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

AS Biology Coursework:Investigating the effect of temperature on the rate of reaction of the essence rennet

Extracts from this document...


AS Biology Coursework 2002: Investigating the effect of temperature on the rate of reaction of the essence rennet Plan Rennet contains enzymes called chymosin, which have the property of clotting, or curding milk. Chymosins' coagulate the protein casein found in milk, forming solid curds. 0They firstly break down specific bonds in a glycopeptides found on the surface of soluble calcium caseinate that contain casein, leaving relatively insoluble calcium paracaseinate (unstable, denuded casein particles). These particles in the presence of calcium (2-) ions coagulate to form a continuous curd. This property of coagulating milk makes rennet a biological enzyme that is used industrially in the production of cheese, yogurt, and other diary products. There are many forms of rennet, derived from different sources using different methods. In this investigation I will be using calf rennet, this has been derived from the inner lining of the fourth stomach of a calf. Other forms include, Maxiren (100% pure chymosine, made using rDNA technology) and rennilase (a fungal protease). Chymosin, known also as rennin, is a proteolytic enzyme (made up of protein), which is most stable between pH 5.5 and 6.0 hence it is ...read more.


increase in temperature the substrate can not bind with the enzyme slowly decreasing the rate at which the enzyme catalyses the reaction (rate at which the milk is coagulated). Once the higher temperatures are used this causes denaturation which is irreversible as it is the destruction of the tertiary structure of the enzyme. The destruction of the tertiary structure leads to the change of shape of the enzyme, resulting in the inactivity of the active sites. I hypothesis the optimum temperature will be between 39C and 41C which I have estimated researching though average enzyme optimum efficiency. Method Key Variables: * For all individual experiments, the temperature will be kept constant at the temperature been tested Controlled Variables: * Calf rennet concentration will be the same for all experiments * Milk type (whole milk, semi-skimmed) will be kept the same for all experiments * PH of milk will be same for all experiments (buffer solution will be used if pH is compromised) * Repeat each experiment at least three times Equipment: Water bath Ice 2 Pipette Test tube rack Calf rennet Whole milk 2 Thermometer Scale (electronic) ...read more.


After 4 minutes I will stop the stop watch and remove the milk (liquid-solid) and place on a muslin cloth, where I will drain away requiring liquid in the substance. Once there is only clotted milk left I will weigh the remains and record it. I will attempt the experiments at least three times to achieve a fair set of results within the time given. Equipment layout: Risk Assessment: * Calf rennet (chymosin enzymes) Are in standardized solution form. Enzymes are biologically active proteins so should be handled with care. May also irate the skin, eyes or mucous membrane - Avoid direct contact - Avoid inhalation - Clean up spillages immediately - DO NOT ALLOW TO DRY AND GENERATE DUST- after spillage Pilot test: In order to determine a suitable range of temperatures I could use I carried out a pilot test of the experiment. Results of pilot tests: Using 1cm Mass of maslin cloth BEFORE Temperature Mass of maslin cloth AFTER Mass of remains 0.98g 21C 1.56g 0.58g 0.99g 30C 2.83g 1.84g 1.01g 36C 5.37g 4.36g 0.92g 40C 4.21g 3.29g 1.02g 65C 1.38g 0.36g The two rows highlighted in red is the range that holds the enzymes optimum temperature. ...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. A Level Biology revision notes

    � ES � P + E * Enzyme is not used up in the reaction (unlike substrates) Enzyme Activity * Changes in pH o Affect attraction between substrate and enzyme o Ionic bonds can break and change shape � enzyme is denatured o Charges on amino acids can change � ES complex cannot form o Optimum pH (enzymes work best)

  2. Trypsin. Hypothesis: - I hypothesize that as the temperature increases the rate of enzyme ...

    The two molecules form a temporary structure called the enzyme-substrate complex. The products have a different shape from the substrate and so, once formed, they escape from the active site leaving it free to become attached to another substrate molecules.

  1. Find out what effect different temperatures have on the enzyme, rennin, in milk.

    As the temperature ascends to beyond the optimum temperature required, there are an increased amount of permanent bonds made. Nonetheless, as these bonds are made the secondary structure of rennin has an effect on how the enzyme retains its shape.


    The enzyme is antibacterial because it degrades the polysaccharide that is found in the cell walls of many bacteria. It does this by catalyzing the insertion of a water molecule at the position indicated by the red arrow. This hydrolysis breaks the chain at that point.

  1. The effect of concentration of vegeren on clotting times with three different milks, whole ...

    These enzymes are most active in acidic environments i.e the stomach. Caseinogen is the main protein in milk. Caseinogen is milk caseins combined with calcium. It exists as a suspension in milk. There are four major types of casein molecules.

  2. Osmosis Coursework

    If the same cell is put in a solution of lower water potential, water will leave the cell and the vacuole. So, the protoplast will pull away from the cell wall. At this point, the pressure potential is zero and the water potential will reduce.

  1. mitosis coursework

    safety goggles Wear rubber gloves Do not touch eyes or mouth Keep away from any sores/ cuts My Results Prophase Metaphase Anaphase Telophase 17 7 8 18 Class results Name Prophase Metaphase Anaphase Telephase My results 17 7 8 18 Jenny 22 7 4 7 Julia 14 20 8 8

  2. Biology coursework

    I started by using a graduated pipette to measure out 2cm? of invertase solution. I put this into a small 50cm? beaker. I then used a different pipette to measure out 8cm? of Sodium alginate. I added this to the invertase.

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