test 4 lec 20 Flashcards
what does additivity helps
makes it possible to do work by coupling an energy yielding reaction to an energy spending one
if delta G is pos
reaction will go in reverse
what is delta S based on
number of states of system
what represents the state of greatest entropy
the random distribution of molecules at uniform concentration
if entropy increases then…
reactions in which a complex molecule is broken down to a greater number of smaller molecules increase entropy
+ delta S
what does the delta G value of a reaction determines
how much energy is potentially available to do work under defined conditions
many of the cell’s energy transfer reactions involve what
energy carriers
electron donors are
reducing agents, donate electrons
at the end of the series of oxidation-reduction transfers, the electrons are transferred to
a terminal electron acceptor
rate of reaction is determined by
the activation energy
what factors determine delta G
intrinsic properties of a reaction
concentrations of reactants and products
environmental factors
what is different from NADH to ATP
carry two or three times as much energy as ATP
also donates and accepts electrons
what is an allosteric site
found in enzyme with with catalytic site
regulatory site from the substrate binding site
alters conformation of enzyme increasing the rate of reaction
who does catabolism provide energy for
anabolism
what is needed in order to keep energy from releasing all at once and as heat
need to use steps to create energy release, smaller energy change
what measures the heat released or absorbed during a reaction
calorimeter
purpose of standard conditions for delta G
enable scientists to compare intrinsic properties of reactions
what are the three different ways that ATP transfer energy to cell processes
hydrolysis releasing phosphate
hydrolysis releasing pyrophosphate
phosphorylation of an organic molecule
what is entropy
a measure of the disorder or randomness of a system
what is enthalpy
a measure of the heat energy in a system
how does continual growth occur in a cell
a continual gain of energy and continual radiation of heat
+ delta H
reactants absorb heat
what are energy carriers
molecules that gain or release smalls amounts of energy in reversible reactions
if molecular stability increases then…
reactants combine to form products with more stable bonds
- delta H
- delta H
heat is released and provides energy
delta S driven reactions depend on
temp
why do different rxns use different energy carriers
different redox levels
different amounts of energy
regulation and specificity
soma energy carriers also transfer what
electrons
what are the standard conditions for delta G
298 K
1 atm
1 M
to provide energy, a biochemical reaction must go
forward from reactants to products
cells use energy for what
assemble simple, disordered molecules into complex, ordered forms
what is anabolism
reactions that build complex biomolecules from smaller precursors
biosynthesis
cell build order by spending the energy they gain through…
catabolism, lithotrophy, and phototrophy
what are ex of energy carriers
ATP and NADH
electron acceptors are
oxidizing agents, receives electrons
if delta G is neg
process may go forward
how do enzymes lower the activation energy
by bringing the substrates in proximity to one another and by correctly orienting them to react
catalytic site
what is syntrophy
pairing of multiple species to achieve a chemical reaction that, carried out on its own, would be energetically unfavorable
what does Delta H mean
the heat absorbed or released as reactants become products at constant pressure
what are some characteristic of FAD
reduced by two electrons
two protons
donates two electron to an electron acceptor
what is phosphorylation of an organic molecule
atp can transfer phosphate to -OH group of a molecule to activate it
low to high concentration does what to entropy
decreases
does the cell grow by gaining or losing energy
gaining
what is entropy
measure of the disorder or randomness of a system
what does delta S mean
change in entropy or disorder
wha is a concentration gradient good for in a cell
across membrane can be used to store energy for the cell
overall reduction of NAD+ consumes what
two hydrogen atoms to make NADH
a reaction yields energy for the cell if
molecular stability increases
entropy increases
what is catabolism
the breakdown of complex molecules into smaller ones
yield energy
what is energy
the ability to do work
ATP always forms a complex with
Mg2+
as order increases, what happens to entropy
decreases
