1. Chapter 3

2. * Enzymes can catalyze rxns to break up a substrate into 2 new products of combine two substrates into 1 new product * Parts of rxn: * Enzyme * Substrates * Enzyme-substrate complex * Enzyme product complex * Product(s) * R-groups on enzyme interact with substrates, forming or breaking bonds between/on substrate(s) * Enzymes remain UNCHANGES after product is formed and leaves active site * Enzyme available to catalyze rxn for another substrate * Rapid process (substrate binding to active site, products forming and products leaving active site)

4. * Catalase * Enzyme that breaks up hydrogen peroxide H2O2 (toxic) into H2O and O2 gas * rxn happens at rate of 10 million molecules per second * Lysozyme * Enzyme that defends body against bacteria * Saliva, sweat, tears * Breaks down polysaccharide chains in bacterial cell wall

5. * Extra energy required by chemical reactions to convert substrates into products * E required to start making products * Higher activation energy = takes longer to make products (increase rate of chemical reaction) * Lower/less activation energy = less time to start making products (decrease rate of chemical reaction)

9. * Enzymes speed up chemical reactions that take place in cells * They DECREASE ACTIVATION ENRGY * The energy needed to get the reaction started (or energy needed to start making product)

10. * Heat helps INCREASE rate of chemical reaction by causing molecules to collide with each other more rapidly, thus reaction * Increase heat = increase rate at which reactants collide with each other, thus increasing the rate at which a product is made * Body temp. 37*C * Warm but not enough heat to make biochemical rxns in living organisms happen fast enough * If we raise body temp. to much, body’s proteins denature = not good * How do we speed up rate at which products are made without increasing temperature? * Use ENZYMES  allow reactions to occur quickly without increasing temperature * Enzymes required * Enzymes DECREASE Activation energy of Rxns * Enzyme HOLD substrate(s) in place in position to enable molecules to react Example: Benedicts Test for Reducing Sugar (monosaccharaides and disaccharides) Benedicts solution + sugar will not react In order to see rxn, we must HEAT up Benedit & sugar solution  reaction occurs and we see color change

12. * All biological materials contain catalase * Used to break up the toxic H2O2 (hydrogen peroxide produced by our cells) into oxygen gas and water * Measure production of oxygen gas * Found in saliva * Breaks down starch into maltose * Use iodine to measure concentration of starch * Iodine is brown * When in contact with starch, turns dark blue/black * Measure intensity of color for qualitative results * Measure time to change for quantitative results

13. * Measure rate of formation of product * Catalase releases oxygen gas * We can measure the volume of oxygen gas produced (or number of oxygen gas bubble) * Measure rate of disappearance of substrate * We can test for Starch (iodine solution test) blue-black color * Presence of Starch = blue-black color * When AMYLASE is added, it will start breaking down starch * When starch breaks down = less starch = less blue-black color * Measure time it takes to blue-black color to disappear

14. * Explain * Use scientific knowledge to explain WHY the relationship is found between your independent and dependent variable * Describe * Describe results  use table (best to use graph) * How to describe results shown on graph: * Begin by describing overall trend * Look for changes in gradient on graph and describe these changes * Quote figures from the graph * Pick specific points of interest, such as where gradient changes occur * State x and y coordinates * Do not use phrases that suggest something is occurring over time if time is not one the graph * Phrases to Avoid if time is not on your x-axis * At first * More quickly * Slower * rapidly

16. * Rxns begin swiftly (exponentially at first, steep slope) * As soon as enzyme is mixed with substrate, product begins forming (increase in concentration of product) * As rxn progresses, rate of product formation slows down (slope will flatten out, horizontal) * Rxn gets slower until it stops * Large # of substrate molecules; every enzyme has a substrate molecule in it * Rate of rxn will depend on # of enzymes available and how fast they work they can turn substrates into products * As more and more substrates are converted into products, there are fewer substrate molecules available to bind to active site of enzymes * Enzymes are now “WAITING” for substrate molecules to hit their active sites * Eventually, there are no more substrate molecules left to attach to enzymes, thus no more products being made, enzymes are empty and the reaction is over “Describe” “Explain”

17. * Curve steepest at beginning * Initial rate of Rxn = steepest part of the curve * 2 ways to measure to measure initial rate of reaction: 1. Calculate the SLOPE of a tangent to the curve AS CLOSE TO TIME 0 as possible 2. Read the amount of product produced at the first 30 s (if this is steepest part of graph) * Sometimes it is hard to measure the rate at which a product is formed * think about mixtures in which the products and reactants are indistinguishable * Alternate way to measure rate of reaction: * Measure rate at which SUBSTRATE disappears from reaction mixture * (measuring rate at which amylase breaks up starch) 1. Mix enzyme and substrate 2. Take samples at KNOWN times 3. Use indicator that measure intensity (thus concentration of substrate) 4. As concentration of substrate decreases, color intensity will decrease 5. Plot on graph “amount of remaining substrate vs. time” 6. Calculate initial rate of reaction as before

18. 1. Draw a tangent to the curve at that point, making sure it is at least HALF as long as the line of the graph 2. Draw a right angle on the tangent 3. Calculate the gradient using the lengths of the triangle sides x 2 and y 2 : * Gradient = y 2 x 2

22. * Enzyme Concentration * Substrate Concentration * Temperature * pH * Inhibitors