101 Bioenergetcis Flashcards
What is entropy?
a measure of disorder, it is energy that cannot be reused and it is the dispersal/diffusion of energy
-the ACTUAL meaning is that energy tends to be dispersed, i.e., any spontaneous process will result in an increase in entropy of the whole universe
Metabolic pathways that are energy producing are called? (
catabolic pathways or catabolism. this degrades molecules to produce energy
Pathways that use energy to build complex structures are called?
Anabolic pathways or anabolism. They use energy to build
What is a metabolic pathway?
a series of reactions that can be either catabolic or anabolic in function
In a living system, what is the main source of energy used to reverse the trend of entropy?
the sun/sunlight
For living systems, that have no access to sunlight, what is the main source of energy used to reverse entropy?
thermal energy
What does thermodynamics describe?
describes the behavior of matter as well as the transformation between different forms of energy ( The flow of matter and energy through systems)
What is a system?
a definite region of space w/in a real or imaginary boundary e..g., cell, an organelle, the contents of a breaker
what is meant by surroundings?
everything else outside the system
What is meant by universe
the system + surroundings
are biological systems open, closed, or isolated?
can be all three but biological systems that are not open would be thermodynamically dead
How does energy and matter move in an isolated system?
there is no movement of energy or matter w/its surroundings
How does energy and matter move in a closed system?
there is no exchange of matter but there is exchange of energy with system surrounds
How does energy and matter move in an open system?
can exchange both matter and energy w/surroundings
What is deltaH?
the change in enthalpy, which measures the amount of heat. It also measures the difference in number of bonds and strength of those bonds between the substrate and products
What is the basic equation n bioenergetics of deltaG?
DeltaG=DeltaH-T(DeltaS)
What is deltaG?
the MAX AMOUNT of useful work that can be produced from or is required by a process
What is meant by absolute temperature (T)?
the absolute temperature, which measures the intensity of heat
What is meant by deltaS?
change in entropy, which measures change in chaos/disorder/randomness. This is the form of heat-energy that cannot be reused in chemical rxns
When talking about free energy, what is meant by free?
the term free means available in the form of useful work
What is a spontaneous process?
Processes that are spontaneous do not require energy, instead they release energy. Those process that are not spontaneous, require energy and there must be a source of energy to drive the reaction.
-any spontaneous process will result in an increase in entropy of the whole universe
TRUE OR FALSE: enzymes alter the rate at which a reaction proceeds and the overall energetic parameters of the reaction?
FALSE: enzymes do not alter energetic parameters. Enzymes do not affect thermodynamics
FILL IN THE BLANKS: Enzymes in a reaction affect ______ but not the overall ________
enzymes alter the rate at which a reaction proceeds but not the equilibrium of the reaction
What assumption do we have to make about biological systems/reactions when thinking of free energy change (DeltaG)?
that temp and pressure are constant
What is required for processes that are not spontaneous to proceed (drive the reaction forward)?
energy source is required
What is enthalpy?
the change in the amount of heat. enthalpy is an extensive factor and depends upon how much is burning
What is the units of absolute temperature?
absolute temperature 0 Kelvin or -273 degrees Celsius.
In gibbs free energy, which energy can be used? which cannot be used?
entropy - form of energy that cannot be used (Delta s)
enthalpy - form of energy that CAN be used (HEAT) (delta H)
What is extensive vs intensive?
extensive factors depend upon how much product is present. intensive does not.
in delta G equation, what is extensive and what is intensive?
Ethalpy, delta H is extensive
Entropy, delta S is extensive
Free energy, deltaG is extensive
Absolute temperature, intensive factor b/c it does not depend upon how much is present.
What is meant by a strong bond vs a bond that is not as strong?
it means it takes “a lot” of energy to break that bond. e.g., if bond A has more energy than bond B than bond A is more stable (harder to break) than bond B
When is deltaH more negative?
DeltaH is more negative when the products (compared to substrates) have more bonds, and stronger bonds (e.g., C-triple bond-C > C=C > C-C)
- products < substrates
- when energy is released or the energy level is lower, that means there is a negative value.
When is delta H more positive?
when the products compared to substrates have less bonds, weaker bonds
Products < substrates
When is delta S more negative?
-when there are more substrate molecules than products
Substrate > product
-when entropy is more negative, the reaction tends to flow downhill. in other words SPONTANEOUS
When is delta S more positive?
deltaS is more positive when there are more product molecules than substrate molecules.
product > substrates
Why do some reactions require energy?
some reactions are not spontaneous, meaning they roll uphill, not downhill (downhill = spontaneous)
-in order for the reaction to proceed, work is required to get that reaction to go uphill. The measure of how much work is required is deltaG
What is work?
the amount of energy required when moving a mass
The number of energy in bonds is dependent on what factors? how is this related to enthalpy?
The number of bonds after and the strength of the carbon-carbon bonds.
(the more bonds, the more energy in there)
In terms of enthalpy, when is a reaction spontaneous?
When enthalpy is negative, the reaction tends to flow downhill, aka SPONTANEOUS. The products have more bonds and are stronger
In other words, when a reaction flows downhill, you end up with substrates that have weaker bonds
When is entropy more positive?
When going from substrate to product, entropy is more positive, that is things become more chaotic, more disordered, when there are more product molecules than substrate molecules.
Consider the reaction S → P+Q, will the entropy (deltaS) be negative or positive?
Positive b/c there are more product molecules, hence more disorder, hence more chaos (more thermal motion in two molecules vs one molecule)
Consider the reaction X+Y → Z, will the entropy (deltaS) be negative or positive?
The entropy will be negative, because we went from a chaotic substrate to a less chaotic (less product) product.
