This experiment is investigating one of the factors which affects the rate of fermentation of yeast.

Several factors affect the rate of reaction:

 Increasing the concentration. (See the lock and key theory.) If the substrate (glucose) is increased, then there would be more keys for the locks, therefore an increase in reactant concentration leads to an increase in reaction rate.

 The surface area, the bigger the surface area, the faster the reaction time is, as the reactant can reach more parts.

 The temperature, an increase in temperature leads to an increase in reactant rate. Generally, as the temperature is increased, the particles get more energy, so they bump into one another more, therefore speeding up the reaction time. This is called the collision theory, which I will discuss in greater depth later.

 Whether or not there is a catalyst. A catalyst speeds up the rate of reaction and remains chemically unchanged by the end of the experiment. A catalyst lowers the activation energy. This is the energy needed to start a reaction.

The variable that I have decided to change is the temperature. I have deci

Enzymes have an active site. This is a special shape, in which a specific molecule can fit, e.g. starch fits into the active site of amylase. This is called the lock and key theory. A lock is a special shape and only a key of the required shape can fit and open the lock. The enzyme is the lock and the substrate is the key. In my investigation, the substrate is the glucose, the key. The lock is the enzyme.

While doing an experiment such as this, it is vital to be safe at all times. You should stand up at all times, making sure that stools are firmly under desks. When the Bunsen burner is not being used, make sure that the orange 'safety flame' is on. Use a heatproof mat and safety gauze.

For my investigation, I will look at secondary sources, from a textbook, encyclopædia, and preliminary work that I have done in class.

I will record my results clearly and accurately, using a table and remembering to put the quantity, units, and repeats in the table.

Most chemical reaction happen faster when the temperature is high. At higher temperatures molecules move around faster, this makes it easier for them to react together. Usually, a rise of 10 degrees Celsius will double the rate of a chemical reactor. Most of the chemical reactions happening inside a living organism are controlled or catalysed by enzymes.

I will use the following apparatus to get the most accurate results, (remembering to check for zero errors):

The degree of acidity or basicity of a solution, which is expressed as pH, also affects enzymes. As the acidity of a solution changes, e.g. the pH is altered--a point of optimum acidity occurs, at which the enzyme acts most efficiently. Although this pH optimum varies with temperature and is influenced by other constituents of the solution containing the enzyme, it is a characteristic property of enzymes. Because enzymes are sensitive to changes in acidity, most living systems are highly buffered; e.g. they have mechanisms that enable them to maintain a constant acidity. This acidity level, or pH, is about 7 in most organisms. Some bacteria function under moderately acidic or basic conditions; and the digestive enzyme pepsin acts in the acid milieu of the stomach. There is no known organism that can survive in either a very acidic or a very basic environment.

Some common words found in the essay are:
Fermentation Yeast, Analysis Results, BIOLOGICAL CATALYSTS, COLLISION THEORY, Carbon Dioxide, OPTIMUM TEMPERATURE, Delivery Tube, collision theory, reaction rate, rate chemical, carbon dioxide, chemical reaction, enzymes denatured, chemical reactions, enzymes enzymes, special shape, lock enzyme, rate chemical reaction, rate fermentation yeast, lock key theory, eventually reaching zero, 10 degrees celsius,
Approximate Word count = 2560
Approximate Pages = 10 (250 words per page double spaced)