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

Investigation to see what effect the changing the concentration of calcium ions has on the rate of coagulation of milk by Rennin.

Extracts from this document...


Aim : Investigation to see what effect the changing the concentration of calcium ions has on the rate of coagulation of milk by Rennin. Theory Most milk proteins are caesins, which have four major forms: alpha-s1, alpha-s2, beta and kappa caesins. Alpha and beta caesins, when left on their own would precipitate in the presence of calcium. However, when associated with unperceivable kappa caesins, also present in milk, they form micelles which remain dissolved. (ref1) Rennin digests kappa casein, preventing it from aggregating the alpha and beta caesins into soluble micelles, effectively causing them to precipitate out naturally.(causing coagulation) And this precipitation requires calcium ions. Apparatus Rennin solution (50-100ml) Milk 2ml per 20cm� of milk. Sodium citrate solution, 2cm� (per test tube) 1.0 mol dcm� Calcium chloride solution Hot water bath set at 37�C 5 Test tubes 5 Pipettes 1 test tube rack Stop watch, to measure the time taken for the flecks or curd to appear. Safety goggles, to protect eyes from harmful chemicals. Syringes Slides, to dip into beaker/test tube. Introduction The problem that I am faced with is to get a sample of milk and try changing the concentrations of the calcium ions that are present in it. ...read more.


PH level; Enzymes are specific in their optimal pH. Calcium chloride is likely to be a weak acid because of the chlorine molecule, in which case it can have an affect on the enzyme. Rennin is accustomed to working in extremely acidic conditions and to tamper with that may damage the enzymes active site temporarily or permanently resulting in it not working, so I shall have to maintain pH, as close to being acidic as possible. During the conduction of this experiment I shall have to try and keep these factors the same. Prediction I predict that the higher the concentration of the calcium ions is the quicker the rate of coagulation of milk. This will happen because the more calcium ions there are, the higher the production of casein protein precipitation taking place at a time. Method The first step in this experiment is to add around 20cm� milk to the test tubes using a syringe to each of the five test tubes. I shall also have 5 different concentrations of sodium citrate solution to remove either all or some of the calcium ions that are present in the milk. ...read more.


I shall work out the rate of coagulation by doing. 1 / Time taken. Calcium Chloride Concentration(cm�) Time taken (s) 0.1 0.05 0.025 0.0125 0.0625 30 60 90 120 This I what my table of results will look like, with time taken for coagulation on the side and the concentrations of calcium chloride on the side. Precision and Reliability In order to get the most accurate of results I shall have to perform the experiment with the highest precision and reliability. For precision my measured values of calcium chloride and rennin solutions should be as close as possible to their actual values. The equipment that I will use for maximum precision are measuring cylinders, pipettes and rulers that measure to the nearest millimeter. For reliability I shall repeat the experiment that I have conducted at least 6 times and use the average of the results. Safety As I will constantly be in contact with irritant chemicals, I shall have to handle them with the utmost caution and also remember to wash my hands thoroughly after direct contact. I shall also be wearing safety goggles as rennin is a protein digesting enzyme, any contact with the eye can be extremely dangerous. Sources http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Laboratory/Enzymes/Enzymes.htm. (ref1) http://en.wikipedia.org/wiki/Rennet (ref2) ?? ?? ?? ?? Asad Shahid. 4195 51529 ...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. Affect of concentration of calcium ions on the coagulation of milk

    Another possible hazard is broken glass. Be careful with glassware, if any glass is broken don't attempt to tidy it up yourself, ask a lab technician or teacher to do it for you. Tie up long hair and clean up any spillages immediately.

  2. An Investigation On The Effects Of Calcium Ions On The Coagulation Of Milk

    and to reduce results being called into question by the effect of changing external factors. These are the precautions which I took to ensure the above criteria are met: * All experimental work will be performed in the same area on the same day.

  1. Calcium ions effect on the rate of coagulation of milk

    Method: IV: Concentration of calcium ions DV: Rate of Coagulation of the milk Constants: Temperature, PH, Sodium concentration, Concentrations of the substrate After the successful conclusion of the Preliminary Tests, I would use from 0.0 mol to 1.00 mol calcium chloride.

  2. An experiment to investigate the effect of enzyme concentration on the rate of milk ...

    * Using the table below as a guide I will produce the different concentrations of lipase enzyme, each in there own marked beaker. Desired Enzyme Concentration (%) Amount of Enzyme (cm�) Amount of Distilled Water (cm�) 1 2 8 2 4 6 3 6 4 4 8 2 5 10

  1. Investigation to find out what effect changing the concentration of calcium ions has on ...

    coagulation, I will observe how long it takes for flecks of curd to first appear on a microscope slide dipped into a sample of milk. Safety Problem Hazard Caused Solution Calcium Chloride (and Sodium Citrate) Irritant to eyes, skin and if inhaled or ingested Eyes and skin should be washed out with plenty of water.

  2. Amylase Investigation

    * 10 ml Syringe * Stop clock This apparatus was used in order to accurately measure substances and time to gain a reliable set of results. For example, the syringe will allow me to measure exactly how much starch and amylase to use and the thermometer will allow me to measure the exact temperature of the water bath.

  1. Catalyse Investigation

    Then the sheet on which I put the information to be transferred to graphs. Then come the graphs in a numbered order. They need no explanation as they have complete headings. The computer plotted the lines of best fit and some are more roughly sketched than others are.

  2. Investigating the effect of varying the concentration of calcium chloride on the coagulation of ...

    Now coagulants used contain no pepsin and are much less dependent on calcium for good coagulation. However, the addition of calcium chloride can help to reduce the amount of coagulant needed to achieve a proper set. While the addition of CaCl2 is legally allowed up to 6 oz per 1000 lb of milk, its overuse can result in short-bodied cheese.

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