S P E E D I N G U P C H E M I C A L R E AC T I O N S

Transcription

1 ENZYMES S P E E D I N G U P C H E M I C A L R E AC T I O N S

2 TEKS 9C: Students will identify and investigate the role of enzymes

3

4 WHAT ARE ENZYMES? Enzymes are proteins (what is their monomer?) These proteins are used by the cell to speed up and regulate chemical reactions Enzymes can also be called catalysts They remain unchanged by the reaction

5 HOW DO ENZYMES WORK? Enzymes lower the activation energy of a reaction Activation energy = the minimum amount of energy needed for a chemical reaction to occur They do this by adding some of their own energy to the reaction If there were no enzymes, many reactions would require higher temperatures to occur

6 PLEASE NOTE Enzymes do NOT increase how much product is made (just how quickly and easily it is made) Enzymes do NOT get used up in the reaction (therefore, they can continue to catalyze reactions over and over again)

7 HOW DO ENZYMES WORK?

8 ENZYME STRUCTURE Enzymes are proteins with a 3-dimentional shape caused by the folding of the protein The specific shape of the enzyme determines which substrate it works with Substrate = substances acted on by enzymes Most enzymes end with -ase Lipase acts of lipids Maltase acts on maltose Protease acts on proteins Lactase acts on lactose All enzymes end with ase.so if I say Studentase what type of enzyme is this?

9 ACTIVE SITE The substrate is temporarily bound to its enzyme at the active site Only substrates that are the same size and shape as the active site can bind to an enzyme (specificity) The enzyme may change shape slightly to accommodate the substrate (induced fit) Induced fit helps substrates react to form product(s)

10 ACTIVE SITE

11

12 TWO JOBS Enzymes can break down substrates into their component parts (what is this called? Example?) OR Enzymes can put multiple substrates together into one larger molecule (what is this called? Example?)

13 CHAINS Enzymes often work as a series of reactions that turn substrates into products If one step in the chain doesn t work, the product cannot be made

14 DENATURE If enzyme #4 in the image above stopped functioning correctly, what would happen? Would the green substrate be turned into the orange substrate? Would the orange substrate be turned into the yellow substrate? Would the yellow substrate be turned into the purple substrate? Would the purple substrate be turned into the blue substrate? Would the blue substrate be turned into the red substrate? Which substrate would you have the most of?

15 DENATURE Enzymes work within a narrow range of environmental factors Temperature, ph, and concentration must be correct if an enzyme is to function properly If the environment is not conducive to enzyme activity, the enzyme may fall apart. This distorts the shape of the active site, which means the substrate cannot attach to the enzyme, and the enzyme cannot do its job If the enzyme comes apart and its active site no longer has the correct shape, it is said to be denatured

16 FACTORS AFFECTING ACTIVITY Temperature The temperature where the enzyme functions most effectively is called the optimal temperature If the temperature is lowered too much, enzyme activity will slow down and eventually stop If the temperature is raised too far above the optimal temperature, the enzyme will become denatured and stop functioning

17 FACTORS AFFECTING ACTIVITY Temperature

18 FACTORS AFFECTING ACTIVITY Temperature 1. What is the optimal temperature for enzyme A? 2. What is the optimal temperature for enzyme B? 3. Knowing that room temperature is approximately 22 Celsius, which enzyme would work best?

19 FACTORS AFFECTING ACTIVITY ph ph tells you how acidic (or basic) a solution is ph is a measure of the number/concentration of hydrogen ions in solution [H + ] ph = 7 is neutral and occurs when [H + ] = [OH - ] ph lower than 7 is acidic and occurs when [H + ] > [OH - ] ph higher than 7 is basic and occurs when [H + ] < [OH - ] If the ph is lowered or raised outside optimal, the enzyme will denature & stop functioning

20 FACTORS AFFECTING ACTIVITY ph

21 FACTORS AFFECTING ACTIVITY ph

22 FACTORS AFFECTING ACTIVITY ph 1. What is the optimal ph for the enzyme found in your stomach? Gastric Protease 2. What is the optimal ph for the enzyme found in your intestines? Intestinal Protease 3. What organic substances are both of these enzymes digesting?

23 FACTORS AFFECTING ACTIVITY Concentration Concentration = amount of enzyme and/or substrate present The larger the concentration of the enzyme, the faster the rate of the reaction (up to a point) Saturation point is the point at which no more substance can be absorbed/worked on

24 FACTORS AFFECTING ACTIVITY Concentration

25 FACTORS AFFECTING ACTIVITY Rate of the reaction depending on the concentration of the substrate (with or without enzymes)

26 INHIBITION Enzyme inhibitor: a molecule that binds to an enzyme and decreases its activity (2 types) Competitive: the inhibitor is competing with the substrate for access to the active site Non-competitive: the inhibitor binds to the enzyme at the allosteric site (which is different than the active site). This binding changes the shape of the active site, making it impossible for the substrate to bind

27 INHIBITION