lesson 7

Question 1

positive delta G reactions require enrgy to proceed

Answer 1

products have more free energy than reactants (products have higher H or lower s) or both
energy must be supplied=not spontaneous (endergonic)

Question 1

gibbs free energy

Answer 1

G= energy available to do worl
G=H-TS
H=enthalpy
T=temp (K)
S=entropy

Question 2

negative delta g tend to occur spontaneously

Answer 2

products have less free energy than reactions (products have lower H or higher S) or both
energy is released=spontaneous (exergonic)

Question 3

activation energy

Answer 3

extra energy required to destabilize existing bonds and initiate a chemical reaction
exorgnic rate depend son activation energy required (large ae= slower reaction)
increase reaction rate: increase heat or use a catalyst to lower ae

Question 4

catalyst

Answer 4

substances that influence chemical bonds in a way that lowers ae of a reaction
cannot violate laws of thermodynamics

Question 4

enzymes are biological catalysts

Answer 4

-many proteins and some RNA molecules acts as enzymes
-enzyme shape stabilizes transient association between substrates
-enzyme not changed or consumed in reaction
different cell types contain different enzymes
-may be soluble or associated with membranes

Question 5

active site

Answer 5

a pocket or cleft for substrate binding
precise fit of substrate

Question 6

factors that influence enzyme function

Answer 6

-concentration of substrate
-concentration of enzyme
-any chemical or physical condition that affects the enzymes structure (Temp, ph, regulator molecules)

Question 7

adenosine triphospahte (ATP)

Answer 7

source of chemical potential energu
high energy bonds between phosphate groups (energy storage)
hydrolysis of these unstable bonds provides energy to drive energonic reactions
hydrolysis produces ADP, P1 and AMP
atp not suitable for long term energy storage (fats and carbs better)