Lecture 6 Flashcards
(21 cards)
Energy can be stored within _______________
so that it can be used at a later time
chemical bonds
What is the first law of thermodynamics?
Energy is not created nor destroyed,
simply transformed
Why cells cannot use heat to do work?
But cells are too small to be able to use heat
to do work, instead they rely on the energy
found in chemical bonds
What is the second law of thermodynamics?
Disorder
(entropy) in the universe is continuously
increasing
which is more stable order or disorder?
disorder
what is the free energy?
the energy available to
do work.
what is called the reaction where the energy in the bonds of products is lower than energy in bonds of
reactants
exergonic
what is called the reaction where the energy in bonds of products is higher than
those of reactants
endergonic
what does Exergonic reactions will happen
spontaneously
they increase disorder and endergonic will not, as they increase order.
what is activation energy?
the energy required to
destabilize existing bonds in order to start a
chemical reaction
what are the two things that can be done to speed up a reaction?
add energy to it, lower the activation energy
How does catalysts function?
Catalysts function by stabilizing the
intermediate products or transition state of
the reaction, in doing so they speed up the
reaction.
what are enzymes?
Enzymes are macromolecules (generally
proteins, but sometimes RNA) that catalyze
the biological reactions within the cell
what does enzymes (3 things)?
Orienting substrates in the the proper fashion
• Bringing reactants close together
• Stressing particular bonds in the molecules
what does multienzyme complexes allow (3 things)?
The efficient delivery of products to the next
enzyme
– Prevention of unwanted side reactions
– Reactions can be controlled as one unit
how does temperature affects a protein?
slight increases will increase
reaction rates (molecular collisions will
increase so the enzyme is more likely to come
into contact with a substrate), but if the
temperature rises too high, the protein will
denature
how does the pH affects a protein?
The cations and anions produced in acidic or
basic conditions will interact with charged or
polar amino acids in the protein. Eventually
the protein may denature.
inhibitor binds to the active site
competitive inhibition
noncompetitive inhibition, the inhibitor
binds to an allosteric site (not the active
site), changes the shape of the enzyme, thus
inhibiting the binding of the substrate
allosteric inhibitor
what does the km do ?
give us an idea about the affinity
between the enzyme and the substrate
what is the binding affinity between two molecules?
a measure of how strong their non-covalent
interaction is
