ENERGY & ENZYMES

1. ENERGY & ENZYMES

2. LIFE PROCESSES REQUIREENERGY • Energy = the ability to move or change matter.

3. What are some forms of energy? • Light • Heat • Chemical • Electrical

4. From food webs to the life of a cell energy energy energy

5. organic molecules→ATP & organic molecules solar energy→ATP& organic molecules organic molecules→ATP & organic molecules sun Flow of energy through life • Life is built on chemical reactions • transforming energy from one form to another

6. Chemical Reactions • Process in which bonds between atoms are broken, and new ones are formed. • This produces one or more different substances.

7. Chemical Equations Reactants: The starting materials for a chemical reaction. Products: The substances that form after the reaction. Follow a specific format • ReactantsProducts • NaCl Na+ + Cl-

8. Metabolism All of the chemical reactions that occur within an organism.

9. Metabolism • Chemical reactions of life • Bond must form between molecules • Occurs through dehydration synthesis • Dehydration synthesis: A chemical reaction that buildsup molecules by losingwater molecules. • Anabolic reactions – Building up molecules from smaller units - Requires an input of energy • That’s why they’re calledanabolicsteroids!

10. Metabolism • Bonds also must break between molecules • Occurs through hydrolysis • Hydrolysis: chemical reaction that breaks down molecules by adding water molecules e.g. starch into glucose • Digestion • Catabolic reactions – Breaking down of molecules into smaller units

12. digesting molecules= LESS organization=lower energy state building molecules= MORE organization=higher energy state Chemical reactions & energy • Some chemical reactions release energy • exergonic • Some chemical reactions require inputof energy • endergonic

14. Energy is needed to start a chemical reactionENERGY • Activation Energy: The energy needed to start a chemical reaction.

15. Enzymes help reactions occur • Enzymes: substances that increase the speed of chemical reactions. • http://www.youtube.com/watch?v=XTUm-75-PL4

16. Enzymes: • are Proteins • are Catalysts • are in YOUR cells catalyzing reactions RIGHT NOW • Help you maintain homeostasis • Are specifically shaped by type • Work on substrates • Substrate: substance upon which enzymes work • Have active sites (part the substrate fits into)

17. Some common enzymes: • Amylase • Catalase • Sucrase • DNA Polymerase • Lipase • Protease

18. Naming conventions • Enzymes named for reaction they catalyze • sucrase breaks down sucrose • proteases break down proteins • lipases break down lipids • DNA polymerase builds DNA • adds nucleotides to DNA strand • pepsin breaks down proteins (polypeptides)

19. Activation Energy with and without an enzyme

20. How does an enzyme work? • Step 1: Enzyme attaches to its specific substrate (sucrase attaches with sucrose) • Step 2: At the active site, the enzyme and the substrate interact in a way that reduces activation energy of the reaction • Step 3: The reaction is complete when products form. The enzyme is now free and goes an acts on a new substrate.

21. Lock and Key model • Simplistic model of enzyme action • substrate fits into 3-D structure of enzyme’ active site • H bonds between substrate & enzyme • like “key fits into lock”

22. Some things can make enzymes work FASTER or NOT AT ALL • Temperature: Enzymes work at optimal temperatures. If the temperature is too high or too low, it may change the shape of the enzyme so it won’t work. • pH: Values outside of the preferred range of enzymes may cause bonds to break and then the enzyme can’t work.

23. What’shappening here?! 37° Temperature reaction rate temperature

24. 37°C 70°C Enzymes and temperature • Different enzymes function in different organisms in different environments hot springbacteria enzyme human enzyme reaction rate temperature (158°F)

25. What’shappening here?! pH pepsin trypsin pepsin reaction rate trypsin 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH