1. 2.5 Enzymes: Enzymes control the metabolism of the cell. Nature of science: Experimental design—accurate, quantitative measurements in enzyme experiments require replicates to ensure reliability. Understandings: Enzymes have an active site to which specific substrates bind. Enzyme catalysis involves molecular motion and the collision of substrates with the active site. Temperature, pH and substrate concentration affect the rate of activity of enzymes. Enzymes can be denatured. Applications and skills:  Application: Methods of production of lactose-free milk and its advantages. Lactase can be immobilized in alginate beads and experiments can then be carried out in which the lactose in milk is hydrolysed. PRACTICAL Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes. Students should be able to sketch graphs to show the expected effects of temperature, pH and substrate concentration on the activity of enzymes. They should be able to explain the patterns or trends apparent in these graphs. Theory of knowledge: Development of some techniques benefits particular human populations more than others. For example, the development of lactose-free milk available in Europe and North America would have greater benefit in Africa/Asia where lactose intolerance is more prevalent. The development of techniques requires financial investment. Should knowledge be shared when techniques developed in one part of the world are more applicable in another? Topic 2: Molecular biology (21 hours)

2. Biology Journal 9/19/2014 What is a rate? What is the rate we are measuring in this lab?

3. Biology Journal 9/18/2014 a.What does a broken toothpick represent? b.What represents the enzyme? c.You need 3 to 5 people in your group. What does each one do?

4. Describe the lock and key model of enzyme function. Enzymes are specific to one (although sometimes multiple) substrate. How? 1. Structurally: the 3D shape of the active site matches the substrate 2. Chemically: the polar / nonpolar parts of the active match the substrate Biology Journal 9/22/2014

5. Some Jobs for this Experiment: 1.Enzyme: person who breaks the toothpicks 2.Organizer: person who sets up the trial 3.Cleaner: makes sure all materials are returned / disposed of after each trial 4.Timer: keeps track of and announces time 5.Counter: keeps track of number of broken toothpicks during trial 6.Recorder: writes down data

6. There are 3 Trials in this Experiment… A.Rate and time 1.Start with 100 toothpicks 2.Lasts 180 seconds (3 minutes) 3.Count number of toothpicks broken at 10, 20, 30, 60, 120, 180 seconds B.Rate and concentration 1.Start with different numbers of toothpicks (10, 20, 30, 40, 50, 60, 70, 80, 90, 100) and 100 paperclips. 2.Lasts 20 seconds only 3.Count number of toothpicks broken at end C.Rate and temperature 1.Start with 10 toothpicks 2.Time is now dependent variable (you measure how long it takes the enzyme to break all 10 toothpicks)

7. Biology Journal 9/17/2014 a.What kind of reaction is shown? b.Write out the reaction as words: fructose + _______ → ________ + _______ c. Which are the reactants? d. Which are the products? + + → H2OH2O

8. Biology Journal 9/5/2013 a. What kind of reaction? Anabolic Condensation b. Write out the reaction as words: below c. Which are the reactants? fructose, glucose d. Which are the products? sucrose, water + + → H2OH2O fructose + glucose → sucrose + water Today we will learn how enzymes make this happen!

9. Biology Journal 9/17/2014 What is a genome? What is a proteome? Do you think all humans have mostly the same genome, or naw? Do you think all humans have mostly the same proteome, or naw? Where could be some places that our biological differences come from?

10. Humans share over 99% the same DNA. DNA codes for proteins, so our proteins are over 99% identical as well. Our differences come from 2 things: mutations, and the recombination of genes during every sexual reproduction!

11. What is a catalyst? Catalysts speed up chemical reactions (and they’re not used up by the reaction)Review!

12. 2.5 Enzymes Hair is a protein called KeratinEnzymes speed things up.

