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

Investigate one factor that affects the rate of respiration of yeast

Extracts from this document...

Introduction

Biology Coursework Investigate one factor that affects the rate of respiration of yeast Plan Aim: In my experiment, my aim is to find out any correlation between the rate of respiration of yeast and the concentration of glucose in the yeast. I shall do this by conducing an experiment which will involves a steady increment of glucose and for each increment, I will measure the temperature to see whether if it increases and the rate of increment. There are many factors (variables) that could affect this investigation such as the temperature the yeast respires at as at different temperatures the enzymes in yeast work faster or slower at breaking down the glucose. The amount of yeast will also have an effect on the results, if we are to use different amounts in each experiment it will form an unfair test. I must also make sure to leave all experiment undisturbed during the course of respiring, this means they cannot be stirred or let air get to them. I have chosen to investigate the affect the % concentration of glucose has on rate of respiration in yeast. I will use an experiment to determine whether the yeast's rate of respiration will increase, decrease or if it will stay constant even when the % concentration of glucose in it is varied. Prediction: I predict that the yeast's respiration rate of reaction should increase in speed as the % of glucose increases. ...read more.

Middle

and the amount of glucose with a measuring cylinder (precise to �0.5ml) Apparatus: Yeast, glucose solution (with different concentrations), boiling tube, 250ml beaker, gas syringe, boss, clamp, stand, boiling tube rack, electrical balance, 2x measuring cylinder, spatula, delivery tube with rubber bung, cotton wool Diagram: Method: 1. Firstly collect all apparatus and set up like the diagram on the previous page. 2. Pour the 10% yeast solution and measure 10ml using measuring cylinder. 3. Measure 10ml of glucose solution (2% - initial) using measuring cylinder. 4. Pour the 10ml of 10% yeast solution into a boiling tube. 5. Reset the gas syringe if needed (moving it back to 0 ml). 6. Pour some hot water (amount doesn't matter) into a beaker. 7. Use a thermometer and check the temperature. If it is less than 40oC, add more hot water, if it is more than 40oC, pour out some hot water or add more tap water. 8. Put the 10ml of glucose solution and mix well using glass rod for 10 seconds 9. Immediately connect it to the gas syringe. 10. Start the stop watch and wait for 2 minutes. 11. When 2 minutes is reached, stop the stopwatch and record results (the volume of gas produced) in a table. 12. Repeat step 2-8 but with different concentrations of glucose (2%, 4%, 6% and 8, 10% concentration). Pretest: I started off using 10% yeast solution and 10% glucose solution (10ml). ...read more.

Conclusion

Although the inaccuracies are very small, it can still affect a little to the ending result. I could use the measuring cylinders with 0.1ml markings to measure the volumes so it is more precise. However, I would like to obtain more results, using higher concentrations of glucose. This is because I did only up to 10% concentration of glucose solution, which is very low. Therefore, the graph drawn didn't represent a full picture of the experiment, which if did, might conflict with my prediction. Although all results up to 10% concentration of glucose did agree with my prediction, but that doesn't mean if the glucose concentration is 70% it will still agree with my prediction, which is what I want to understand fully and investigate about. On the other hand I didn't have enough time to do so many readings. So if there was an extension in time for me to obtain more results, I could most probably give a stronger evidence for my prediction or prove it wrong. Possible Extensions: 1. Investigate the best pH for the yeast enzymes to work the fastest rate in. 2. Investigate the best temperature the yeast enzymes work at the fastest rate in. 3. Investigate the rate of respiration of yeast when the variable is the concentration of yeast. 4. Investigate whether a change in concentration of glucose or a change in concentration of yeast will affect the respiration of yeast the most. ?? ?? ?? ?? Isaac Wong 11H 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 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

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

    Biology coursework planning - the effect of lead chloride on the growth of cress ...

    5 star(s)

    Heat the seeds in the oven for a further 6 hours. 17. After 6 hours, repeat steps 12, 13 and 15 again. If the seeds grown in a particular lead chloride concentration are found to have the same mass again, then this is the actual dry mass (biomass)

  2. To Investigate the Effect of Substrate Concentration On Yeast Respiration

    Note all the results in a table such as the one below. This gives the rate in cm3 of oxygen produced in the time of 5 minutes, this is because I am timing how much oxygen gas is given off in the space of 5 minutes for the various concentrations of Glucose.

  1. Rate of Respiration

    Dependent variable The dependant variable will be the volume of c02 produced during yeast respiration. Null hypothesis There is no difference between the volumes of CO2 produced by any of these substrates when respired by yeast under the experimental

  2. An investigation to see whether the concentration of Sucrose effects the amount of Carbon ...

    The experiment is a safe one. There is no real danger to the observer when participating in this experiment. The only variable in this experiment will be the concentration of the sucrose solution i.e. the amount of sugar; all the other conditions will remain constant.

  1. The Effect of Different Substrates on the Rate of Respiration on Yeast (Saccharomyces cerevisiae).

    Anaerobic respiration releases much less energy than aerobic respiration, only 210KJ compared to 2880KJ. In anaerobic conditions most energy remains locked in the ethanol. One problem is that alcohol is poisonous in large amounts. If the concentration of alcohol gets more than 14% it kills the yeast and the fermentation stops.

  2. The effect of substrate of yeast fermentation and its respiration rate

    Then measure 100cm� of water and transfer into that beaker and stir. Now there is 5% suspension of yeast. * Using a different measuring cylinder transfer 5cm� of glucose solution prepared into 3 different test tubes and transfer same amount of yeast solution into 3 different test tubes and label them A-C.

  1. Effect of Caffeine on the Heart Rate of Daphnia

    Too much solution on the slide will cause the Daphnia to move about vigorously and this affects the heart rate. * The experiment for each concentration of caffeine is repeated once to improve accuracy. * As temperature affects the heart rate of Daphnia, the microscope is turned off when not in use as the microscope light radiates heat.

  2. Rate of respiration in Yeast.

    Theory: Yeast is a single celled fungus. It feeds saprophytically (secreting enzymes from cells) the enzymes digest the food on which the yeast is living. The enzymes digest the food the yeast is living on (normally sugars such as Glucose and Sucrose) breaking down the large molecules into smaller ones.

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