Chapter 8 Flashcards
Laws of Thermodynamics
apply to all matter and all energy
transformations in the universe
First Law of Thermodynamics
Energy is neither created nor
destroyed
Seconded Law of Thermodynamics
When energy is converted
from one form to another, some of that energy becomes
unavailable to do work.
Entropy
measure of disorder in a system
Enthalpy (H)
total energy
Free Energy (G)
usable energy that can do work
Exergonic Reactions
Release free energy
Endergonic Reactions
Consume free energy
Catabolism
complexity decreases (generates disorder) Complex molecules
Anabolism
complexity (order) increases
Free energy + small molecules
Energy
Ability to do work/change
Enzyme Substrate-Complex (ES)
held together by hydrogen
bonds, electrical attraction, or covalent bonds
Exergonic
release energy (‐ΔG)
Induced fit
enzyme changes
shape when it binds substrate,
altering shape of active site
Kinetic Energy
energy of movement
metabolism
sum total of all chemical reactions occurring in a biological system at a given time
non-competitive inhibitor
bind to enzyme at site other than
the active site
potential energy
stored energy (stored as chemical
bonds, concentration gradient, or charge imbalance)
products
substance present at the end of a reaction
reactant
substance present at the beginning of a reaction
ribozyme
(RNA) molecule that can catalyze chemical reactions
standard free energy
the change in free energy that occurs when 1 mol of a substance in its standard state is formed from the component elements in their standard states. Free energy=change in enthalpy- Temperature in kelvin x change in entropy
substrate
reactants; molecule(s) on which an enzyme exerts
its catalytic action
transition state
eactive mode of the substrate (aka – reactant)
after there has been sufficient input of energy to initiate the
reaction
transition state intermediate
unstable reactants with high free energy
uncompetitive inhibitor
bind to enzyme‐substrate complex,
preventing release of products
competitive inhibitor
compete with natural substrate for
binding sites
activation energy
amount of energy required to start a
reaction
active site
place on an enzyme where substrate binds
allosteric regulation
an effector binds an enzyme at a site
different from the active site, changing the enzyme’s shape
reversible inhibition
inhibitor bonds noncovalently to the
active site, preventing substrate binding
irreversible inhibition
inhibitor covalently bonds to side chains
in active site and permanently inactivates the enzyme
Enzyme inhibitors
molecules that bind to the enzyme and slow
reaction rates
Prosthetic groups
non‐amino acid groups
bound to enzymes
inorganic cofactors
ions permanently
bound to enzyme
coenzymes
small carbon‐containing
molecules; not
permanently bound
