Week 1, Lecture 2, ATP and Enzymes

Week 1, Lecture 2, ATP and Enzymes - Answer: BIOLOGY ATP...

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B I O L O G Y 0 2 3 30-Dec-09 Gardiner 1 ATP and Enzymes Currency and Banking Machines Chapter 4 Fig. 4.5 Fig. 4.5 Answer: Answer: • Works by the direct chemical transfer direct chemical transfer of a phosphate group phosphate group . • This is called “phosphorylation phosphorylation . • The exergonic exergonic hydrolysis hydrolysis of ATP ATP is coupled with the endergonic endergonic processes processes by transferring transferring a phosphate group to another molecule. 30-Dec-09 Gardiner 5 • Transfer phospate group from ATP to another molecule, change its free energy so that what was an endergonic ("uphill") reaction becomes an exergonic ("downhill") reaction. • This is called energy coupling . Hydrolysis of Hydrolysis of ATP ATP ATP + H 2 O ADP + P (exergonic) Hydrolysis (add water) PPP Adenosine triphosphate (ATP) PP P + Adenosine Adenosine diphosphate diphosphate (ADP) (ADP) Fig. 4.12
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Dehydration of Dehydration of ATP ADP + P ATP + H 2 O (endergonic) Dehydration synthesis Dehydration synthesis (remove water) (remove water) PPP Adenosine Adenosine triphosphate triphosphate (ATP) (ATP) PP P + Adenosine diphosphate diphosphate (ADP) (ADP) Fig. 4.12 B I O L O G Y 0 2 3 30-Dec-09 Gardiner 8 Chemistry in Cell •Fac to ry -send chemicals through pipes, valves, computer program -complex, hard to miniaturize •Ce l l – Reactants and products in same space – Chemicals interact by random collisions • Total space must be small 30-Dec-09 Gardiner 9 Enzymes • A spontaneous chemical reaction may occur very slowly • Enzymes speed up reactions • A catalyst is a chemical agent that changes the rate of a reaction without being consumed by the reaction – enzymes are catalytic proteins 30-Dec-09 Gardiner 10 Enzymes • In every chemical reaction between molecules bonds must be broken [requires energy] (E) and bonds must be made (releases E) • The initial energy required to break bonds is the activation energy (E A ) • Bonds break only when molecules have absorbed enough energy to become unstable Chemical reactions between molecules involve both bond breaking and bond forming.
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This note was uploaded on 04/18/2010 for the course BIOLOGY 1223 taught by Professor Gardiner/lajoie during the Fall '09 term at UWO.

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Week 1, Lecture 2, ATP and Enzymes - Answer: BIOLOGY ATP...

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