Reading Guides for 6.4 and 6.5 PDF

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Professor Rife, received an A...

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6.4 Chemical Reactions (p.124-127) Chemical reactions involved the breaking and forming of bonds. LO 6.4 Explain the type(s) of energy involved in forming and breaking chemical bonds. Terminology: Gibbs free energy (G): the amount of energy available to do work Exergonic: describes reactions with a negative delta G that release energy and proceed spontaneously Endergonic: describes reactions with a positive G that are not spontaneous and so require an input of energy Enthalpy (H): the total amount of energy in a system Entropy (S): the amount of disorder (or the number of possible positions and motions of molecules) in a system Absolute temperature (T): temperature measured on the Kelvin scale Energetic coupling: the driving of a non-spontaneous reaction by a spontaneous reaction

Self-Assessment Questions: 11. For a chemical reaction with a positive value of ΔG, what are the possible relative values for ΔH and TΔS? Is the reaction spontaneous or not? Answer the same questions for a chemical reaction with a negative value of ΔG. 12. How does increasing the temperature affect the change in free energy (ΔG) of a chemical reaction? 13. How can the hydrolysis of ATP drive non-spontaneous reactions in a cell? atpounc esonamouse,i t smus c l escons ume10uni t sofpot ent i al ener gy( whi c ht hec at 14. Asac pr ev i ous l ygai nedf r om t hef oodi tc ons umed) .Howev er ,t hepounc ei t s el fonl yr equi r ed4uni t sofk i net i c ener gy .Howmanyuni t sofener gywer edi s s i pat edasheat ? A. 2.5 B. 4 C. 6 D. 10 E. 14

15. Whi c hoft hes t at ement si st r ueaboutex er goni cr eact i ons ? A. Exergonic reactions have a positive ΔG.

B.

Exergonic reactions consume energy.

C.

Exergonic reactions are found only in biological systems.

D.

Exergonic reactions are catabolic.

E.

Exergonic reactions measure the strength of an ionic bond.

16. Suppos et hat ,i nagi v enr eac t i on,t heent hal py( H)i nc r easesby10uni t s ,andt hedi s or der( TS) i nc r eas esby12uni t s .Byhowmanyuni t sdi dt heGi bbsf r eeener gyc hange ? A. 2 B.

-2

C.

22

D.

-22

6.5 Enzymes and the Rate of Chemical Reactions (p.127-132) The rate of chemical reactions is increased by protein catalysts called enzymes. LO 6.5 Evaluate the role of enzymes in catalyzing chemical reactions. Terminology: Transition state Activation energy (EA) Substrate Active site Inhibitors Activators Allosteric enzymes Negative feedback Cofactor Self-Assessment Questions: 17. What are three characteristics of enzymes, and how does each permit chemical reactions to occur in cells? 18. Which of the following do enzymes change? ΔG, reaction rate, types of product, activation energy, the laws of thermodynamics? 19. How does protein folding allow for enzyme specificity? nar eact i on,enzy mesc hanget he: 20. I A. activation energy. B.

first law of thermodynamics.

C.

second law of thermodynamics.

D.

types of products.

E.

ΔG. 21. I magi net hatar es ear c hert r i est or educet hesi z eofanenz ymebyr emov i ng al l t heami noac i dsf r om t hepr ot ei nex ceptt hosefl anki ng,andconst i t ut i ng,t he act i v esi t e.Whywoul dn' tt hi swor k ? A. Without the additional amino acids, the protein may not fold properly. B. The removal of the amino acids may affect the ability of the enzyme to bind to substrates. C. The removal of the amino acids will likely affect the shape of the active site.

D. All of these choices are correct....