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

Investigation of the effect of different carbohydrate substrates on yeast growth

Extracts from this document...


"Investigation of the effect of different carbohydrate substrates on yeast growth" Yeasts are eukaryotic microorganisms classified in the kingdom Fungi. The cell walls made of Chitin and they can be found virtually everywhere; "on the skin, on some fruits, in the soil and some are airborne" Saccharomyces cerevisiae are the species of yeast to be used in this experiment. They are used in industry due to the secretion of enzymes that they produce which breaks down sugars by two means aerobically or anaerobic. Aerobically (sugar + Oxygen --> Carbon dioxide + Water + 38 ATP energy) and anaerobically (sugar --> Ethanol + Carbon dioxide + 2 ATP) as this experimental investigation is about the growth of yeast, the main equation is the aerobic one due to it provides 38 ATP energy for cell division either by means of mitotic growth (asexual/ budding) which is the more common type of growth or by means of meiosis (sexual reproduction). The energy is necessary for the oxidising the sugar (C6H12O6/ glucose) into pyruvate, glycolysis happens in the cytoplasm. I will experiment three different sugars; glucose a monosaccharide; maltose a disaccharide and sucrose Alternative hypothesis Glucose will have the largest effect on yeast growth. ...read more.


3. washing hand after experiment will be advised. Procedure 1. I will collect all the apparatus. 2. I will label the test tube 1,2,3 and c; 1 will be the glucose solution affecting the yeasts growth;2 will be the maltose solution affecting the growth of the yeast;3 will be the sucrose solution affecting the yeast growth; c being the control group with no carbohydrate just distilled water 3. I will measure 10 gram of the carbohydrates on the balance pre setting the balance to zero with filter paper on it ass I will only be using the carbohydrates. This 10 grams of the named carbohydrates will be added to 90 cm3 of water to make a 10 % solution of carbohydrate. I will stir the solution for 15 seconds. 4. due to high percentage of yeast I will perform serial dilution making the yeast percentage lower and easier to count underneath the light microscope ast next; 1ml % of yeast into 9ml of solution making it 0.1% yeast then I will pipette 1ml of the 0.1% yeast into 9 ml of solution making the yeast 0.01% and dilte enough to use for counting. ...read more.


0 1 2 3 4 5 6 24 25 26 * * * * * The data and graph Lag time where the yeast cells are not dividing; there is only an increase in cell mass, but not in cell number due to adapting to their environment. Log; time where there's an exponential growth, the population can increase exponentially due to no limiting factors. Stationary time where number of new cells formed is equal to the number of cells dying. Limiting factors, such as nutrient supply, have started to influence further increase in population size. Death; time for autolysis. they have run out of supply and digest themselfs. The statistical test This test will be done to either accept or reject the null hypothesis. The equation below is the one that will be used to work out the value of chi squared. O= the observed result E=the expected result Degree of freedom is the number of environments and subtract one of it. In this experiment 3 -1 = 2 df, 0.05 probability, if the value is less than 5.991 than one can accept with 95% confidence the null hypothesis. ?? ?? ?? ?? Ali Reza Nazokkar A2 Biology coursework planning 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 Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

**** A good A-level biology experiment plan, which attempts to present experimental steps and justifications clearly. The rationale lacks A-level biological detail and does not set the investigation in context. To improve:
1)Set the investigation in context, including A-level biology
2)Explain why all control variables should be controlled in term of their potential impact on the growth of yeast, including relevant background biology
3)Ensure that it is clear that each experimental condition (i.e. carbohydrate type in this case) will be repeated the number of times required for the statistical test
4)Justify the statistical test in terms of the effect under investigation and the range or repeats collected
5)Describe how the raw data will be processed, for example yeast cell number should be converted into growth rates to reveal key differences. Cell number is not a measure of growth

Marked by teacher Kerry jackson 29/03/2012

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 Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Sand Dune Succession Coursework

    5 star(s)

    other plant species can take hold of the stabilised surface such as red fescue and mosses. Grey dunes are much more stable and mosses and lichens fill the few remaining spaces so that vegetation over may reach 100%. Marram grass becomes less common and plants such as red fescue and sea spurge begin to dominate.

  2. Marked by a teacher

    Mr Chips: Investigation to find an isotonic solution for potatoes

    4 star(s)

    % change in mass Concentration NaCl solution % Mean Percentage Change in Mass % 0.0 4.8 0.5 -1.0 1.0 -4.8 1.5 -16.5 2.0 -21.0 3.0 -26.3 A graph has been created to visualise the trends in these results. Discussion On analysis of the results and the line graph a similar trend to that of the preliminary results can be seen.

  1. Marked by a teacher

    An investigation on the effect of temperature on beetroot membrane structure.

    4 star(s)

    (Ref 6) Safety issues: Care must be taken when using the cork borer as it may hurt you while trying to get it in to the beetroot. In addition, lab coats must be worn as you are always using beetroot and they are around you, so you must be careful

  2. Marked by a teacher

    Describe the molecular structure of starch (amylase), glycogen and cellulose, and relate these structures ...

    4 star(s)

    It is made by animals as their storage polysaccharide, and is found mainly in muscle and liver. Because it is so highly branched, it can be mobilized (broken down to glucose for energy) very quickly. Glycogen molecules clump together to form granules, which are visible in liver and muscle cells where they form an energy reserve.

  1. Peer reviewed

    The Importance and Biological Functions of Carbohydrates.

    4 star(s)

    The highly branched structure means that it is readily mobilised for an animal's energy demand. Cellulose is a very strong, structural polysaccharide. It forms a very important component of plant cell walls. It is formed form ? glucose. The molecules are linked by condensation and so in order to get

  2. Investigate the effect different concentrations of glucose in a yeast & Glucose solution has ...

    You must then mix the yeast and glucose in a conical flask and place the bung in the top as soon as possible, and start the stopwatch. After 3 minutes take a recording of how much water is in the burette take the first reading of water from the burette

  1. Compare and contrast the digestion and absorption of carbohydrates and lipids.

    Besides having important roles in membranes, lipids are stored, mainly in adipose cells, and used in cells as an energy source, for when food supply is low. Lipids link covalently with carbohydrates to form glycolipids and with proteins to form lipoproteins.

  2. Fermentation of different sugars by yeast.

    measured by looking at how the level of the dough rises at frequent intervals. By looking at this we can see the rate of fermentation, by exploiting this manifestation of anaerobic respiration. Then by changing the substrates or the temperature we can see the effect of them on respiration.

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