Basic Principles Flashcards
Are catabolic pathways oxidative or reductive?
Oxidative (electrons transferred to NAD+ and NADP+)
Lose Electron Oxidation, Gain Electron Reduction, LEO GER
In catabolic pathways, what is energy temporarily captured as?
ATP
What is the second stage of catabolism?
Conversion of monomers to Acetyl CoA in the mitochondria
What happens to Acetyl CoA in the third stage of catabolism?
oxidation to CO2 and H2O, with the storage of energy through oxidative phosphorylation
Are anabolic reaction oxidative or reductive?
Reductive (hydride ions gained from NADPH)
What two molecules are made for long term energy storage?
Glycogen and triglycerol
Which molecule is “devoted” to catabolism? Anabolism?
NAD+/NADH.
NADPH
Catabolism, Oxidative, Exergonic.
Anabolism, Reductive, Endergonic.
COEx
AREn
How is futile cycling prevented?
Paired anabolic/catabolic pathways have at least one of the steps catalyzed by a different enzyme
How are enzymes in metabolic pathways often organized/
Into functional complexes
T/F Paired pathways often occur in different cellular compartments
True
Which metabolic pathways happen in the cytoplasm?
Gluconeogeneis, glycolysis, FA synthesis
Which metabolic pathways happen in the mitochondria?
Citric Acid Cycle, Oxidative phosphorylation, FA degradation(Beta oxidation)
Where does protein synthesis occur? DNA replication?
Ribosomes.
Nucleus
What is G?
Amount of energy capable of doing work during a reaction at constant T and P
-G is indicative of what kind of reaction? +G
Exergonic.
Endergonic
Which reactions are spontaneous in the forward direction? Reverse direction?
Exergonic.
Endergonic
What are the conditions of the Gibbs standard free energy?
[R] and [P] = 1 M T = 25 degrees celsius P = 1 atm pH = 7 [H2O] = 55.5 M (don't worry about water, just for GK)
What is the actual free energy change of G dependent on?
Temperature and Concentration
What do free energy changes predict?
Direction of chemical reactions.
Equilibrium positions
Amount of work that can be performed
BUT, no info about reaction rate and is independent of the path of the reaction
What are the two practical principles of bioenergetics?
- Even a reaction for which the change in standard gibbs free energy is positive can go in the forward direction, if the the change in G is negative.
- The change in standard gibbs free energy of sequential chemical reactions are additive.
How can a situation for the first practical principle (+G can go forward) of bioenergetics arise?
A situation that can arise by prompt removal of the product
How is the second practical principle possible?
An endergonic reaction can be driven forward by coupling it to a highly exergonic reaction through a common intermediate
ATP hydrolysis is facilitated by what three ways?
- Charge separation
- Inorganic phosphate product stabilized by resonance
- Direct product of hydrolysis ADP2- is ionized
How does ATP provide energy?
By group transfers (not by hydrolysis)
What are the two modes of ATP production?
- Direct transfer of a phosphate group to ADP to form ATP
2. Oxidative phosphorylation
Where can substrate level phosphorylation occur?
Cytoplasm or Mitochondria.
Where does oxidative phosphorylation occur?
In the inner mitochondrial membrane
What are some high energy compounds other than ATP?
Phosphoenolpyruvate, 1,3-Bisphosphoglycerate, Acetyl phosphate, phosphocreatine
What are the three levels of metabolic pathway regulation?
Allosteric regulation
Hormonal regulation
Enzyme concentration
What are the three strategies used to regulate competing (catabolism vs anabolism) pathways?
- Using different enzymes to prevent from reactions going backwards
- Organizing enzymes into functional complexes
- Separating paired pathways into different cellular compartments
