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

Comparing the respiratory rate of yeast with different sugars.

Extracts from this document...

Introduction

Comparing the respiratory rate of yeast with different sugars Situation "A baker used uses sugars to make his bread dough 'rise'. He wanted to find out which sugar, of a number of sugars would give the best results" Introduction The raising agent within the dough is yeast, and this along with numerous sugars will be the focus of this investigation. The reason the yeast is a raising agent is because of fermentation. When flour is mixed with water, sugar and yeast, the yeast feed on the sugar. As the yeast release carbon dioxide and alcohol, the gas becomes trapped as bubbles in the dough, causing it to rise. Yeast is a unicellular fungus that has the ability to respire both aerobically and anearobically. Yet in order to produce carbon dioxide and ethanol it must respire anaerobically. This is one of the first facts about this investigation; in order for the bread to rise the yeast is produce carbon dioxide and respiring anaerobically. Respiration itself consists of a number of 'redox' reactions in which certain substrates are oxidised to become 'carbon dioxide' and 'oxygen' is reduced to water. ...read more.

Middle

The higher the difference in the structure of the sugar the less likely it is to match with the active sites in the yeast. I believe that the most suited from the disaccharide's will be maltose as it is formed from two molecules of glucose which can be split apart and then used. Fructose will be slower than maltose as it is only formed from one polymer of glucose. Plan I will make an active solution of yeast (that is a dry mass of yeast combined with de-ionised water) to eliminate and factors that could produce anomalous data. This I will then add 25cm3 of this solution to 25cm3 of a sugar solution via a 60cm3 syringe. The sugar solution of each of the 5 sugars will be 0.25M in strength, this has be shown to be the optimum concentration, for higher than this level can lead to detrimental osmotic problems. I will then empty the syringe of excess air and attach it to a 300mm capillary tube held within a clamp stand. ...read more.

Conclusion

The control experiment will consist of using the yeast solution on its own and measuring the respiratory rate, this will show that it is the sugar that has an effect on the respiratory rate of yeast and no other factor. The dependant variable in this experiment is the amount of CO2 produced. This will be obtained by dividing the time the solution takes to reach the mark on the capillary tube, by the distance it travelled to that mark. This will give the level of Co2 production per second. This measurement will be given in Co2/s in relation to the amount of yeast. This data , once collected will be logged in a data table and then present in suitable graphs and charts to show trends and identify anomalies. Apparatus * 60cm3 syringe. * Capillary tube. * Beaker. * Active yeast solution. * 5 sugar solutions of 0.25M (glucose, fructose, maltose, sucrose, lactose). * Stop watch. * Clamp stand. * Chinagraph pencil. Al the apparatus I intend to use is very low risk , and no special precautions will be needed, such as gloves or goggles. The 2 solutions have minimal risk if they came into contact with ones skin there could be possible irritation. Human biology Hugo Metcalfe 20513 ...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)

    In yeast the end products of Glycolysis is carbon dioxide and pyruvic acid which is then converted into ethanol. Although yeast can survive during anaerobic respiration, it does not grow and multiply as it would during aerobic respiration. Anaerobic respiration releases much less energy than aerobic respiration.

  2. Marked by a teacher

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

    4 star(s)

    Also I will only use 5cm of the yeast mixture and 5cm of the yeast mixture so that the mixture doesn't bubble over. I am going to also use 6 drops of paraffin so there is no way that oxygen can get in and trigger aerobic respiration.

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

    Yeasts are well known for the making of bread and wine. Yeast has to make energy, stored as ATP to carry out all cellular functions. To do this they can respire both aerobically when there is plenty of oxygen, but where oxygen is short, they respire anaerobically.

  2. Should the cloning of humans be allowed?

    The author also holds post doctorate training in genetics, which means that she is relatively experienced in the field. As well as this, she is an assistant research professor in the Department of fisheries and wildlife at Oregon state university where she conducts research like using genetics to compare the evolution of tropical and temperate birds.

  1. Cardiovascular and Respiratory Systems

    It is a pale yellow fluid made mainly from water and a small amount of protein. * Red blood cells: these are the most numerous cells in the blood. They are disc shaped with a depression in the centre at each side.

  2. Investigating the effect of temperature on yeast respiration.

    These temperatures will be 0�C, 20�C, 35�C, 40�C, 50�C, 60�C, 80�C. I will measure it across these temperatures because I feel that these are a good temperature range and they include some upper high temperatures and also some lower temperatures and collectively they provide a large temperature range.

  1. Should you vaccinate using the HPV vaccine?

    rate in Greece which is a developed country and has just 0.0106862 per 1,000 people being raped. 33 Who should have the vaccine? 14 The picture above shows Lauri Rupracht, a registered nurse giving an 11yearold girl one of the three shots that will immunize her against HPV.14 It is

  2. The Effect of Substrate on

    Yeast: It is very important to use the same batch of yeast so that its concentration is the same and it is all of the same quality otherwise there may be many factors of the makeup of the yeast, genetic or physical properties, which will affect the respiration rates.

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