September 13, 2012

1. September 13, 2012 Proteins Sections 2.3, 2.4 in text book Page 19 in guided reading & study guide #23--25

2. Unit test (Wednesday, October 14)Notebook check(Wednesday, October 14)25 points5 pts organized either chronologically or in a way that logically reflects topics (1st ch 1, then ch 18, then ch 2)5 pts mostly complete with at least 75% of the materials issued in class15 points: chapter 2 reading and study guide complete and corrected Materials and announcements online last 2 – 3 weeks at course webpage

3. Take a container of heavy cream and shake it during the lesson. Our purpose is to observe the denaturation of a protein. Heavy cream contains fats as well as proteins that keep these fats dispersed into the water in the milk (a suspension) as long as the proteins have their normal functional shape. If the protein is Denatured, then the fat can not remain suspended & it solidifies. Shaking the protein vigorously breaks bonds that maintain the proteins’ shapes (denatures them) so the proteins can’t carry out their function.

4. Watch these animations about proteins http://wps.aw.com/wps/media/access/Pearson_Default/1663/1703422/login.html Username: mayfieldstudent1 Password: scienceaccount2009 Go to chapter 5 on the top bar, then go to Concept 5.4 Proteins have many structures, resulting in a wide range of functions   Double click to watch Activity: Protein Functions  Double click to watch Activity: Protein Structure   Proteins are polymers made of amino acid monomers • Also called polypeptides because peptide bonds link amino acids • Have optimal 3D shape that controls their function (it depends on the order of the amino acids and on the conditions like pH, temperature) • Are denatured & lose function by breaking (shaking, pH too high or low, too hot or cold, too salty, etc) attractions between amino acid R groups that hold them into their optimal shape at optimal conditions • Include many types of proteins—called the workers of the cell. • Transport proteins that allow materials to move in and out of cells • Receptor proteins that allow cells to use hormones to communicate • Enzymes that catalyze (speed up, lower energy needed) chemical reactions • Hormones and other signal proteins that convey information to other cells • Structural proteins used to build parts of organisms (e.g., collagen in hair)

5. Proteins are polymers of amino acids.Interactions between the R groups (the variable parts—shown in pink & blue on the left picture) of the amino acids causes the protein to fold into a 3D shape necessary for function.When a protein is denatured (loses its shape), it no longer functions. http://www.accessexcellence.org/RC/VL/GG/ecb/ecb_images/04_02_polypeptide_backbone.jpg http://images.google.com/imgres?imgurl=http:/ Campbell’s biology textbook, 7th edition, pearson, prentice hall publishing.

6. #23, page 19 RSGProteins contain what kinds of atoms? • C and H only • C, H, and O • C, H, O and N • C, H, O, N, and P

7. #24, page 19 RSGProteins are polymers of molecules called? • Monosaccharide monomers • Amino acid monomers • Fatty acid monomers • Nucleotide monomers • steroids

8. #25, page 19 RSGWhat is not one of the 4 roles that that proteins usually play in organisms? • Store heredity information & pass it to new cells • Serve as enzymes that speed up reaction • Build structures in the body, like collagen in hair • Serve as receptors and hormones that allow cells to communicate with each other

9. How do we to protect ourselves from food poisoning (infection by bacteria,protists,fungi or viruses)?Cook it: denature proteins by heating atoms (>vibration) to break between R groupsCure it with salt: break ionic bonds between + acidic R groups & – basic R groupsPickle it: +acidic & -basic R groups form ionic bonds w/ bases,acids in pickle solution instead of each otherShake it: break bonds (like making meringues)With proteins—especially enzymes—denatured, the infecting cells can’t carry out chemical reactions or other protein functions, so they die.

10. Structure, operation, and importance of Enzymes http://wps.aw.com/wps/media/access/Pearson_Default/1663/1703422/login.html Username: mayfieldstudent1 Password: scienceaccount2009 Go to chapter 8 on the top bar, then go to Concept 8.4  Enzymes speed up metabolic reactions by lowering energy barriers   Double click to watch Activity: How Enzymes Work   Then, Double click to watch Investigation: How Is the Rate of Enzyme Catalysis Measured? Enzymes are Protein Catalysts: Enzyme are proteins whose 3D shape controls their function. An enzyme speeds up a specific chemical reaction by binding to reactants (substrates) in its active site. Enzymes speed up a reaction by lowering the activation energy (EA) needed to break bonds in substrates In absence of enzymes, EA is obtained by absorbing heat from the surroundings, but high temperatures denature proteins & kill organisms, so enzymes are necessary to let chemical reactions occur at lower temperatures inside cells.

11. Sucrase enzyme catalyzes the chemical reaction that breaks the disaccharide sucrose into its monomers, fructose and glucose: C12H22O11 + H2OC6H12O6 + C6H12O6 reactants products Use the clay to build/show/explain an enzyme that catalyzes reaction of an 8 peg lego block and a 4 peg lego block. Show it functional and denatured!

12. Section 2.4, page 19 RSG #1 What are chemical reactions? For example: A—B + C—D  A—C + B—D (— is a single covalent bond made of electrons shared by 2 atoms) • Breaking old bonds in chemicals and making new ones • Changing the arrangement of electrons in a substance • Creation of new substances • The basis of life • All of the above • None of the above

13. Section 2.4, page 20 RSG#2 top of table What are reactants? A—B + C—D  A—C + B—D • The starting materials in a chemical reaction • The ending materials in a chemical reaction • enzymes • Denatured proteins

14. Section 2.4, page 20 RSG#2 bottom of table What are products? • The starting materials in a chemical reaction • The ending materials in a chemical reaction • enzymes • Denatured proteins

15. Section 2.4, page 20 RSG#3 What always changes during a chemical reaction? A—B + C—D  A—C + B—D (— single covalent bond, electrons shared by 2 atoms) • The physical properties • The chemical properties • Chemical bonds • 1 & 2 • 2 and 3

16. Section 2.4, page 20 RSG#4 What is released or absorbed every time a chemical bond is formed or broken? • atoms • energy

17. Section 2.4, page 20 RSG#5 What do reactions in the body that require energy need to occur? • Very high temperatures • Very high or low pH • Enzymes that can pair the energy needing reaction to an energy releasing reaction (like the breakdown of ATP) and that can lower EA

18. Section 2.4, page 20 RSG#6 Chemists call energy needed to get the reaction started? • Endothermic energy • Exothermic energy • Activation energy • Substrate energy

19. Section 2.4, page 20 RSG#7 What label belongs on the left side of the graph, on the x axis? • Transition state (activated state) • reactants • products

20. Section 2.4, page 20 RSG#7 What label belongs on the right side of the graph, on the x axis? • Transition state (activated state) • reactants • products

21. Section 2.4, page 20 RSG#7 What label belongs on the far right arrow? • Activation energy • Energy absorbed by atoms of the reactants • Energy released by atoms of the products

22. Section 2.4, page 20 RSG#8 A catalyst is? • A chemical that is changed during a chemical reaction • A chemical that speeds up a chemical reaction

23. Section 2.4, page 20 RSG#8 A catalyst is? • A chemical that is changed during a chemical reaction • A chemical that speeds up a chemical reaction

24. Section 2.4, page 20 RSG#9 Proteins that act as biological catalysts are? • Products • Reactants • Enzyme • Receptors

25. Section 2.4, page 20 RSG#10 cells use enzymes to:? • Speed up reactions • Lower activation energy of reactions • Add energy for reactions • 1 and 2 • 2 and 3