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

Investigation into the Effect of Temperature on the rate of Respiration of Yeast

Extracts from this document...

Introduction

1 Sean Sandford11B Biology Coursework- Investigation into the Effect of Temperature On the Rate of Respiration of Yeast Preliminary Work For my preliminary work, I am working with 35ml of yeast. I think that this is the best volume to use as it is about 3/4 of a test tube full, and it allows for the yeasts expansion when heated. I am trying to find out the best range of temperatures to be used in finding out the respiration of the yeast, and I am also trying to find an equilibration time that can be used in the main experiment, as the time taken for the yeast to heat up to the desired temperature. Apparatus - One beaker - Two test tubes - Delivery tube with bung - Yeast (35ml) - Water - Stopwatch - Thermometer - 35ml syringe Method 1. A beaker was filled with water then heated to the desired temperature. 2. A test tube was then filled with 35ml of yeast and placed in the beaker of water. 3. The time taken for the yeast to heat up to the temperature of the water in the beaker was then measured using a stopwatch and thermometer. ...read more.

Middle

Prediction From the results of my preliminary work, I predict that between 20o and 40oC, the yeast enzymes will be respiring fastest because enzymes work best at room temperature. I also predict that as the temperature goes up, the respiration will get slower and slower because the enzymes will start to denature (the yeast enzymes stop working) at higher temperatures. This is shown in the graph on the next page: 4 Sean Sandford11B 40o is the optimum temperature because it is just the right temperature for the enzymes to be working at maximum rate. Yeast is an enzyme, which means that it is also a catalyst. Enzymes work using the 'lock and key' theory, where the 'key' fits into the active part of the enzyme (the 'lock') and the reaction takes place. The key then unlocks to form one or two more new substances and the enzyme is ready to bind with another of these substances. An enzyme can only bind with a substance that fits the shape of the active part of the enzyme, so, because the enzymes are sensitive to higher temperatures, the active site on the enzyme changes shape so much that binding can hardly take place. ...read more.

Conclusion

The key then unlocks to form one or two other substrates, and the enzyme is ready to bind again with one of these new substrates. An enzyme can only bind with a substrate that fits the shape of the active part of it, so, because the enzymes are sensitive to higher temperatures (in my graph any temperature below around 50oC) the active part of the enzyme changes shape so much that the binding can hardly take place. This is the denaturation, and it also means less respiration. As the temperature rises to 40oC, the yeast enzyme works at a faster and faster rate, because it is a catalyst and therefore speeds up reaction rate. This 'lock and key' theory is shown in the diagram below: 9 Sean Sandford 11B Analysis My conclusion does support my prediction to quite a large extent. The graphs both show that I predicted correctly the optimum temperature would be 40oC, and also that after this temperature, the enzymes would start to denature. At 40oC, the enzymes are working the fastest, colliding with the glucose molecules, and breaking them down to be used for respiration. The only difference between the prediction and conclusion is that I predicted that the enzymes would have completely denatured by 70oC, when in fact there was still some respiration. This shows that my conclusion supports my prediction to quite a large extent. ...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 Molecules & Cells 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 Molecules & Cells essays

  1. Marked by a teacher

    The Effect Of Temperature on the Respiration Of Yeast.

    5 star(s)

    At the end of glycolosis the product made, pyruvate still has a lot of chemical potential energy left over. When there is free oxygen available, some of this energy can be released via Krebs cycle and oxidative phosphorylation. If under anaerobic respiration, pyruvate gives off CO2, ethanal, which is then, reduced to ethanol.

  2. Marked by a teacher

    Investigating respiration of maggots

    5 star(s)

    This is the case for the manometer, which is connected to a control tube. When the invertebrates are placed in a water bath both the tubes are at the same temperature, and therefore the same pressure. Therefore the manometer fluid will not move away from the invertebrates, as there is an equal force to oppose this increase in pressure.

  1. The investigation to find the effect of glucose concentration on fermentation of yeast.

    Fermentation is the process of making alcohol. In fermentation the two important substances are the yeast and sugar in the form of glucose. The process turns glucose in to ethanol, alcohol, and carbon dioxide. It can be written as: Glucose ethanol + carbon dioxide C6H12O? [RM1](aq) 2C?H5OH (aq)

  2. The aim of this investigation is to find out how concentration of glucose affects ...

    reaction as fast as it can and increasing the substrate concentration past this point will cause no further increase in rate of reaction. The reaction has reached its maximum speed and this point is called Vmax. The graph below shows what I expect to obtain from my results: 4.

  1. Affect of sucrose concentration on the rate of respiration.

    I think this was the major advantage of using this source of information. The disadvantage of using this source of information was that the information had to be manually searched for which was time consuming. I also used the following website to research my investigation * Www.bbc.co.uk/education/asguru/biology * http://gened.emc.maricopa.edu/bio *

  2. The rate of respiration in yeast and how it is affected by temperature.

    The glucose will be measured out like the yeast with a pipette into a measuring cylinder. Fair test To produce a fair test I will need to repeat each part of the experiment three times to eliminate anonymous results. The indicator I am using is Bubbles of Carbon Dioxide that appear.

  1. Investigation into the Effect of Temperature on the Rate of Fermentation by Yeast.

    960 1 0 360 1 0 990 1 0 390 1 0 1020 1 0 420 1 0 1050 1 0 450 1 0 1080 1 0 480 1 0 1110 1 0 510 1 0 1140 1 0 540 1 0 1170 1 0 570 1 0 1200 1 0 600 1 0 Table 3.

  2. Experiment to Show the Respiration Rate in Yeast

    Carefully mix together the flour, sugar, and yeast. 3. Pour this mixture into a beaker and slowly add the water, a little at a time, whilst stirring thoroughly in between. 4. Stir the mixture with the glass rod till all lumps are gone and the mixture is consistently smooth.

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