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

Growing Micro-organisms

Extracts from this document...


Growing Microorganisms Introduction/ Aim: Yeast are a tiny form of fungi or plant-like microorganism (visible only under a microscope) that exist in or on all living matter i.e. water, soil, plants, air, etc. The yeast life cycle, like that of all higher organisms, includes a step known as meiosis, where pairs of chromosomes separate to give new combinations of genetic traits. People in today's society use yeast for controlled fermentation of food and drink; it is also used for baking. In this experiment I will be attempting to measure the growth of a yeast population and in doing this I will have to carry out certain methods to succeed. Below is a diagram on a yeast cells with arrows showing the parts of the yeast cell: Equipment/ Apparatus: * 250cm� Beaker * Measuring cylinder to measure 50cm� * A Cuvette * A Colorimeter * Sticky Labels * A Suspension of Yeast * Glucose Solution * Pipette Risk Assessment: This experiment is not that much dangerous so not much precaution is really needed, there are not dangerous chemicals, no hazardous gases etc. Below I have written the things you must look out for when carrying out this experiment. * You will be handling many glass equipment when doing this experiment such as beakers and measuring cylinders, you must be extremely careful ...read more.


In humans toxic waste is excreted by the kidneys (Urea) however waste products from microbes build up in the environment and can kill them e.g. more than 15% alcohol is capable of killing the yeast cells making the alcohol. Procedure/ Method: 1. To begin the experiment you must firstly collect a 250cm� beaker and place it down where you are going to do your experiment, you must then start off by using a measuring cylinder and measure out exactly 10cm� of yeast suspension, make sure you don't spill any yeast because yeast has a bad smell. 2. You must then pour the yeast from the measuring cylinder into the beaker and then rinse out the measuring cylinder and then measure out 200cm� of glucose solution and then pour it into a clean unused beaker; you must then stir very very gently. 3. Now you must rinse out the measuring cylinder and all the other equipment that have already been used and then place them onto the trolley. 4. At this point of the experiment the beaker must have a very small population of yeast cells which will grow within a few days times. You must now take a clean cuvette and fill it with a sample of your yeast population using a pipette, after that you must then collect your colorimeter and put it on, at this period of time it will begin to warm up. ...read more.


Another improvement we could have if we was to use additional equipments in our experiment such as a Ph sensor, temperature control, exit gas and exit liquid flow, antifoam and so on. The Ph sensor would be helpful because we will be able to identify the Ph level and we could be able to adjust it using certain methods, the temperature control could be helpful because we wouldn't want to kill the yeast population so therefore having control over the temperature would be helpful, the exit gas and exit liquid flow would be helpful in the experiment because we will then be able to remove the waste products. Final Conclusion: Overall, from doing this experiment I think that it was successful and I came out with the results that I was expecting at the beginning of the experiment, improvements can be made to the experiment such as changing the method of the experiment and this may result in having more accurate results. From doing the experiment and this coursework I managed to prove that as the yeast population increases it will become more difficult for the light rays to pass through the yeast population filled cuvette and this will decrease the transmission percentage. ...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. Cell death during embryogenesis

    When this is done, the cell density in the embryo is nearly doubled within 1 hour following the expression of CYCLIN E. Examination of cell death in these embryos shows that hyperplasia induced by CYLCIN E expression is largely

  2. Enzymes and Micro-organisms

    at * You can put it into a ph that only that micro-organism survives at * And a concentration that only it survives at To produce enzymes from a micro-organism the organisms need to be grown or cultured. The organisms are grown in growth or culture media.

  1. An investigation to find the lowest temperature that kills all the yeast cells in ...

    I intend to discover which temperature will denature all the yeasts enzymes and kill it; to do this I can use a solution called Methylene blue. In a living cell Methylene blue is oxidised from a blue to a colourless colour, this reaction can only take place in a living cell so cells that stay blue are dead.

  2. Fermentation of Yeast

    double the rate of reaction (enzymes). Prediction From looking at my background information I know that the optimum temperature of enzymes that are present in the yeast work at 40 .This means that when enzymes are above 40 they become 'de-natured' and therefore are unable to do their job!

  1. Anaerobic Fermentation By Yeast.

    To control this reaction the yeast has an enzyme; this enzyme is called Zymase. Zymase is an enzyme that acts on a certain carbohydrate to produce carbon dioxide and water, or alcohol and carbon dioxide . From http://www.webref.org/biology/z/zymase.htm Enzymes are used to control the speed and the rate of the

  2. The factors that affect the respiration of immobilised yeast

    For fermentation of occur, yeast requires a source of carbohydrates, anaerobic conditions and a suitable temperature. Fermentation stops when the yeast becomes poisoned by its own waste, the alcohol, which acts as a non competitive inhibitor to the enzymes involved in the process.

  1. Respiration in Yeast.

    This respiration process is called fermentation. The yeast breaks down the glucose using a series of enzymes. I deduce from this that the more glucose that is present in the yeast the more will be broken down and therefore more CO2 and ethanol will be produced as waste products at a faster rate.

  2. Observe how temperature affects the metabolism of microorganisms by visibly noting the volume changes ...

    Independent Variable Dependent Variable Control Constants Temperature * High temperatures (35 C) * Room temperature (24 C) * Low temperature The number of yeast reproduced * Constant class temperature * Constant fridge temperature * Constant Incubator temperature * # of yeast in each Petri dish * Volume of H2O *

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