13. Enzymes: Specially shaped proteins that are catalysts. Enzymes are specific, like a lock and key. Enzymes make reactions fast! (but they usually don’t blow up; that’d be bad for a living thing)

14. TIME Energy in Reactants/Products Start (reactants) Intermediaries Reaction Complete (products) Activation Energy Without enzyme With enzyme Energy-Time Graph for a Chemical Reaction

15. Activation energy is the energy which must be put into reactants to break some bonds to get a reaction started Enzymes lower activation energy, making reactions happen faster. These reactants (TNT) really want to be the products (a bunch of gasses). It just needs the activation energy to do the reaction…. Where does the activation energy come from? An Explosive Example…

16. Substrate Substrate: the reactant that goes into the enzyme Active site Active site: where the substrate bonds on the enzyme Products Products: what the substrate turns into

17. Enzymes do not run out. They keep making the product over and over. How is this chemical reaction different from the previous one?

18. Enzymes are specific Each enzyme acts on only one (or a limited number) of substrates Each enzyme will only act on substrates that will fit into its active site Enzyme Active site Substrate: shape is complementary to shape of active site Each enzyme catalyses very few reactions

19. Active site fits around substrate Active site no longer fits round substrate Treat with high temperature… … or strong acid/alkali Like any protein, an enzyme can denature (lose its shape and thus stop working).

20. Enzymes end in “-ase” (almost always) What do you think these enzymes do? ProteaseLactaseLipase Cellulose synthase Glucose phosphotransferase

21. Sketch this picture into your journal and label the parts. Describe what kind of reaction is occurring in as much detail as you can.

22. A = Substrate B = Enzyme C = Active site D = Enzyme-substrate complex E = Products This is the enzyme-catalyzed decomposition of A into E’s.

23. Read the entire toothpickase lab. Re-read until you understand the directions completely! Do all of the parts of the lab in your graph notebook through “Data: lab group data”. Specifically: 1.Write the title 2.Do the pre-lab questions 3.Write the first heading 4.Write the “Procedure” for this part 5.Write “Data: class data” and prepare a data table that you will have ready to fill in tomorrow! Your Assignment:

24. Enzymes are an example of a kind of molecule called a protein. Tissues like hair, muscle, and skin are also made out of this polymer; the polymer is composed of monomers called amino acids. Enzymes are an example of a kind of molecule called a ______. Tissues like hair, muscle, and skin are also made out of this polymer; the polymer is composed of monomers called ___________.

25. Enzymes (almost) always end in what 3 letters? ASE

26. Do all enzymes catalyze (speed up) decomposition reactions? No! What kind of reaction is this?

27. Are enzymes consumed in a chemical reaction? What happens to the enzyme in this picture? What happens to the product?

28. Describe the lock and key model of enzyme function. Enzymes are specific to one (although sometimes multiple) substrate. How? 1. Structurally: the 3D shape of the active site matches the substrate 2. Chemically: the polar / nonpolar parts of the active match the substrate

29. Define what it means for a protein to denature.

30. All enzymes have an optimal temperature and pH.

32. TIME Energy in Reactants/Products Start (reactants) Intermediaries Reaction Complete (products) Activation Energy Without enzyme With enzyme What is activation energy? How does an enzyme “catalyse” a reaction?

33. What is lactose intolerance?

34. A person with lactose intolerance is not producing the enzyme lactase. Lactase is the enzyme that catalyzes the catabolic hydrolysis of lactose into galactose and glucose.

35. Percentage of Population with Lactose Intolerance Where are you from? The chances of having lactose intolerance are genetically tied to cultural and historical uses of animal milk as a food source. For example, in Northern European culture cow milk was used as a food source for many centuries; in South America, it was not.

36. Aspergillus niger is also known as black mold. You’ve most likely seen it before. To cope with lactose intolerance… 1.Take a lactase supplement, made by a genetically engineered fungus. 2.Drink lactose-free milk.

37. Lactose-free milk can be made by: 1. Adding lactase to milk. 2. Running milk through an apparatus with immobilized lactase.

38. Scientific Method

39. What is the dependent and independent variables in this experiment? What could be controls?

40. Independent Variable: The “cause” that is more directly controlled or measured. Graphed on x axis. Dependent Variable: The “effect” you measure. Graphed on y axis. “Independent causes Dependent” “The dependent variable depends on the independent variable” Controls: Anything that could effect the outcome of the dependent variable. Some controls can be “controlled” (purposely kept constant), but some can only be acknowledged as variables impacting the data.

41. Independent Variable