Chapter 7 Flashcards
Energy
Capacity to do work
Name the states of energy
Kinetic energy
Potential energy
Energy in motion
Kinetic energy
Stored energy
Potential energy
Name 5 forms of energy
H.E.L.M R
Heat Electric Light Mechanical Radioactivity
How is heat measured?
In kilocalories
1 calorie =
The amount of heat needed to raise the temperature of water by 1 degree Celsius
1 kilo calorie =
1,000 calories
1st Law of thermodynamics
Energy cannot be created or destroyed
Energy can only be converted from one form to another
Concerns amount of energy in the universe
2nd Law of thermodynamics
Order is more likely than disorder
Concerns the transformation of potential energy into heat or molecular motion
Entropy is always increasing
Entropy
Disorder in the universe
Thermodynamics
Branch of chemistry that deals with energy changes, or “heat changes”
Potential energy stored in chemical bonds can be transferred from one molecule to another by way of ____________
Electrons.
Oxidation
Loss of electrons
Reduction
Gain of electrons
What is the most common electron acceptor?
Oxygen
Reduced form of a molecule has a higher ______________ than the oxidized form
Level of energy
Breaks the chemical bonds that hold atoms together
Energy
Heat energy
Increases atomic motion
Makes it easier for atoms to pull apart
Free energy
Energy available to do work or break and form other chemical bonds
Denoted as the symbol G (Gibbs free energy)
Enthalpy
Energy contained in a molecules chemical bonds
G = H - (TS)
What does each letter represent?
G = Free energy
H = Enthalpy
T= temperature
S= entropy
What creates changes in free energy: G= H-(TS) ?
Chemical reactions
A) Reduces
B) Increases
1) Chemical bonding _________ disorder.
2) Heat ________ disorder.
1) A
2) B
G = H - (TS)
When is G positive?
When products contain more free energy than reactants
Energy is supplied
G = H- (TS)
When is G negative?
When reactants contain more free energy than products
Energy is released
Endergonic reaction
G= H-(TS)
G is positive (products of the reaction contains more free energy than reactants)
Inward energy
Exergonic reaction
G=H-(TS)
G is negative (reactants of the reaction contain more free energy than the products)
Outward energy
The transfer of energy in chemical reactions can be described as either __________ or _____________
Endergonic (inward)
Exergonic (outward)
Most reactions require _______ to get started
Energy
Activation energy
Extra energy needed to get a reaction initiated or started
Destabilizes chemical bonds
Used in endergonic and exergonic reactions
Large amounts of activation energy can slow down reactions
Catalyst
Substance that lowers activation energy
Does not alter proportion of reactant
The chief energy “currency” of cells, powers almost every energy requiring process in cells.
ATP
Describe ATP structure :
Adenine
Ribose (5-carbon sugar)
3 phosphates
Where does ATP store energy?
Bonds between phosphates
Describe Phosphates :
Highly negative
Repel each other (phosphates)
Require a lot of energy to keep phosphates bound to each other
Releases a lot of energy when bond between phosphates is broken
When the bond between phosphates is broken ATP converts to __________, therefore energy has been ___________
(T/F) This reaction is not reversible?
ADP + P(i)
Released
False. Reaction is reservable.
What makes ATP an effective energy donor?
Instability
Is ATP a good long term energy storage molecule?
No. It is unstable (instability)
What fuels the production of ATP from ADP + Pi?
The energy released from an exergonic reaction
ATP hydrolysis
The energy released when ATP is broken down to ADP
Fuels endergonic reactions
Enzymes
Molecules that catalyze reactions in living cells
Most are proteins
Lower activation energy required for reaction not changes or consumed by the reaction
Interact with substrates
What enables an enzyme to stabilize a temporary association between substrates
Unique 3- dimensional shape
Substrate
Molecule that will undergo a reaction
Active site
Region of the enzyme that binds to the substrate
Binding of an enzyme to a substrate causes the enzyme to
Change shape= producing a better induced fit between the molecules
Bringing 2 substrates together in the correct orientation causes an enzyme to
Lower its activation energy required for new bonds to form
T/F
Not all enzymes are proteins.
True
Ribozymes
RNA with enzymatic abilities.
