Energy, ATP and Enzymes Flashcards
What are the two subdivisions of metabolism?
- Anabolism
- Catabolism
What is an anabolic reaction?
Provide 2 examples
Anabolic reactions are energy storing (require energy) reactions that link simple molecules together to make complex ones.
ex: DNA replication, protein synthesis, making of starch…
What is a catabolic reaction?
Provide an example
Catabolic reactions release energy; they break down complex molecules into simpler ones.
Ex: Digestion of food molecules for energy generation
Are condensation and hydrolysis reactions catabolic or anabolic?
- Condensation reactions are anabolic
- Hydrolysis reactions are catabolic
What drives energy conversions?
The drive of energy to become evenly distributed.
- Being highly localized to widely dispersed (coffee cup cooling down)
Energy conversions always result in what? (entropy wise)
A state of higher probability- a more disordered state
An increase in entropy
2 ways a cell can release free energy (what forms does energy go to)
- With a chemical reaction creating disorder in the cell
- deltaS: change in entropy in
a closed system - With a chemical reactions releasing heat (generates disorder in turn)
- deltaH: increase in entropy
outside the closed
system
What is equation for change in free energy?
deltaG is favourable when it is what sign?
ΔG=ΔH−TΔS
ΔG is favourable when it is negative because energy is released and spontaneous
4 types of reactions bases on ΔH and TΔS
1) Heat is released (negative ΔH) and disorder increases (positive TΔS). This is always spontaneous (exergonic) because ΔG will always be negative
2) Heat is released (negative ΔH) and disorder is decreased (negative TΔS). ΔG depends on temperature (orderly protein folding only occurs below a certain temperature) When T is large so TΔS is larger than ΔH, then ΔG will be positive.
3) Heat is used (positive ΔH) but disorder increases (positive TΔS). This will positive above a certain temperature
4) Heat is used and disorder decreases. Never spontaneous (endergonic) ΔG=+ΔH−(-TΔS). This applies to most anabolic reactions
Anabolic reactions can only occur by coupling them with _________ to make ΔG ______
Anabolic reactions can only occur by coupling them to exergonic reactions to make overall ΔG negative
How do we know when we are at point of chemical equilibrium?
- When the relative concentrations of A and B are such that forward and reverse reactions take place at the same rate.
- deltaG is 0
How would ATP become ADP
ATP can hydrolyze to create ADP and an inorganic phosphate ion.
This is a very exergonic reaction (releases energy)
ATP + H2O ——-> ADP + P + free energy
Can you predict the rate of a reaction for deltaG?
No!
