1. Ch. 6.3, 6.4 & 6.5 Energy & Enzymes

2. _______________________ required to start the reaction energy level of reactants energy content of molecules energy level of products progress of reaction An _____________________ reaction Sparks ignite gas high low 6.2 All Chemical Reactions Require Activation Energy to Begin https://www.youtube.com/watch?v=p-27I_osoaw&feature=relatedhttps://www.youtube.com/watch?v=p-27I_osoaw&feature=related (History Lesson on Endo and Exo) http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/chemreac/energychangesrev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/chemreac/energychangesrev1.shtml (ex of rxn)

3. (b) An exergonic reaction

4. 6.3 How is Energy Transported Within Cells  organisms powered by chemical energy supplied by ____________ breakdown of glucose  energy transferred to _____________________________(i.e. ATP)  charged by exergonic rxns and drive endergonic rxns (i.e. rechargeable batteries  ATP recycled approx. 1,400X/day (marathon runner uses a lb. of ATP/min Dehydration synthesis uses energy when making ATP from ADP.

5.  _________________________– energy carrier molecules that ______________energetic electrons & H+ ions  donate high-energy electrons to other molecules  NADH, FADH 2

6. Coupled Reactions Link Exergonic with Endergonic Reactions  _____________reaction - exergonic rxns provide energy needed to __________endergonic rxns ___________________ - plants use sunlight (____gonic) to drive _______gonic synthesis of high-energy glucose molecules from lower-energy reactants (CO 2 + H 2 O) ________________ – organisms break down glucose into CO 2 + H 2 O (_____gonic) to drive synthesis of proteins, amino acids (_____gonic)  energy is always __________________every time it is transformed  energy released (exergonic) must always exceed energy needed (endergonic) https://www.youtube.com/watch?v=7IqgrcBkGRU

7.  activation energy determines the ________ at which a reaction occurs https://www.youtube.com/watch?v=VbIaK6PLrRM https://www.youtube.com/watch?v=VbIaK6PLrRM Blue = exothermic Green = endothermic  some important chemical reactions are too slow or have a high activation energy 6.4 How Do Enzymes Promote Biochemical Reactions? reactants exothermic

8.  _____________ – substances that __________rates of chemical reactions w/o being used up or permanently altered https://www.youtube.com/watch?v=hNl5WYSM5DEhttps://www.youtube.com/watch?v=hNl5WYSM5DE (Elephant Toothpaste) https://www.youtube.com/watch?v=v9ju2rZ8YmMhttps://www.youtube.com/watch?v=v9ju2rZ8YmM (how catalytic converters work – 10 min)

9. Enzymes are Biological Catalysts  not advantageous to speed up dozens of rxns at once; so it is a _________________  _______________– natural catalysts (mostly proteins)  each catalyzes only a few types of rxns (most only catalyze 1 with specific molecules)  exergonic & endergonic rxns can be catalyzed  ATP synthase + ATPase https:// www.youtube.com/watch?v=W3KxU63gcF4https:// www.youtube.com/watch?v=W3KxU63gcF4 (ATP Synthase)

10. Structure of Enzymes Allows Them to Catalyze Specific Reactions  ____________ of enzyme _______________ its ____________ (just like proteins)  structure – determined by a.a. sequence/twisted/folded  shape and charges of a.a. that form active site determines what molecules can enter (amylase  starch not cellulose; pepsin & trypsin)  some catalyze tens of thousands of rxns/sec and some act much slower https://www.youtube.com/watch?v=lfuOQZJ_MIM (firefly) https://www.youtube.com/watch?v=lfuOQZJ_MIM

11. Enzymes, Like All Catalysts, Lower Activation Energy  reactions occur in_____; each step catalyzed by different enzymes  ____________activation energy overall  reaction can occur at body temp https://www.youtube.com/watch?v=r1ryDVgx0zw https://www.youtube.com/watch?v=tI69AVRW0DUhttps://www.youtube.com/watch?v=tI69AVRW0DU (related to digestion)

12. How Are Enzymes Regulated?  metabolism – sum of all the ________________________in a cell  metabolic pathways – reactions that are linked together - ________________ step acts as the ________________________ step i.e. _______________ (synthesis of high energy molecules i.e. glucose) i.e. glycolysis (begins breakdown of glucose) Initial reactant Intermediates End products PATHWAY 1 PATHWAY 2 enzyme 1 enzyme 2 enzyme 3 enzyme 4 enzyme 5 enzyme 6 https://www.youtube.com/watch?v=l_vvz5fD00Mhttps://www.youtube.com/watch?v=l_vvz5fD00M – photo & resp.

