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

Yeast fermentation

Extracts from this document...

Introduction

What effect does sugar have on yeast reproduction? IB Biology Veronika Brantov� May 2008 Defining problem and selection variables Purpose The purpose of this lab is to find out what effect has sugar on yeast in different concentrations of sugar. Background information Yeast is a fungus and needs a supply of energy for its living and growth. Sugar supplies this energy. Yeast can use oxygen to release the energy from sugar in the process called "respiration". So, the more sugar there is, the more active the yeast will be and the faster its growth (up to a certain point - even yeast cannot grow in very strong sugar - such as honey). However, if oxygen is short or not present, then yeast can still release energy from sugar, but in these conditions, its byproducts are alcohol and carbon dioxide. This process is called fermentation. To introduce this laboratory, a number of foods are produced by fermentation such as yogurt, buttermilk, yeast breads, sour cream, etc. Sugars are the common substrate of fermentation. The alcohol and the carbon dioxide are waste products produced by the yeast, which we can see on the equation below. C6H12O6 2CH3CH2OH + 2CO2 + Energy Simple Sugar Etanol Carbon Dioxide Table 1. Comparison of respiration and fermentation of sugar in yeast. Process Conditions Products from sugar Amount of ATP Respiration Aerobic 6 CO2 + 6 38 Fermentation Anaerobic CO2 + 2 C2H6O 2 Hypothesis If we limit the oxygen that ...read more.

Middle

Error reduction I made sure that the amount of yeast used in each fermentation flask was the same (because I used a scale). I tried to reduce air us much as possible by rubber stopper. Method of Collection Procedure is proper and goes in order I stated above. Data Flask A - Day 1 Time has passed CO2 produced Total 9:45 0.25hour 0ml - 12:00 2.5hour 1ml - 15:00 5.5hours 1ml - 2ml CO2 Flask A - Day 2 Time has passed CO2 produced Total 8:00 23.5hours 5ml - 12:00 26.5hours 2ml - 15:00 29.5hours 2ml - 9ml CO2 Flask A - Day 3 Time has passed CO2 produced Total amount 8:00 47.5hours 9ml - 9ml CO2 Flask A Total amount CO2 produced that day Day 1 2ml Day 2 9ml Day 4 9ml Together 20ml The amount of carbon dioxide produced in flask A, with one gram of sugar is watched and written down in the charts above the final amount after 47.5 hours is 20ml of CO2. Flask B - Day 1 Time has passed CO2 produced Total 9:45 0.25hour 1ml - 12:00 2.5hour 3ml - 15:00 5.5hours 6ml - 10ml Flask B - Day 2 Time has passed CO2 produced Total 8:00 22.5hour 26ml - 12:00 26.5hour 9ml - 15:00 29.5hours 9ml - 44ml Flask B - Day 3 Time has passed CO2 produced Total 9:45 47.5hour 25ml - 25ml Flask B Total amount CO2 produced that day Day 1 10ml Day ...read more.

Conclusion

Besides that there was the chance that sugar was not dissolved completely Limitations The worst limitation was the problem of lack of time therefore I could not repeat the laboratory process. Besides that supplies were limited therefore I could not use more flasks and beakers to expand my experiment. Improving Ways of improvement The procedure of this experiment could be improved, although the results do give adequate results. Improvements would simply remove certain errors, and improve the accuracy of results: A better overall result would be obtained by repeating the experiment more times. But because the purpose was to show the effect, which I successfully managed to achieve - the result was according to my background information I believe that repetition of the experiment would show slightly different values but the overall result which in this case is the most important would be the same. I should ask another person for help during the preparation time so all testing tubes are set at the same time and not one after another. In order to show better results I could have done one experiment of aerobic respiration and compare the difference. Another idea that may be worth investigating would be the effect of water temperature. So perhaps by increasing the temperature of the solution that the yeast is in, we would see less oxygen in the water at the end of the experiment because more sugar would be in solution and therefore more accessible to the yeast for use. Related to weakness/limitations Using more different concentrations of sugar would have produced a better looking data. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Biology 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 International Baccalaureate Biology essays

  1. The effect of the tempereature on yeast metabolism.

    When heat is applied to the enzyme, energy is given off. The active enzyme cell deforms and the hydrogen bonds break, denaturing the yeast enzyme. It would not be able to function as usual, and this process is irreversible. c.

  2. Bio lab - Oxygen Consumption in germinating and non-germinating seeds

    The differences are calculated by subtracting final value from the initial value. The actual differences are calculated by subtracting the differences in control from the differences in germinating/non-germinating seeds. Temperature (�C�1�C) Time (min) Differences in Control (Beads) ml�0.01ml Differences in Germinating Seeds ml�0.01ml Actual differences in Germinating Seeds ml�0.01ml Differences

  1. The effect of toliet cleaning products on E-coli ...

    In contrast a substance that simply inhibits reproduction can be designed to be specific to e-coli's reproduction enzyme/s rather than the entire cell, hence increasing the safety of the product. Outside of the biological field implications may exist. In particular would be the commercial implication.

  2. Reaction Time

    are constantly carried out. Looking at these brief introductions to the different sports we can try to group them into different categories. The most relevant grouping seems to be: Sports Including Reaction Time Drills (SIRTD), Sports Not Including Reaction Time Drills (SNIRTD)

  1. How does changing the percentage of sucrose added to yeast affect the rate of ...

    This error bar also overlaps the three other data points (10%, 15% and 20%) this indicates that there may be no clear trend in our results due to this overlap. The error bar for 20% is also large, that there were considerable differences in the data points, indicating that our results for 20% may not have all been very valid.

  2. Comparing the Sexy Sons Hypothesis and the Pathogen Avoidance Models Effects on Sexual Selection

    They then mated one moth with a single male three times and the other once with three different males. What they found was that sons produced from the polyandrous relationship had increased reproductive success. They produced around 81% of the total number of offspring including the monandrous line males.

  1. Investigation Of Factors That Affect Carbon Dioxide Production In Yeast

    Similarly, starch, as a polysaccharides, is also harder to be metabolized than Fructose. In addition, strach is degraded by the enzyme amylase, which is found with very limited quantity in yeast. Lactose needs to be broken down by the enzyme lactase only, which is scarcely found in many types of yeast.

  2. What is the effect of pH levels on the net production, given by the ...

    Control Group: Chlorella pyrenoidosa in pH 8 buffer solution. Experimental Groups: Chlorella pyrenoidosa in pH 6,7,9,and 10 buffer solutions. Materials: 25 BOD, large bottles (closed using black cap) capable of holding up to 150 mL of liquid Graduated cylinder for measuring pH buffer solution quantities and Chlorella pyrenoidosa sample quantities (uncertainty +/- 1mL)

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