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

An Investigation to Show the Effects of changing temperature in Yeast Respiration.

Extracts from this document...

Introduction

Science Coursework - An Investigation to Show the Effects of changing temperature in Yeast Respiration. Brief Investigate one of the variables that effect respiration in yeast. Background Knowledge Yeast is one of the various single celled fungi that form masses of miniature circular or oval cells by budding. When placed in sugar solution the cells multiply and convert the sugar solution into alcohol and carbon dioxide. Yeasts are used as fermenting agents in baking, brewing and the making of wine and spirits. Brewers yeast is a rich source of vitamin B. Respiration in yeast is the production of the energy in the mitochondria of the cells. There are 2 types of respiration, Anaerobic and aerobic. At first aerobic respiration will be present but only until the oxygen that is already dissolved in the water. When the oxygen is used up anaerobic respiration will be present which produces the alcohol. The word equation for anaerobic respiration in yeast is: Glucose Alcohol + Carbon Dioxide + Energy Anaerobic respiration is different in humans than it is in yeast because we break down glucose into lactic acid whereas yeast breaks it down into alcohol. ...read more.

Middle

water the same throughout the investigation * Let the solution stand for the same amount of time each time, five minutes * Add the yeast only when the sugar solution is at the correct temperature Safety This investigation isn't very dangerous; I will only have to be careful when handling the hot water. Analysis From my results you can see that the yeast reacts better between 35-50 C. This is because at 20 C the water was too cold to give the enzyme any energy. At 65 C there was not much reaction, I recorded an average of 2.5 bubbles of carbon dioxide. This was because the water was too hot and when the water is too hot the enzyme deforms and changes shape as shown in my prediction diagram. It gave off a few carbon dioxide bubbles at the beginning before it changed shape so maybe at 50 - 60 C the yeast will react better as it didn't change shape straight away. At 80 C the water was far too hot, this would have changed the shape of the yeast straight away. ...read more.

Conclusion

I had to wait for it to start to respire, but this was the case in all the tests so in a way it was fair. Accuracy of Measurements All of my measurements were accurate. This was because I used an electronic set of scales to weigh the yeast and the sugar. Another reason why my test was accurate was that we used a thermometer to check the temperature that is an accurate means of measuring heat. It would have been even more accurate if we used an electronic thermometer. Improvements to Plan The only major improvement that I think would have been useful would be to increase the temperature by only 5 C each time instead of 15 C. This would help us to get a more accurate measurement of when the yeast respires best. If I had more time I would have done this and would have been able to find the optimum temperature for the yeast. Another improvement would have been to measure the amount of carbon dioxide given off instead of counting the bubbles. This would have been a good improvement as bubble sizes change, they are never the same size. ...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 Green Plants 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 Green Plants as Organisms essays

  1. Photosynthesis Investigation

    During the experiment we will need to wear gloves and lab coats. While turning the flame on for the Bunsen burner always try to keep hands as far as possible. Never touch beakers with naked hand when it has been heated.

  2. Experiment to investigate the effect of temperature on respiration in yeast.

    From what the graphs and tables told me, it has proven my prediction wrong. My result I think were good and told me what I think is the right answer, I think now I have done the experiment that I should have done more experiments and really proven my conclusion with more than a few graphs.

  1. The effect temperature has on the rate of anaerobic respiration in yeast.

    enzymes start to denature and they no longer have a use because the substrate doesn't fit in the enzyme. Evaluation: I ensures safety in the experiment by using goggles to protect my eyes and rubber gloves to protect my hands from the heat of the water when I held the syringe underneath the water.

  2. What is the effect on the rate of respiration of yeast cells with glucose ...

    250ml beakers To hold large volumes of water. It is large enough to allow hot water from the kettle to be poured into it. Conical flask To contain yeast and glucose solutions. It is the appropriate size for holding the volume of gas produced. Spatulas Measuring out the correct masses of yeast and glucose It is easy to handle as it is light in weight.

  1. Investigating The Fermentation of Yeast

    the amount of bubbles given off by both of the tubes slowed down. I think this may have been caused by the drop in the water's temperature as time went on as the heat was radiated away, or the yeast may have used up the glucose and slowed the fermenting right down.

  2. An Investigation into Species Diversity with distance along a Pingo.

    dominance which sees the strongest species survive as they are best-adapted and continue to develop, pushing other species out of the area. Succession can be seen across the pingo, where the vegetation changes from grasses and herbs to shrub and finally trees and woodland.

  1. The effects of organic effluent from the seweage on the biodiversty in a freshwater ...

    The density of these blooms increases to a point where light is unable to penetrate to any depth. The algae in the deeper regions of the lake are therefore unable to photosynthesis and die. Decomposition of these dead organisms by saprophytic bacteria creates considerable BOD resulting in deoxygenation of all but the upper layers of water.

  2. Yeast Investigation

    Also the yeast itself could have an affect on the time we leave it as well. This would because the cells that are in the yeast may have all respired after a certain time making our results suddenly drop because all of the respiring of the yeast we used would have been done.

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