Enzymes and Reaction Rates Chemical reactions occur when molecules interact and chemical bonds between them are formed or broken. People who don't make enough lactase have trouble digesting milk products and are lactose intolerant.
Children are usually lactose tolerant, but many people lose the ability to digest milk sugars as they grow older. Your probability of being lactose intolerant is correlated with whether your ancestors raised milk cows. The commercial product, Lactaid, contains lactase. Lactase catalyzes the conversion of lactose to glucose and galactose. Materials: Water Milk Lactaid tablets available from grocery or drug store Glucose test strips available from drug store Table Sugar Solution Preparation: Lactose solution: Milk, about ml.
Sucrose Solution: Add 5 grams of sugar to ml of water. Stir until the sugar has dissolved. Enzyme Solution: Add 1 lactase tablet to ml of water. Stir until the tablet has dissolved.
Denatured Enzyme Solution: Place 20 ml of Enzyme Solution into a glass container such as a canning jar. Add ml of water, and then seal the lid. Add the canning jar to a pot of water, and bring the pot of water to a boil. Let the solution cool to room temperature. Procedures: Divide the lactose solution and sucrose solution into two containers each.
Be sure to label the containers. Add the enzyme solution to one, and the denatured enzyme solution to the other. Dip an unused glucose test strip into each container and record whether glucose is detected in the table below.
Glucose Detected? What must have happened? What must have happened to the enzyme solution when boiled? Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.
Many enzymes change shape when substrates bind. Some RNA molecules called ribozymes can also be enzymes. These are usually found in the nuclear region of cells and catalyze the splitting of RNA molecules. Enzymes are catalysts that breakdown or synthesize more complex chemical compounds. They allow chemical reactions to occur fast enough to support life. Enzymes speed up the rate of chemical reactions because they lower the energy of activation, the energy that must be supplied in order for molecules to react with one another.
Enzymes are very efficient. An enzyme generally can typically catalyze between 1 and 10, molecules of substrate per second. Enzymes are only present in small amounts in the cell since they are not altered during their reactions. Generally there is one specific enzyme for each specific chemical reaction. Some relationships between bacterial enzymes and the use of disinfectants and extremes of temperature to control bacteria. Learning Objectives Define or describe the following: metabolism catabolic reaction anabolic reaction enzyme substrate apoenzyme haloenzyme cofactor coenzyme State how enzymes are able to speed up the rate of chemical reactions.
Briefly describe a generalized enzyme-substrate reaction, state the function of an enzyme's active site, and describe how an enzyme is able to speed up chemical reactions. State four characteristics of enzymes. State how the following affect the rate of an enzyme reaction. State how high temperature and low temperature exert their effect on bacteria.
Characteristics of Enzymes Chemically, enzymes are generally globular proteins.
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