Metabolism Flashcards
what is energy?
capacity to do work
what is work
change in arrangement of matter
how do living cells do work?
by transorming energy forms
can energy exist in many forms
yes - kinetic, thermal…
define: metabolism
sum total of biochemical reactions occuring in cells
define: anabolism
building up simpler molecules into more complex ones
-requires energy (endergonic/endothermic)
define: catabolism
breaking down complex molecules into simpler ones
-releases energy (exogonic/exothermic)
what is gibbs free energy
energy content
how is energy transferred?
through atp and redox reactions
describe atp
allows energy to be cycled between catabolic and anabolic reactions
atp + h20 ADP + Pi delta G = -30.5kjmol-1
describe phosphorylation
atp hydrolysed to adp and pi
pi attaches to reactant
pi and other reactant swap, enabling joining of reactants
describe oxidatio
reactant loses electrons
adds oxygen and removes hydrogen
releases energy
describe reduction
reactant gains electrons
adds hydrogen and removes oxygen
releases eergy
examples of oxidation?
NAD+ and NADH
FAD and FADH2
families of enzymes? (HOTILL)
hydrolases Oxido-reductases transferases isomerases ligases lyases
effect of enzyme affinity on ror?
substrate’s attraction to enzyme
lower ea reaches same RR eventually but lower than substrate iwth higher ea
describe enzyme inhibitors
- reversible: competitive and non competitive
- irreversible: poisions
how to non competitive inhibitors work in haemoglobin
allosteric activator goes into allosteric site and keeps active site its functioning shape. allosteric inhibitor goes into allosteric site, changes shape of active site, lowering activity
describe effect of competitive inhibitors on ror
reaches same ROR eventually but gets there more slowly
describe effect of non competitive inhibitors on ror
ror tapers off lower
describe how enzymes are regulated
- taking away product or adding substrates to push equilibrium forward
- change the number of enzymes (eg. when we consume more alcohol we form more alcohol dehydrogenase_
- allosteric and competitive regulation
- compartmentalisation of enzymes
define: positive feedback
product of a reaction pathway stimulates an enzyme catalysing a reaction early in the sequence
define: negative feedback
product of a reaction pathway inhibits an enzyme catalysing a reaction early in the sequence
