Chapter 17 Flashcards
What are 4 important facts about catabolism
- it is the breakdown of compounds (think cannibalism)
- It is an oxidative process (think CO has cannibals)
- It is the formation of energy (ADP + Pi = ATP)
- It is converging (cannibals converge)
What are 4 important facts about anabolism
- It is the synthesis of compounds (think Ana brings people together)
- It is a reductive process (think Ana reduces tension)
- It requires energy (ATP goes to ADP + Pi)
- It is diverging
Metabolites
intermediates in metabolic pathways
Allosteric inhibitors/activators
deal with the T/R states (think the stereo can be loud - tense - or low - relaxed)
Covalent modification
deals with the A/B states (A= more active, B = less active)
phosphorylation and dephosphorylation
Phosphorylation
done by using a kinase to add a phosphate group
brings a compound to the A (more active) state
ATP to ADP
Dephosphorylation
done by using a phosphatase to remove a phosphate group
brings a compound to the B (less active) state
H20 to Pi
Flux of material through metabolic pathways depend upon two things
- amount of substrate and removal of product
2. activity of enzymes that catalyze the reactions
Near equilibrium reactions
Q is about equal to the Keq
Reactions are readily reversible
Regulated by concentrations of substrates and products
Irreversible reactions
Q is significantly lower than the Keq
Far from equilibrium
Not regulated by concentrations but by catalytic activity through allosteric regulation
When Q is less than Keq that means that there is more (reactant/product) than (reactant/product)
Reactant than product
Non equilibrium equation
Delta G = Delta G knot - RTln(Q)
Q = (Product/Reactant)
Equilibrium equation
Delta G knot = RTln(Keq)
Phosphoester bond
The low energy bond in ATP
(connection of phosphate to Adenosine)
(-O-P-O-CH2-)
Phosphoanhydride bond
The high energy bonds in ATP
(connection between gamma, beta and alpha phosphates)
there are 4 of them (O-P-O-P-O-P-O-CH2))
Phosphoryl transfer
Transferring the gamma phosphate and leaves behind a ADP
Pyrophosphoryl transfer
Transferring the gamma and beta phosphates and leaves behind a AMP
Adenylyl transfer
Transferring the alpha phosphate and the adenosine and leaves behind 2 inorganic phosphates
3 reasons for the high free energy of ATP hydrolysis
- Less charge repulsion in products
- More resonance (more stable)
- Products rapidly ionize
Substrate level phosphorylation
ATP is generated directly by transfer of a phosphoryl group from a “high energy” compound
ADP + Pi (from high energy compound) forms ATP
Oxidative phosphorylation
ATP is generated indirectly using the energy supplied through proton concentration gradients
Kinases
Transfer phosphoryl groups to and from ATP
Phosphate compounds with free energy more negative than -30kJ/mol
Considered “high energy” phosphate compounds
can donate phosphates to ADP to create ATP
Phosphate compounds with free energy less negative than -30kJ/mol
Considered “low energy” phosphate compounds
ATP can donate phosphate to these compounds
Phosphocreatine
Used to regenerate ATP rapidly in the muscle and nerve cells via action of creatine kinase
Example of near equilibrium reaction
Thioesters and ATP have similar ___
free energies of hydrolysis
Nucleoside diphosphate kinase
Takes ATP + NDP and turns it into ADP + NTP Reversible reaction (near equilibrium)
Nucleoside monophosphate kinase
Known as adenylate kinase
Takes 2 ADP and turns it into AMP + ATP
This is important because ADP accumulates when ATP is hydrolyzed
