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

Yeast Coursework

Extracts from this document...


Biology Coursework: Respiration in Yeast Planning Aim The goal of this experiment is to discover how varying the temperature, of a solution of yeast and sucrose, will affect the amount of carbon dioxide produced during a set time period. After I have completed this experiment and obtained enough data, I will analyse and discuss it, and then I will evaluate it. For this experiment, my independent variable will be the temperature, which I will change by adding warm water to it. My dependent variable will be the amount of carbon dioxide given off. My controlled variable will be the amount of sucrose and yeast there is in the solution, and also the time the experiment will be running for, as these are the only factors that can be varied to produce different amounts of CO2. Background Knowledge This experiment involves enzymes, which are biological catalysts. All the chemical reactions in a living organism are collectively known as the metabolism. Anabolic reactions normally need an input of energy, to build up large molecules from smaller ones. Catabolic reactions often release energy when breaking down large molecules into smaller ones. An example of anabolism is the condensation of glucose molecules, which happens in liver cells and skeletal muscle. ...read more.


During this period, I will prepare for the next temperature, and prepare the yeast and sucrose as above. When the first test is over I will increase the temperature by adding some warm water to the cup from the kettle, to get it to he right temperature. In order to keep the temperature the same throughout the experiment, I will pour some of the hot water into a separate cup, so that I can pour some into the cup if the temperature should fall below a certain point. This should help to keep it a fair test. Safety is always a priority, and it is no different in this case. In this experiment there are no hazards to be wary about, other than the water from the kettle. To stay safe while pouring it, I will place the cup on the desk, and pour the water in slowly. I will also keep my bag out of the classroom, and the chairs under the desks. Prediction I predict that as the temperature is raised, then so will the rate of respiration. I believe that this will continue to happen up to an optimum temperature, at which the active sites of the enzymes will begin to denature. ...read more.


The quality of my evidence is, overall, accurate and also reliable. This is because they follow scientific theory like the 'lock and key hypothesis' and the Collision Theory. It followed my prediction that was based on scientific theory. The results follow the expected pattern, which has reaches optimum temperature and then, when it starts to denature, the respiration rate falls. There was one set of anomalous results obtained in this experiment. This was when the temperature was at 30ºC. I believe these results to be anomalous as the do not follow scientific theory. At this temperature, the rate of respiration does not increase from the first set of results, which were at 20ºC. According to the lock and key hypothesis, a rise in temperature should increase the rate of respiration. This is not the case with this set of results. The rest of the results do, however, follow theory. On the next page there is a table commenting on how the experiment could be improved in order to gain more accurate results, and minimise the risk of anomalies. Possible sources of error/inaccuracy Ways to improve The collecting cylinder. Use one with smaller measurements. Solution not the right temperature. Leave time for the yeast to heat up before adding the sucrose and starting the experiment. The data I've collected is sufficient to draw the conclusion that my prediction was correct. ?? ?? ?? ?? David Hart Biology Coursework: Respiration of yeast -1- ...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 Energy, Respiration & the Environment 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 Energy, Respiration & the Environment essays

  1. Marked by a teacher

    effect of temperature on the rate of respiration in yeast

    5 star(s)

    Yeasts multiply as single cells that divide by budding or direct division and they may grow as simple irregular filaments. These are egged shape that can only be seen by microscope. Yeast cells also digest various sugars like sucrose, fructose and glucose.

  2. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    14.5 35.5 12:8 50.0 49.5 48.2 46.1 44.8 40.9 37.5 32.1 27.5 23.8 18.7 31.3 10:10 35.0 34.5 32.5 31.3 28.2 25.6 21.0 16.8 13.2 9.5 5.2 29.8 8:12 50.0 49.3 48.5 47.3 46.3 45.0 44.1 42.9 40.7 39.1 36.9 13.1 5:15 35.0 35.0 34.7 33.6 31.5 30.0 28.7 27.4

  1. Marked by a teacher

    Effect of Anaerobic Respiration On Yeast

    5 star(s)

    time then inaccurate readings for displace water could be made Same person fills the burette each time so measurments taken from the same place Equipment: Equipment Use Precision Burette Measure the water displaced 0.1ml Water Reservior Allow for burtette to be suspended in water NA Yeast Suspension To be experimented

  2. Marked by a teacher

    'An investigation into the ability of two strains of the yeast Saccharomyces cerevisiae to ...

    4 star(s)

    These nutrients comprise 0.50g of ammonium phosphate and 0.50g of ammonium sulphate. 200cm3 of distilled water should now be measured out with the use of a measuring cylinder. With the use of a glass rod, the aqueous solutions should be stirred until the sugars and the culture nutrients have been dissolved and dispersed.

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    The body neutralises the acidic conditions produced by stomach to this pH by secreting bile into the duodenum of the small intestine which contain hydrogencarbonate ions. This is important for this investigation as to maintain lipases optimum working conditions not only do we have to monitor and control the temperature

  2. out how different concentrations of the enzyme pectinase affect the degradation of the substrate ...

    I believe that as the concentration of pectinase increases so will with the yield of apple juice produced until a point is reached where the pectin concentration and the pectinase concentration equal each other and no extra pectins will be degraded hence no extra apple juice will be produced.

  1. Investigate the effect of bile salt concentration on the digestion of milk by the ...

    However, after a certain point, increasing the substrate concentration no longer increases the velocity of the reaction. This is because all the enzymes present have already formed the enzyme-substrate complex and so in essence there are no free active sites available for the catalysis of the increased substrate.

  2. An investigation into the effects of temperature on the rate of anaerobic respiration of ...

    Glucose --> ethanol + carbon dioxide +energy C6H12O6 + 6O2--> 6CO2 + 6H2O The Kinetic theory states that, with an increase in temperature, the rate of reactions will increase. This is due to the increase of speed of the particles, brought about by the extra energy given to them by heat.

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