Bioenergetics Flashcards
What is an oxidizing agent?
a substance that tends to bring about oxidation by being reduced and gaining electrons
What is a reducing agent?
a substance that tends to bring about reduction by being oxidized and losing electrons
The production of NADH and FADH2 involves what type of reactions?
oxidation-reduction
How many ATP will be produced by 1 glucose molecule?
38 ATP
Number of acetyl CoA formed from one molecule of glucose is?
2
Define Thermodynamics
Thermodynamics is a branch of Physics that deals with energy changes.
Define Bioenergetics
The study of the changes in energy during metabolic reactions.
_________ is part of thermodynamics.
bioenergetics
State the laws of thermodynamics
- Energy may change form, or transported from one place to another but it cannot be destroyed or created.
- Any spontaneous chemical or physical change is always accompanied by increase in the disorder of the universe.
In the process of transforming energy, how must living organisms affect the universe?
living organisms must increase the entropy of the universe
In order to maintain organization within themselves, living systems must be able to?
- extract useable energy from the surrounding
2. release useless energy (heat) back to the surrounding
What is Gibbs free energy?
energy that can do work when temperature and pressure are uniform, as in a living cell
What is free-energy change (ΔG)?
a measure of the chemical energy available from a reaction
What is the Gibbs-Helmholtz equation?
ΔG = ΔH - TΔS
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) predicts whether a reaction is favorable?
ΔG
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) approaches zero as reaction proceeds to equilibrium?
ΔG
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) is the energy available to do work?
ΔG
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) is heat released or absorbed during a reaction?
ΔH
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) does not predict whether a reaction is favorable?
ΔH and TΔS
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) is change in entropy (a measure of randomness)?
ΔS
Which part of the Gibbs-Helmholtz equation (ΔG = ΔH - TΔS) is change in enthalpy?
ΔH
What does enthalpy represent?
Represents the heat content of the reacting systems
If heat is released during a reaction, i.e. ΔH is _______, then this is an _________ reaction.
negative; exothermic
If heat is absorbed during a reaction, i.e. ΔH is _______, then this is an _________ reaction.
positive; endothermic
What is entropy?
it is a quantitative expression for the randomness or disorder in the system
If entropy decreases in an organism, it [decreases/increases] in the universe.
increases
In an [endergonic/exergonic] reaction, ΔG has a negative value.
exergonic
In an [endergonic/exergonic] reaction, ΔG has a positive value.
endergonic
An [endergonic/exergonic] reaction proceeds with a net release of free energy.
exergonic
An [endergonic/exergonic] reaction is spontaneous.
exergonic
An [endergonic/exergonic] reaction absorbs free energy from its surroundings.
endergonic
An [endergonic/exergonic] reaction is nonspontaneous.
endergonic
What is free energy?
Free energy is a measure of a system’s instability, its tendency to change to a more stable state
During a spontaneous change, free energy [decreases/increases] and the stability of a system [decreases/increases].
decreases; increases
______ is a state of maximum stability.
equilibrium
A process is spontaneous and can perform work only when it is moving toward?
equilibrium
Define equilibrium
the state in which the chemical activities or concentrations of the reactants and products have no net change over time
What results when the forward chemical process proceeds at the same rate as their reverse reaction?
equilibrium
What is the formula of ΔG0?
∆G⁰ = - RT ln Keq
[ΔG/ΔG0] is the actual free energy change
ΔG
[ΔG/ΔG0] is the standard Free Energy change of a reaction
ΔG0
Describe this: ΔG < 0
spontaneous reaction
Describe this: ΔG > 0
needs energy
Describe this: ΔG = 0
equilibrium
What is the gas constant (R)?
Gas constant = 8.315
1 calorie is equal to how many joules?
4.184 J
