chapter 8 Flashcards
catabolic process
energy yielded
anabolic process
energy used for cellular work
what is required to synthesize ATP
ADP and phosphate
what is ATP used for
most cellular work that requires energy
what is chemical potential energy stored in
ATP
what do enzymes do?
speed up a metabolic reaction by lowering the energy barrier
how are enzymes and catalysts similar
an enzyme acts as a catalyst, as it speeds up a reaction without being consumed within it
How can the activation energy be found on an energy graph
From the height of the reactants to the top of the highest point curve
What do enzymes not change on an energy graph?
delta G
changing an endogonic to an endergonic reaction
what indicates spontaneity
- delta G
why is it inappropriate to speed up these reactions by applying heat
heat denatures the protein and kills cells and speeds up reactions
substrate
reactants that enzymes react on
why are enzymes able to recognize molecular differences
enzymes have specific shapes that dictate their unique functions
active site
where an enzyme binds to its substrate
what do R-groups of amino acids interact with on substrates
chemical groups on the active active site of the substrate
induced fit
enzyme changing shapes slightly to the active site fits more snug on the substrate
induced fit increases what ability of an enzyme
catalytic
how efficient an enzyme is depends on :
temp
pH
specific chemicals
what is the optimal pH for each enzyme
most in between 6-8 pH
what is the optimal temperature for each enzyme
human enzyme– 35-40 C
thermophilic enzyme – 70-80 C
why do reaction rates drop quickly at temps greater than the optimal temperaure
higher temps will disrupt the hydrogen, ionic, and hydrophobic interactions that stabilize the active state
how can you determine which direction a reaction is going
positive or negative delta G
how does the active site environment impact a reaction
favorable micro-environment (can be more acidic than a neutral cell)
cofactors
some enzymes require a non-protein molecules to aid catalytic activity (binds either loosely or tightly)
what are two types of cofactors
organic molecules
inorganic molecules
what are examples of inorganic ions
magnesium
zinc
iron
copper
what are examples of organic molecules
(aka co-enzyme)
most vitamins
NAD+
irreversible inhibitions
when inhibitors bind covalently to the enzyme and block activity
reversible inhibition
when inhibitors bind to enzyme via weak interaction and block activity
what are the two types of reversible inhibition
competitive inhibitors
noncompetitive inhibitors
competitive inhibitors
block substrates from binding to the active site
noncompetitive inhibitors
impede enzyme activity by binding to another part of the enzyme. changes shape so active site is less catalytic
inhibition prevents what from happening
prevents the cell from wasting chemical resources by making more isoleucine than necessary. turns pathway off until isoleucine is needed
what bonds to the allosteric site in inhibition
isoleucine
what is the end product of inhibition
isoleucine
metabolism
totality of an organism’s chemical reactions
each step of a metabolic pathway is controlled by ____ to convert a specific molecule into a product
enzyme
what are the 2 types of metabolic pathways
catabolic
anabolic
catabolic pathway
breaks down sugars into simpler ones, releasing energy
anabolic pathway
builds up complex sugars that require energy
hydrolysis is an example of what type of metabolic pathway?
catabolic
proteins to AA is an example of what type of metabolic pathway?
catabolic
AA to proteins is an example of what type of metabolic pathway?
anabolic
dehydration reaction is an example of what type of metabolic pathway?
anabolic
where do anabolic pathways get their energy from
catabolic pathways
bioenergetics
the study of how organisms transform energy
define energy
capacity to cause change
kinetic energy
the energy associated with the relative motion of objects. Moving matter can perform work
heat is an example of what type of energy
kinetic energy because it is the random motion of atoms
potential energy
energy that is the capacity of the matter to change as a consequence of its location or arrangement
chemical energy is what time of energy
potential energy because it has the possibility to release in a chemical reaction
thermodynamics
the study of energy transformation
what is the 1st law of thermodynamics
energy can be transformed but can not be created or destroyed
what is the second law of thermodynamics
every energy transformation increases the disorder (entropy) of the universe
free energy change
a living system’s free energy is the energy that can do work under cellular conditions (what we use to power our cells)
what does each symbol represent
dG = dH -TdS
dG - free energy change
dH - change in enthalpy (total energy)
T - temp (K)
dS - change in entropy (measure of unavailable energy)
what type of processes have a negative delta G
spontaneous processes
what is the measure of a system’s instability
free energy
What is more stable? high or low free energy
less free energy
what has greater work capacity
higher free energy
do exergonic reactions release or require energy
release
On a graph, if the products end higher than the reactants, is it displaying a exergonic or endergonic reaction
endergonic
is ATP spontaneous
yes
do endergonic reactions release or require energy
require
is ATP hydrolysis endergonic or exergonic
exergonic
when can’t a system do work?
once the reaction reached equilibrium
if a system was completely isolated what would occur
metabolic reactions would stop and cells would die
why do metabolic reactions never reach equilibrium
the reactants and products are always moving in and out of cells
what occurs to glucose in cellular respiration
glucose is broken down in a series exergonic reactions that power the work of a cell
what occurs with the product of cellular respiration when it is complete
they are used as the reactants for the next reaction
what powers cellular work by changing exergonic reactions into endergonic ones
ATP
ATP is used as energy for what types of work
mechanical work
transport work
chemical work
active transport is an example of what type of work
transport
muscle contraction is an example of what type of work
mechanical
synthesis of AA to proteins is an example of what type of work
chemical
what type of reaction uses water to break down a molecule
hydrolysis
why do phosphate groups release so much energy
the negative oxygen on the phosphate groups make them very unstable
what is the product of hydrolysis
breaks the molecule apart, creating ENERGY
what occurs when hydrolyzed ATP is used to transfer a phosphate group to another molecule
produces a phosphorylated molecule that is more reactive and less stable
what is the direct effect of transport work
hydrolysis of ATP phosphorlates the membrane protein, changing its shape to bind with another molecule
whats the indirect effect of mechanical work
ATP binds to motor protein, changing its shape to interact with the cytoskeleton