13.  Cells must regulate metabolic pathways by controlling ____ produced. a) type of enzymes b) quantity of enzymes c) activity levels of enzymes  for a given ____________ of enzyme, as substrate levels increase, the rxn rate ______________ until active sites of all enzymes are being continuously occupied by new substrate

14.  ________that code for enzymes can turn _____________ - marathon runners & high-carb meals b4 competitions -glucose enters blood & triggers metabolic rxns (i.e. pancreas releases insulin) -insulin turns on genes that code for 1 st enzyme in pathway that breaks down glucose  Some enzymes only synthesized at ________________ in organisms life (i.e. lactase)  some enzymes are synthesized in _______________ and then activated when needed (i.e. protein digesting pepsin & trypsin – work best in acidic conditions) http://lgfl.skoool.co.uk/content/keystage3/biology/pc/learningsteps/PAELC/launch.html

15. Enzyme Activity May be Controlled by Competitive or Noncompetitive Inhibition  Reactions ______________ by competitive inhibition and noncompetitive inhibition to prevent 1) substrates from being _________ and 2) producing _________________ product  ____________________ inhibition: substance that is not the enzyme’s normal substrate can _________________to active site of enzyme (competing for a spot) - structural similarities i.e. _________________________ (block active site of acetylcholinesterase; excess acetylcholine overstimulates muscles causing paralysis) https://www.youtube.com/watch?v=-gIqZ8IxctE i.e. _______________________  inhibits synthesis of bacteria cell walls; ________________________________  inhibits synthesis of molecules that contribute to swelling, pain, fever.

16.  ____________________ inhibition: molecule binds to a site on enzyme different from active site; ___________________; enzyme less able to catalyze rxn  https://www.youtube.com/watch?v=PILzvT3spCQ (short comparison) https://www.youtube.com/watch?v=PILzvT3spCQ

17.  _____________________: _______________________ inhibition where enzymes ___________ easily between 2 different ________ that either activate or inhibit the enzyme (i.e. ADP) https://www.youtube.com/watch?v=d5fDEUhjo-M  ___________________: form of ________________ regulation; causes metabolic pathways to ______________________________ when its concentration reaches an optimal level (thermostat) https://www.youtube.com/watch?v=DHZtOKyMPRYhttps://www.youtube.com/watch?v=DHZtOKyMPRY (feedback inhibition) As levels of isoleucine rise, isoleucine binds to the regulatory site on enzyme 1, inhibiting it intermediates enzyme 1 enzyme 2 enzyme 3 enzyme 4 enzyme 5 enzyme 1 isoleucine (end product) threonine (initial reactant)

18. Activity of Enzymes is Influenced by Their ____________________  enzymes have a narrow range of conditions (_________________) in which they function optimally (H-bonds btwn polar a.a.)  _______________: when enzymes lose 3-D structure required to function properly  human cellular enzymes work best around pH 7.4; human digestive enzymes work best around pH 2  __________________ affects rate of enzyme catalyzed reactions (_____________ by _______________ temps; ________________ by ________________ temps) http://lgfl.skoool.co.uk/viewdetails_ks3.aspx?id=452

19. For pepsin, maximum activity occurs at about pH 2 For most cellular enzymes, maximum activity occurs at about pH 7.4 For trypsin, maximum activity occurs at about pH 8 rate of reaction Effect of pH on enzyme activity pH 10 65432 10 7 89 fast slow

20. For most human enzymes, maximum activity occurs at about 98.6  F (37  C) rate of reaction fast slow Effect of temperature on enzyme activity temperature 60 (  C) 04020 140 (  F) 3268 104