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

AT1 practical assessment – yeast respiration

Extracts from this document...


27th September 2001 AT1 practical assessment - yeast respiration AIM => investigate one thing that will change the rate of yeast respiration. When yeast respires, it is anaerobic, so the equation for yeast respiration is: Glucose => ethanol + carbon dioxide + energy There are two things that could change the rate of this respiration. These are; * A change in concentration * A change in temperature Increasing the concentration of glucose increases the rate of respiration because, based on the collision theory, there will be more glucose particles to collide with the active site of the yeast enzymes. Increasing the temperature will increse the rate of respiration because the molecules will have more energy. This means they will be moving faster, and will collide with the active site of the enzymes more often and with more force. PRELIMINARY WORK => To help me decide which variable to investigate, and what measurements I would use, I did some preliminary research and experiments. I did three experiments. These were: A 'control' experiment, which was carried out at room temperature using; 25ml water 1g yeast 1.5g glucose This gave us 2ml of carbon dioxide over 4 minutes. ...read more.


This was to measure the carbon dioxide, by the displacement of the water, after 3 minutes. Once this had been recorded, I repeated the experiment three times to make it fair and ensure there were no inaccurate results. Then I increased the temperature in the water bath to 20(C, and did the experiment again. I continued to do this with the measurements going up in 10s, so I had 6 results ranging from 10 C to 60 C. I made the experiment safer by using a kettle rather than a bunsen to heat water, and by wearing safety goggles. PREDICTION => I predict that increasing the temperature will increase the rate of reaction. The reaction will produce approximately 3ml of extra carbon dioxide for every 10 C the temperature is increased by. I am basing this prediction on two things, the collision theory, and my preliminary work. The collision theory, as mentioned earlier, says that increasing the temperature will speed up the respiration, because the glucose particles will have more energy, and they will collide with the active site of the yeast particles with greater frequency and force. I think that the amount of carbon dioxide will increase in 3ml amounts because of the results of my preliminary work. ...read more.


As the respiration took place, more glucose was being used up, and so the concentration was decreasing. If I were to do this experiment again, I would change the following things: * Use a more accurate way to measure the temperature of the water bath, and keep it constant. * Use a more accurate time measurement. * Use a fresh yeast, glucose and water mixture for each experiment. However, this was not possible because we did not have enough mixture for the whole group to do this. The only problem with this would have been making sure we kept the whole batch of yeast stirred up, so the yeast did not settle. These measures would ensure I got more accurate results. To extend the investigation, I could investigate how the concentration affects the rate of respiration as well. This would enable me to compare the two variables and decide which has the greatest effect. I had an anomalous (wrong or unusual) result. I pointed this out on my graph, by circling it in blue. I think this was caused by some of the inaccuracies mentioned above, because it is not a largely wrong result, just outside of the curve. My investigation has clearly showed that temperature affects the rate of respiration. ...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 Humans 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 Humans as Organisms essays

  1. Marked by a teacher

    The effect of different sugar substrates on the rate of yeast respiration

    4 star(s)

    This will be done for accuracy. * pH- buffer tablets will be used to maintain the pH of the water used to make the solution. The buffer tablets that I will use will be pH 6 and this is ideal as it is the optimum pH for the yeast.

  2. Marked by a teacher

    An investigation into the effect of temperature on the rate of respiration in yeast

    4 star(s)

    Each time I use a new temperature, I will use a new set of yeast, glucose, paraffin and diazine green. I will then repeat the experiment, making sure each time that anaerobic respiration has started (i.e. mixture is pink). These are the temperatures I plan to use: 20 oC 30

  1. Marked by a teacher

    How Does Temperature Affect the Rate of Respiration of Yeast?

    3 star(s)

    Faster particles will bring about more particle collisions and so the reaction will take lace faster. Enzymes are sensitive to temperature changes up until a certain temperature and will increase in their activity also. The reactions that take place in the enzymes will be quicker and so will create more of their products.

  2. An experiment to investigate the rate of anaerobic respiration of yeast in various respiratory ...

    * In order to generate results from the experiment, I will note down the distance moved along the capillary tube by the manometer fluid from a starting point at each of the 3 minute time intervals. Thus the data collected will be quantitative data (refer to 5th bullet point in justification).

  1. Experiment to Investigate Factors Affecting the Rate of Respiration in Yeast

    If I had realised this mistake sooner, then I would have rectified it by repeating this experiment again. I followed my safety rules as well, and this meant that I didn't cut or burn myself. I followed my Plan and Method, and these ensured that my experiments ran smoothly and efficiently, and the minimum of time was wasted.

  2. Diabetes Type 1 and 2

    But even if there aren't any symptoms, you should still get treatment to reduce the risk of developing complications. The treatment for type 2 diabetes is most importantly the change in lifestyle. Eat a healthy and balanced diet. Diabetic foods still raise blood glucose levels, contain just as much fat and calories and are usually more expensive than non-diabetic foods.

  1. An Investigation into how the anaerobic respiration of glucose and yeast is effected by ...

    It is also predicted that after 40�c, the rate of anaerobic respiration (the amount of carbon dioxide released) will go down. SCIENTIFIC KNOWLEDGE All substrates need an enzyme to break them down into simpler forms. In the case of this experiment, the substrate is glucose and the enzyme is zymase (it is carried by yeast).

  2. Biology 1 Edexcel Science Overview Revision Notes.

    inherits two copies of the recessive mutation then the individual will be affected by the genetic disorder. The risk of someone inheriting a particular disorder can be predicted using pedigree analysis. This looks at the disorder?s inheritance pattern and predicts the risk for future generations.

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