Energy Flashcards
how is energy created/use in the body
metabolism
what is metabolism carried out by
enzymes
what is anabolism
metabolic process that builds complicated molecules from simple ones
what is catabolism
metabolic process of breaking down complex molecules into simpler compounds
which molecules are richer in energy
complex molecules due to multiple bonds
what is thermodynamics
describes energy and its transformation by describing things as a system and its surroundings
biological systems are what kinds of system
open, it exchanges matter and energy with surroundings
what is the first law of thermodynamics
energy cannot be created or destroyed, only transferred and transformed
what is the second law of thermodynamcis
energy and matter move from order to disorder over time
the (entropy in) universe is constantly increasing
what is entropy
the amount/level of disorder
what is low entropy in terms of potential energy
low entropy means it is organized with high potential energy
what is high entropy in terms of potential energy
high entropy means it is disorganized with low potential energy
how can biological systems be ordered but still follow the second law of thermodynamics
cells borrow entropy from somewhere else and decrease entropy locally, but entropy in surrounding increases due to energy and disordered molecules being released into environment
what is Gibbs free energy
the amount of energy of a system available to do work
what is the free energy equation and symbol meaning
G= H-TS
H= enthalpy (total heat energy)
T= temperature
S=entropy
what is an exergonic reaction
negative G (Gibbs free energy), the system loses free energy (can mean increased entropy than what we started with)
what is an endergonic reaction
positive G (Gibbs free energy), system gains free energy (can mean increased enthalpy)
what is a spontaneous reaction
a chemical reaction that will go on its own without any outside influence, often exothermic
what is an exergonic reaction
an energy releasing chemical reaction yielding products that contain less potential energy that the reactants
what is an endergonic reactions
energy requiring chemical reaction yielding products rich in potential energy
what is an energy coupling reaction
the use of energy released from an exergonic reaction used to drive essential endergonic reactions, requires an enzyme
what is the energy of activation
the amount of energy that reactants must absorb before a chemical reaction will start
an energy barrier preventing molecules form breaking down spontaneously
effect of enzyme of energy of activation barrier
can lower the amount of energy required
what is an endothermic reactions
transformations that result in a system taking up heat form its surroundings
what is an exothermic reaction
transformations that release heat
difference between exergonic and exothermic
EXOTHERMIC DOES NOT MEAN EXERGONIC
exergonic- Gibbs free energy being negative
exothermic- change in enthalpy, heat released
what is ATP
the energy currency/shuttle of the living cell
structure of ATP
nucleotide consisting of:
Adenine- nitrogen containing organic base
Ribose- five carbon sugar
three phosphate atoms surrounded by oxygen atoms
function of ATP (4)
- hydrolysis of ATP (exergonic reaction) favors the formation of products in living cells
- donates energy through the transfer of the phosphate group
- nearly all cellular work depends on ATP energizing other molecules using phosphorylation
- reaction can also be coupled to endergonic reactions in cells
two ways to create ATP
substrate level phosphorylation, chemiosmosis
substrate level phosphorylation of ATP
formed when phosphate group is transferred to ADP from a phosphorylated intermediate
what is chemiosmosis
process by which phosphorylation of ADP to form ATP is coupled to transfer of electrons down an electron transport chain
what is oxidative phosphorylation
ATP synthesis driven by electron transfer of oxygen
what is photophosphorylation
ATP synthesis driven by light
where is energy stored in cells
chemical bonds of lipids, starch, and glycogen and energy for immediate use is stored in ATP
what are enzymes
a protein that serves as a biological catalyst
what enzymes do to the equilibrium
allows it to be approached faster
true or false: enzymes change after they act as a catalyst
false, they remain unchanged
what is the active site of an enzyme
region on the surface of an enzyme where the substrate binds, where catalysis occurs
how enzymes cause catalysis (3)
- bring reacting molecules together
- expose reactant molecules to altered change environments that promote catalysis
- change the shape of substrate molecules
how do temp and pH affect enzymes
enzymes have an optimal temp. and pH where they act at peak efficiency
(pH usually near cellular contents, pH 7)
what is an enzyme cofactor
nonprotein group that binds to an enzyme, is necessary for catalysis to occur
what are cofactors
often metallic ions
what are coenzymes
organic molecules
what do reactions depend on
concentration
what happens when substrate is low
reaction rate slows and the enzyme and substrates collide infrequantly
what happens when substrate is high
enzymes become saturated with reactants, rate of reactions increase and then level off
what is enzyme inhibition
a non-substrate molecules that can bind to an enzyme and decrease its activity
what is competitive inhibition
the inhibitor competes with the normal substrate for the active site
what is non-competitive inhibition
when the inhibitor does not compete with the normal substrate for the active site but combines with sites elsewhere in the enzyme
what is feedback inhibition
a type of metabolic regulation where the product of a reaction inhibits tis own synthesis
what are redox reactions
ways for cells to transfer energy through the transfer of electrons, usually with a hydrogen atoms (electron and proton instead of just an electron)
what is oxidation
the process in which a substrate loses electrons, substrate becomes oxidized and gives up energy
what is reducation
process in which a substrate gains an electron, becomes reduces as it receives energy
why is it called a redox reaction
because oxidation and reduction often happen simultaneously
what are acceptor molecules
the molecules that accepts the transferred electron and energy from an organic compound
what are biology carriers
electron carrier
how do bioenergy carriers exist in the body
in reduced states meaning it has more free energy, or an oxidized state meaning it has less energy so it can take or lose electrons
types of bioenergy carriers
NAD+ and NADH
FAD and FAD2
cytochromes
ubiquinone
