Energy Metabolism (2) Flashcards
What does the digestion of nutrients often start with?
Hydrolytic reactions (Breakdown of polymers such as starch, proteins, etc.)
Does hydrolysis usually have positive or negative free energy?
Negative
What is the main reason that hydrolysis usually has negative free energy?
The abundance of water
What concentration does water have in an aqueous solution?
and what are the concentrations of other reaction partners?
55.5 M
Other reaction partners are usually present in mM concentrations
The concentration of water will drive any reaction …
towards hydrolysis
How does free energy change?
With the dislocation from the equilibrium of the concentration of the reactants
What happens if products and substrates are at equilibrium (in terms of energy)
No energy can be gained from the reaction
What happens if concentrations are far from the equilibrium? (energy)
The reaction can proceed and generate energy
The further from equilibrium reaction is held the more energy it can provide
An example of where this equilibrium principle is used in the body?
Used by the body to store ATP
According to the free energy of hydrolysis how much ATP would be hydrolyzed to ADP
Almost all ATP ( 1 ATP for every 100,00 ADP)
In a living cell, however, is the reaction ATP to ADP near equilibrium?
No, it is kept far away from equilibrium (usually about 5-10 times more ATP than ADP)
and therefore can provide and store energy
What is ATP used for
It is a common intermediate required to drive unfavourable reactions
What kind of reactions is ATP used in?
A variety
- Maintaining ion gradients
- Protein synthesis
- RNA turnover
- Movement
- Metabolic Pathways
How is oxidative energy stored in the body?
as NADH or NADPH
How many electrons and proteins can NAD+ accept
Two electrons and a proton to form NADPH
