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

Investigate how temperature affects the rate of anaerobic respiration in a sucrose & yeast solution.

Extracts from this document...

Introduction

Investigating the Fermentation of Yeast Aim: To investigate how temperature affects the rate of anaerobic respiration in a sucrose & yeast solution. Hypothesis: Temperature will affect the action of yeast. The rate of respiration will increase with temperature until the heat becomes too much & the enzymes in the yeast are denatured. Very low temperature will slow the rate of respiration & make the enzymes dormant/inactive. Theory: Yeast lives as single cells, its name 'saccharomyces' means sugar fungi. It is a fungus which acts as a biological catalyst. It has been used for many years in the process of fermentation. It is added to rice & barley to produce beer by anaerobic respiration. It is also used in dough, where it ferments in heat with the sugar forming carbon dioxide gas, which therefore causes the dough to rise. When added to a monosaccharide sugar (e.g.-Sucrose, Maltose, fructose, glucose etc.) it acts as a catalyst speeding up the reaction of anaerobic respiration (fermentation). The equation for anaerobic respiration is: Glucose (C6H12O6) --> Energy (ATP) + carbon dioxide (6CO2) + alcohol (2C2H5OH) It acts as a catalyst due to the enzymes it contains. Enzymes are substances made of amino acids that join with specific substrates to break them down. They have weak bonds joining them which can be easily broken. High temperature for instance will deform the active site & denature the enzyme. ...read more.

Middle

Control: * Only have one variable - temperature. * Control all other factors - pH of solution, concentration of solution, amount of air and solution in syringe. * Repeat each experiment twice for accuracy. * Use largest ice cream container possible to minimise lose of heat. (closest possible surface area:volume ratio to minimise lose of heat via diffusion) Uncontrollable Factors: * Slight lose of heat over the one timed minute- minimised by the use of a large container & the test only being timed for a short period. * Solubility of CO2 - carbon dioxide is very slightly soluble, 0.1688g per 100g of water (at room pressure & temperature) Results of the experiment: Temperature of water in container (�C) Number of bubbles CO2 produced, test one Number of bubbles CO2 produced , test two Average number of bubbles CO2 produced 8 0 3 1.5 22 9 8 8.5 32 12 13 12.5 45 42 42 42 58 64 72 68 85 11 10 10.5 (See Next sheet for line graph of results) Analysis: The results that were collected, shown on the graph on the following page, illustrate that my hypothesis was partly correct. The graph shows how the rate of respiration increased with temperature until, by 85�C, it had slowed dramatically. This proves my theory, that the enzymes in yeast, like those in our bodies, e.g. amylase, are more active with higher temperatures, however are denatured if the temperature becomes too high. ...read more.

Conclusion

However, this method can only help the situation and not solve it. On the first test that we did, we took the temperature at the end of the minute to test for accuracy in variation of temperature, only to discover that the temperature still changed by approximately 2�C. The only way to really solve this would be to use an electrically operated, thermostatically controlled water bath. However, this would make controlling the rest of the experiment much more difficult as it is a large, cumbersome device and it would be difficult to set up the equipment effectively. A final factor that I would change is a piece of equipment that we used- the syringe. Using tongs to hold the syringe in place under the water was necessary To prevent scalding however it made controlling the angle the syringe was held at difficult. The design of the syringe meant that any slight tilt off of horizontal caused solution to spill out into the container. One way to correct this would be to use less solution in each syringe so that the level of solution was further from the opening in the end. e.g.- Conclusion: Considering the means we had to carry out this experiment. ( i.e.- the equipment etc. ) The experiment went very well , however there are many areas of the method that could be improved upon to consequently get much more accurate results to not only be able to prove the hypothesis but also to be able to conclude on exact temperatures at which the enzymes become dormant, most active & finally denature. By Louise Martin 10ME ...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. Marked by a teacher

    Investigating respiration of maggots

    5 star(s)

    I must therefore bear this in mind when carrying out my investigation. - Life Cycle- Just like any other living organism the maggots are part of a life cycle. This cycle is shown below. Egg Adult winged Fly Larva (maggot)

  2. Marked by a teacher

    The Effect Of Temperature on the Respiration Of Yeast.

    5 star(s)

    This is what I predict them to look like. Rate of Reaction (1/Time) against Temperature: - I predict that this graph will show that as I increase the temperature the rate of reaction increases to a point where the enzymes denature so the reaction slows and eventually drops.

  1. Affect of sucrose concentration on the rate of respiration.

    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. Multiplication of yeast cells in aerobic and anaerobic conditions

    The larger flasks contained a larger percent increase due to there being more oxygen in the larger ones. More oxygen means aerobic respiration is much more rapid and therefore a more rapid cell division. The results prove that more energy is produced from aerobic respiration than anaerobic respiration: the smaller flasks contained less oxygen and therefore aerobic respiration was lower.

  1. The rate of respiration in yeast and how it is affected by temperature.

    I shall take readings from 25�C to 60�C at 10�C intervals. I will start from 20�C as I found out from my initial investigation that there was no respiration activity below this temperature. I shall proceed in this sequence as it is the easiest way of collecting results and will help to find out other flaws at a lower temp.

  2. Investigation into the Effect of Temperature on the Rate of Fermentation by Yeast.

    Group Temperature / oC 0 15 30 45 60 A 0 0 0.07 0.160 0 B 0 0 0.06 0.110 0 C 0 0 0.05 0.120 0 D 0 0 0.06 0.150 0 E 0 0 0.06 0.140 0 Average 0 0 0.06 0.136 0 Table 7.

  1. The aim of this investigation is to find out how concentration of glucose affects ...

    This time will be 30 minutes. In order to gain some information about using ranges and amounts of substances I should use, I performed some preliminary experiments. I started by using 10ml of 1 moldm-3 Glucose solution and then diluting that down to 80%, 60%, 40% and 20% of this original concentration.

  2. 'Investigating how temperature affects the rate action of the amylase enzyme on starch.'

    The colour will be brown when no starch is present (the colour of the iodine is blue/black) * I will finally note down the time it takes. This is will be the time taken for the reaction to be completed.

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