Research Into Enzymes For Biology Rennin Rennet example essay topic

Research into Enzymes - For Biology Rennin Rennet, substance found in the gastric juices of young milk-drinking mammals. Rennet contains a milk-coagulating enzyme, called rennin or, the active principle of rennet preparations used in making cheese and junket. Rennet extracts are commercially prepared from the inner lining of the fourth stomach of calves. Enzymes Enzymes are large proteins that speed up chemical reactions.

In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. The enzyme itself is unaffected by the reaction. When the products have been released, the enzyme is ready to bind with a new substrate. Enzyme, any one of many specialized organic substances, composed of polymers of amino acids, that act as catalysts to regulate the speed of the many chemical reactions involved in the metabolism of living organisms.

The name enzyme was suggested in 1867 by the German physiologist Wilhelm K"uh ne (1837-1900); it is derived from the Greek phrase en, meaning 'in leaven. ' ; Those enzymes identified now number more than 700. Enzymes are classified into several broad categories, such as hydrolytic, oxidizing, and reducing, depending on the type of reaction they control. Hydrolytic enzymes accelerate reactions in which a substance is broken down into simpler compounds through reaction with water molecules. Oxidizing enzymes, known as oxidases, accelerate oxidation reactions; reducing enzymes speed up reduction reactions, in which oxygen is removed. Many other enzymes catalyze other types of reactions.

Individual enzymes are named by adding are to the name of the substrate with which they react. The enzyme that controls urea decomposition is called urease; those that control protein hydrolyses are known as proteinases. Some enzymes, such as the proteinases trypsin and pepsin, retain the names used before this nomenclature was adopted. PROPERTIES OF ENZYMES As the Swedish chemist J"ons Jakob Berzelius suggested in 1823, enzymes are typical catalysts: they are capable of increasing the rate of reaction without being consumed in the process. Some enzymes, such as pepsin and trypsin, which bring about the digestion of meat, control many different reactions, whereas others, such as urease, are extremely specific and may accelerate only one reaction. Still others release energy to make the heart beat and the lungs expand and contract.

Many facilitate the conversion of sugar and foods into the various substances the body requires for tissue-building, the replacement of blood cells, and the release of chemical energy to move muscles. Pepsin, trypsin, and some other enzymes possess, in addition, the peculiar property known as autocatalysis, which permits them to cause their own formation from an inert precursor called zymogen. As a consequence, these enzymes may be reproduced in a test tube. As a class, enzymes are extraordinarily efficient.

Minute quantities of an enzyme can accomplish at low temperatures what would require violent reagents and high temperatures by ordinary chemical means. About 30 g (about 1 oz) of pure crystalline pepsin, for example, would be capable of digesting nearly 2 metric tons of egg white in a few hours. The kinetics of enzyme reactions differ somewhat from those of simple inorganic reactions. Each enzyme is selectively specific for the substance in which it causes a reaction and is most effective at a temperature peculiar to it. Although an increase in temperature may accelerate a reaction, enzymes are unstable when heated. The catalytic activity of an enzyme is determined primarily by the enzyme's amino-acid sequence and by the tertiary structure - that is, the three-dimensional folded structure - of the macromolecule.

Many enzymes require the presence of another ion or a molecule, called a co factor, in order to function. As a rule, enzymes do not attack living cells. As soon as a cell dies, however, it is rapidly digested by enzymes that break down protein. The resistance of the living cell is due to the enzyme's inability to pass through the membrane of the cell as long as the cell lives. When the cell dies, its membrane becomes permeable, and the enzyme can then enter the cell and destroy the protein within it. Some cells also contain enzyme inhibitors, known as anti enzymes, which prevent the action of an enzyme upon a substrate.

Useful Rennin facts. Milk coagulates or sets when its protein molecules stick together to form solid lumps. This is a natur at process which takes roughly 2 to 3 days. An enzyme called rennin speeds this reaction up so that it only takes a few minutes... Rennin is found in the stomachs of baby mammals that solely drink milk. Setting the milk quickly in the stomach allows time for digestion.

