chemical reactions Flashcards
What are the 2 forms of energy?
Kinetic energy and potential energy
Kinetic energy meaning
energy of movement
Potential energy meaning
energy due to location or structure
Chemical potential energy
energy stored in atoms and between bonds
thermodynamics
energy being converted to different forms
What are the 2 laws of thermodynamics?
1) energy cannot be created or destroyed; energy can only change from one form to another
2) Any energy transfer or
transformation from one form to
another increases the degree of
disorder of system entropy
(goes from highly ordered to more disordered)
Entropy
measurement of randomness of molecules in a system (unusable energy)
H=
Enthalpy, total energy
G=
free energy (amount of energy that is available)
S=
unusable energy
T=
Temp in Kelvin
Enthalpy (H)
Total energy of a system
Free energy (G)
Amount of energy that is available and can be used to promote change
or do work
Exergonic reaction
- Spontaneous (does NOT mean fast)
Negative free energy (∆G <0) - Energy is released during product formation
- Favors conversion of reactants to products
Endergonic reaction
Positive free energy (∆G > 0)
* Energy is required for product formation
* Not spontaneous
* Favors formation of reactants
Enzymes
- Catalyst
- Agent that speeds up chemical reaction rate
- Enzymes are most common catalysts
- Enzymes are proteins
-help reach transition state (state between reactants and products)
-they lower activation energy
Enzymes work by…
substrates (reactants) bind to specific site on enzyme, which form enzyme-substrate complex which helps get it to transition state
Activation energy is…
the initial
input of energy required to start
any reaction
Steps in an enzyme-catalyzed
reaction
Substrates bind to enzymes (hexokinase) and then conformation change causes induced change which strains the chemical bonds with substrates and brings them closer together, substrates are converted to products, products are released, and enzyme could be reused
Hexokinase is…
an enzyme whose substrates are glucose and ATP
How do enzymes lower activation energy?
-provide platform for substrates (give place for substrates to bind)
-stretch substrate towards transitional form (induced fit phenomenon)
-provided optimal conditions
-may participate directly in the chemical reaction
↑substrate = what velocity
↑ velocity of product
formation
Plateau
Vmax: chemical reactions
maximal velocity
KM
substrate concentration
at which the velocity is half
its maximal value
Activator
help/activate the function of enzyme
Inhibitor: function and types
makes it so enzyme is not functioning
-2 types: irreversible and reversible
Irreversible inhibition
(not reversible), once binded via covalent bond cannot be reused
Reversible inhibition meaning and types
(enzyme can be reused)
2 types:
Competitive inhibition and noncompetitive inhibition
Competitive inhibition
competes with substrate on who binds first to active site, no change in Vmax
Noncompetitive inhibition
binds to allosteric site, when binds it changes the function of enzyme, affects/change in Vmax
