Introduction to metabolism Flashcards
Define: metabolism
all chem re’s occuring in a cell/org in order to sustain life
metabolism is comprised of
catabolism and anabolism (and coupled by intermediates eg. ATP, NAD, NADH, FAD)
define: energy
capacity to do work
define: kinetic energy
energy of motion
define: potential energy
energy of state/position; including energy stored in chemical bonds
define: gibbs free energy
potential energy of a chemical system; amount of energy capable of doing work in a reaction
delta G, delta G0, delta G0’
free energy change
standard free energy change
standard free energy change at neutral ph and 5. M H2O
when K(eq)>1
delta G ‘ = neg, reaction goes forwardq
when K(eq)=1
delta G’ = 0, equilibrium
when K(eq)<1,
delta G’ = pos, reaction goes backwards
describe atp structure
3x phosphate groups + ribose sugar + adenine
why is hydrolysis of phosphodiester bonds very exergonic?
reduces the number of adjacent negative (hence repulsive) charges from 4 to 2/3
ADP and Pi are stabilised by resonace structures
H+ is a product, so the reaction is shifted forward, enhancing effects
how does ATP lower delta G of reactions
substitute reactions into each other.
final delta g is found by adding the first 2 delta g’s
spontaneity of oxidation reactions?
very; but not necessarily quick ROR
spontaneity of hydrolysis reactions?
very
