BIO 111 Hawkins Exam 2 Questions and Answers |Complete Solutions Graded
A+|100% Correct
free energy the portion of a system's energy that can preform work when temperature and
pressure are uniform throughout the system (as in a living cell)
enthalpy in biological systems, this is equal to the total energy
T symbolizes the absolute temperature in Kelvins
substrate the reactant an enzyme acts on
enzyme-substrate complex the enzyme binds to its substrate forming an
active site a pocket or groove on the surface of an enzyme where catalysis occurs
stable in a spontaneous reaction, the system tends to move towards a more _____ state
equillibrium a state of maximum stability (free energy of the mixture of reactants and
products deceases as a reaction moves towards this state)
never systems ______ spontaneously move away from equillibrium (and therefore cannot
do work)
toward a process is spontaneous and can preform work onky wheb it is moving toward
equillibrium
exergonic reaction (energy ourward) this reaction proceeds witha net RELEASE of free
energy (dG is negative)
,greater the ______ the decrease in free energy, the ______ the amount of work that can be
done
requires the breaking of bonds ________ energy
endergonic reaction (energy inward) this reaction is one that absorbs free energy from its
surroundings (dG is positive) (nonspontaneous)
anount of work magnitude of dG in an excergonic reaction represents the maximum
__________ the reaction can preform
energy required magnitude of dG in an endergonic reatcion represents the quantity of
_______ to drive the reaction
minimum systems at equillibrium are at a ________ of G and can do no work (cell at
equillibrium is dead)
chemical work the pushing of endedgonic reactions that would not occur spontaneously,
such as the synthesis of polymers from monomers
transport work the pumping of substances across membranes against the direction of
spontaneous movement
mechanical work the contraction of muscle cells, and the movement of chromosomes
during cellular reproduction
chemical, transport, mechanical cells do 3 main kinds of work:
, energy coupling the use of an excergonic process to drive an endergonic one
ATP responsible to mediating most energy coupling in cells, and mostly acts as the
immeadiate source of energy that powers cellular work (made of ribose, adenine, and 3
phosphates)
catalyst a chemical agent that speeds up a reaction without being consumed by the reaction
activation energy the initial investment of energy for starting a reaction-the energy required
to contort the reactant molecules so the bonds can break
transition state when molecules have absorbed enough energy for bonds to break, the
reactants are in an unstable condition
induced fit brings chemical groups of the active site into positions that enhance their ability
to catalze the chemical reaction
ways enzymes lower Ea barrier 1. fixing the substrate orientation 2. covalently bonding to
the substrate 3. straining substrate bonds 4. providing favorable microenvironment
cofactor non-protein helpers to enzymes for catalytic activity (may be bound tightly to the
enzyme permanently, or may bind loosely and reversibly)
coenzyme and ORGANIC cofactor (like vitamins)
competitive inhibitors reduce the productivity of enzymes by blocking substrates from
entering active sites
A+|100% Correct
free energy the portion of a system's energy that can preform work when temperature and
pressure are uniform throughout the system (as in a living cell)
enthalpy in biological systems, this is equal to the total energy
T symbolizes the absolute temperature in Kelvins
substrate the reactant an enzyme acts on
enzyme-substrate complex the enzyme binds to its substrate forming an
active site a pocket or groove on the surface of an enzyme where catalysis occurs
stable in a spontaneous reaction, the system tends to move towards a more _____ state
equillibrium a state of maximum stability (free energy of the mixture of reactants and
products deceases as a reaction moves towards this state)
never systems ______ spontaneously move away from equillibrium (and therefore cannot
do work)
toward a process is spontaneous and can preform work onky wheb it is moving toward
equillibrium
exergonic reaction (energy ourward) this reaction proceeds witha net RELEASE of free
energy (dG is negative)
,greater the ______ the decrease in free energy, the ______ the amount of work that can be
done
requires the breaking of bonds ________ energy
endergonic reaction (energy inward) this reaction is one that absorbs free energy from its
surroundings (dG is positive) (nonspontaneous)
anount of work magnitude of dG in an excergonic reaction represents the maximum
__________ the reaction can preform
energy required magnitude of dG in an endergonic reatcion represents the quantity of
_______ to drive the reaction
minimum systems at equillibrium are at a ________ of G and can do no work (cell at
equillibrium is dead)
chemical work the pushing of endedgonic reactions that would not occur spontaneously,
such as the synthesis of polymers from monomers
transport work the pumping of substances across membranes against the direction of
spontaneous movement
mechanical work the contraction of muscle cells, and the movement of chromosomes
during cellular reproduction
chemical, transport, mechanical cells do 3 main kinds of work:
, energy coupling the use of an excergonic process to drive an endergonic one
ATP responsible to mediating most energy coupling in cells, and mostly acts as the
immeadiate source of energy that powers cellular work (made of ribose, adenine, and 3
phosphates)
catalyst a chemical agent that speeds up a reaction without being consumed by the reaction
activation energy the initial investment of energy for starting a reaction-the energy required
to contort the reactant molecules so the bonds can break
transition state when molecules have absorbed enough energy for bonds to break, the
reactants are in an unstable condition
induced fit brings chemical groups of the active site into positions that enhance their ability
to catalze the chemical reaction
ways enzymes lower Ea barrier 1. fixing the substrate orientation 2. covalently bonding to
the substrate 3. straining substrate bonds 4. providing favorable microenvironment
cofactor non-protein helpers to enzymes for catalytic activity (may be bound tightly to the
enzyme permanently, or may bind loosely and reversibly)
coenzyme and ORGANIC cofactor (like vitamins)
competitive inhibitors reduce the productivity of enzymes by blocking substrates from
entering active sites
