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

To find the effect of different concentration of calcium ions on the rate of coagulation of milk.

Extracts from this document...


Aim: To find the effect of different concentration of calcium ions on the rate of coagulation of milk. Background Research: protein molecules can take different types of structures. It's made up of several hundreds of amino acids joined together by peptide bonds. There are four different structures of protein molecules: 1. Primary structures: this is where a chain of amino acids are bonded by peptide bonds to form a polypeptide chain. 2. Secondary structures: there are two of these kind; * Alpha helix - the amino acids are bonded with other amino acids in the same polypeptide chains via hydrogen bonds between the -CO and -NH groups. A coiled structure of amino acids form. * Beta pleated - this is where the arrangement is much straighter than the previous type, although hydrogen bonds exist between the amino acid. 3. Tertiary structures: here, the secondary structure of a protein is further bonded into a more complex structure. This is due to several types of bonds that occur between the polypeptide chains. ...read more.


Risk Assessment: Sodium citrate is irritant when exposed to the skin. CaCl2 is also irritant to skin and eyes. However lower concentration will not pose any real threat although precautionary measures must be taken. Therefore, goggles and lab coats must be worn. Apparatus: Rennin solution 1ml syringe Milk 5ml syringe Sodium citrate 10ml syringe Testubes 50cm� beakers 1.0 mol dm of calcium chloride 50cm� measuring cylinder Distilled water Microscope Microscope slides Plastic Pipette Stop clock Method of Dilution: As only 1.0 mole dm-3 of CaCl2 is provided, I need to dilute it down to several concentrations. However, from preliminary testing, I found that 1.0 mol dm-3 is far too strong for the reaction as it forms flecks of curd instantly. Therefore I have decided to have my highest concentration as 0.5 moles dm-3. In order to dilute, I will have a total of 20cm� solutions of calcium chloride and water. To get different concentrations, I will change the ratio of CaCl2 to water. ...read more.


This varies from batch to batch. Therefore, I will have to assume that all calcium ions are removed. Then, 3. Using a 1ml syringe, add 1cm� of Rennin into each beakers containing milk. 4. For each of the beaker, add different concentrations of CaCl2 respectively using a 50cm� measuring cylinder and start recording the time. 5. As soon as the different concentrations of CaCl2 is added, dip a microscope slide in to the solution, remove it and observe it under a microscope to look for the appearance of flecks of curd. I will record the time it takes for flecks of curd to appear. Diagram: I will repeat the above experiment at least three times in order to get reliable information. Results Table: Beaker Vol. of Milk (cm�) Vol. of diluted CaCl2 (cm�) Conc. of CaCl2 (mol dm-3) Coagulation time(s) 1 10 20 0.50 2 10 20 0.25 3 10 20 0.125 4 10 20 0.10 5 10 20 0.0625 6 10 20 0. ...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

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

    Biology coursework planning - the effect of lead chloride on the growth of cress ...

    5 star(s)

    It can be seen that lead has many adverse effects on the growth of plants. This investigation will observe exactly how varying concentrations of lead chloride affect the growth of cress seedlings. Prediction: Based on my findings on the effects of lead chloride on plant growth, I predict that as

  2. Marked by a teacher

    What is Type 1 diabetes

    3 star(s)

    in the blood. How is diabetes treated? Diabetes is treated in two ways: a combination of proper diet and exercise medication with tablets or insulin. For Type 1 diabetic patients, and some Type 2 diabetics, insulin injections will increase the insulin level in the blood and bring down the blood sugar level.

  1. Peer reviewed

    The comparison of antibacterial properties of herbal products and standard antibiotics

    5 star(s)

    As already stated the results do not prove the hypothesis to be correct but nor incorrect so they therefore weren't what expected and followed a different trend, in which supported the null hypothesis, where no significant statistical difference occurred. Some problems were encountered with trying to sterilise the bacteria bottle tops and keep the lids tightly held.

  2. Peer reviewed

    Effect of Caffeine on the Heart Rate of Daphnia

    3 star(s)

    is actually proportional to the heart rate of Daphnia. Observing the Daphnia under the light microscope, the heart rate of Daphnia is recorded by counting the beatings of the legs of Daphnia in 15 seconds. 3. Constant variable: Temperature of the environment of Daphnia (water flea), time of recording heart beat, type of Daphnia (water flea)

  1. Effect of Caffeine on the Heart Rate of Daphnia

    Due to fairly slow human reactions, it is only possible to measure the time of the reaction to the nearest 0.1 second even though the stopwatch shows measurements to the nearest 0.01 second. 5. Miscalculations may occur during the calculation of the heart beat.

  2. Investigation into the effects of different

    Fixed variables 1. temperature; it would be fixed at 25�C , which is the optimum temperature for yeast growth, as yeast have an optimum temperature range from 20�C -30�C .This will be controlled by fixing the temperature of the water bath at 25�C.If the temperature was way below the chosen e.g.

  1. Plan an investigation to find out what effect changing the concentration of calcium ions ...

    * pH - pH is a measure of hydrogen ions, which can interact with the r group of enzymes and so affect there structure, most enzymes work best around a neutral pH. Milk proteins are made up of 80% [1] molecules called casein which can be split into 4 groups, Alpha-s1, Alpha-s2, Beta and Kappa.

  2. This experiment aims to investigate the effects of 4 different types of fish food ...

    Mosquito Larvae provide the bulk of the diet of Guppy fry in the wild, and the experiment had to be carried out when they are in season. It has been suggested that natural foods contain the highest vitamin and mineral content; however, they also contains a high percentage of water and indigestible fibre, which offers no nutritiona l value.

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