• 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. Peer reviewed

    "An investigation into the Respiration of Carbohydrate Substrates by Yeast."

    5 star(s)

    Thirty seconds was timed then the beaker with the yeast/carbohydrate mix was swirled for 5 seconds to mix the yeast/carbohydrate. 8. This was repeated every thirty seconds for fifteen minutes, with readings being taken at three five minute intervals.

  2. Peer reviewed

    Effect of Caffeine on the Heart Rate of Daphnia

    3 star(s)

    meal (the gut may appear green if the individual has been feeding on algae). As a result they make excellent subjects for the microscope as one can observe the beating heart. The heart is at the top of the back, just behind the head, and the average heart rate is approximately 180 bpm under normal conditions.

  1. 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.

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

    All this was done at room temperature. Readings were taken every 30 seconds from the measuring cylinder, on the volume of gas that had been produced. Conclusions From Trials * It became apparent that 1g of yeast was not enough and after several trials it was found that 5g of yeast worked well.

  1. Rate of Respiration

    will be denatured and respiration will stop. pH Enzymes have an optimum pH at which they have the highest rates of reaction. The pH affects the charge of the amino acids at the active site (as amino acids are Zwitter ions) and this causes the structure of the active site to change the substrate can no longer bind to form an enzyme substrate complex.

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

    concentrations of the sucrose solutions can be tested at the same time. The sucrose solution will be added to the beaker first, and then the yeast is added to the beaker. The beakers should be labelled with the concentration of sucrose they have inside so the results don't get mixed up.

  1. Effect of Caffeine on the Heart Rate of Daphnia

    Caffeine is also an addictive substance and is associated with many withdrawal symptoms. Typical withdrawal symptoms include headache, fatigue and muscle pain. These symptoms can occur within 24 hours after the last dose of caffeine. This is because without caffeine, the blood vessels of the head to dilate, leading to

  2. Investigate the effect different concentrations of glucose in a yeast & Glucose solution has ...

    Heavy metals such as Zinc * Stirring * Volume of yeast + Concentration * Volume of glucose Some of these factors will be controlled while others will be changed, or measured. Underneath you will see a table of what will be done.

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