configuration (shape) to fit into the active site (i.e. the key does not fit into the lock), then no reaction can take place. In general, the rate of an enzyme-controlled reaction is doubled with a rise of 10�C over a range from 0�C - 40�C.

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

    to futher detail and invertigatiomn In order to keep the experiment a fair one I will carry out the following: * Keep all measurements the same as the previous experiment/s. * Time limit the same. * Record all results the same also.

  2. Experiment to Investigate the Effect of Temperature on the Rate of Photosynthesis in Elodea.

    light-independent process in which carbon dioxide combines with RuBP (ribulose bisphosphate), to give two molecules of GP (glycerate 3-phosphate). This fixation is controlled by the enzyme RuBisCo. This stage is said to be thermochemical because the reaction is directly affected by temperature.

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