What factors affect the rate at which rennin coagulates (sets) milk? Prediction following research predict that the higher the concentration? The greater the amount of rennin added the faster the milk will coagulate. This theory is based on the fact that the rennin generally sticks the protein molecules together to form lumps, which means that the higher the ratio of rennin to protein molecules the fact the milk will set. Variables There aren't many things to vary. Temperature.

Concentration of rennin. Concentration of milk Equipment 1.5 test tubes 2.1 test tube rack 3.3 syringes (one for milk, one for rennin and one for water) 4. Water bath (set at 37 degrees) 5. Water 6. Rennin 7.

Milk 8. Stop watch 9. Thermometer Method Do a trial test of the two extremes you are planning to test. In my case the combination of substances is 0.8 ml of water, 0.2 ml of Rennin and 2 ml of milk and 0.2 ml of water, 0.8 ml of Rennin and 2 ml of milk. (When doing the trial experiment agree on a type of thickness e.g. Will it have started to separate, will it stay in the bottom of the tube when turned upside down. 1) Gather you equipment together placing you test tubes in the racks 2) Use three separate syringes to gather your substances.

3) First put 2 ml of milk in each test tube 4) If you haven't already prepare a water bath and set it at 37 degrees 5) When the bath is at the right temperature place all the test tube in it to get the milk to the right temperature (have the tubes numbered 1-5 and put a thermometer in to test tube 1.6) Fill the other two syringes. One with 0.2 ml of Rennin and 0.8 ml of water. 7) When test tube one has reached 37 degrees simultaneously add the water and rennin and start the stopwatch. (At this point two people are necessary.) 8) When the milk has set to the thickness you agreed on earlier during the trial experiment remove the test tube and record the time.

9) Get one person to wash out the test tube whilst the other person fills the syringes with 0, 4 ml Rennin and 0.6 m of milk. 10) Repeat steps seven and eight. 11) Wash out the test tube and do the test again using these combinations. (each time recording the time and washing out the test tube.) Water (ml) Rennin (ml) 0.2 0.80. 0 1.012) Once you have tested and recorded each combination you have finished the test. However if you want an accurate average I advise you to repeat the test three times. Fair test To ensure a fair test I did a number of things...

I made sure that the milk was always 37 degrees. I did not stir any of the combinations. I found it hard to find a recording point but I did my best to make sure it was the same for each test... I made sure that my measurement of each liquid was accurate. I continuously checked to make sure that the temperature of the water bath was always 37 degrees.

The same person timed and recorded each time, just as the same person decided when to stop the test / stopwatch... Also I will add water the each combination to make the volume of each test the same. Results of the rennin experiment performed by myself (Kelera Godwin) and my science partner Krystal Osmond. How long does it take for milk to coagulate?

My prediction was correct. Although I did my best to make it fair I do not think that the test results were as accurate as I would have liked. My results show that the more rennin there was the faster the reaction took place. Evaluation I found this experiment successful because the results coincide with my prediction.

There were a few things that I was unhappy about starting with adding water. I wanted it to be fair and to have an equal amount of volume per test tube. Although I am not sure weather this affected the experiment by watering down the rennin. I collected the results to the best of my ability although I found it difficult to determine a set point at which to stop the experiment. I believe that the results were accurate therefore the averages and table are reasonably accurate. I do not think that I received and anomalous results however I am concerned about the varying amounts in the recorded time of the combination: 0.8 ml water, 0.2 ml Rennin.

If I were to extend this experiment to find out more about how rennin works I would do the experiment using temperature as another variable. If I were to do this as an experiment I would predict that the rennin, milk combination would not work in very high or very low temperatures. If I were to improve my experiment I would ask to have more equipment eg: 1 stopwatch would only allow you to do each test one at a time unless you started one test at 0 seconds and started the second at something like 30 seconds. (S e t s) M i l k Write up by Kelera Godwin.