Bioenergetics Flashcards
Enenrgy
capacity of cause specific physical or chemical changes
Chemoheterotroph
human
carbon from organic compounds
Bioenergetic
subset of thermodynamics
how the biological world gain and use energy
1 molecule of glucose can couple with – of ATP molecules
30
chemotrophs
energy from oxidizing mebolic fuel
how many oxidizing state for carbon
5
most oxidizing state of carbon
CO2
1st law of thermodynamics
total energy universe remain the same
2nd law
universe always tend to greater randomness
measure of randomness
Entropy
Delta entropy universe is
positive for every spontaneous reaction
Enthalpy
heat content of a system
Gibbs free energy
dG=dH-TdS
Spontaneous reaction
dG negative
Exergonic
release free energy
nonspontaneous reaction
dG positive
Endergonic
Use free energy
system at equilibrium
dG zero
no net flow
enthalpy and entropy changes are exactly balanced
dG =
dG(0) + 2.303 RTK(eq)
Equilibrium constant
Reaction product conc. to reactant conc.
one way in biological pathway, making a reaction more favourable
constantly using product
Homeostasis
Maintain a dynamic steady state far from equilibrium
Speed of reaction and dG has – relation
no
enzyme kinetic is based on
Activation energy
all cellular processes are catalized by
enzyme or riboenzyme
enzyme/riboenzyme properties
1- required in small amount
2- physiological temperature and pH
3- reusable
4- highly specific to their substrate
5- generate a specific product
6- they change the rate not dG
Metastable rate
thermodynamically unstable but does not have enough energy to exceed activation energy barrier
E(A)
minimum amount of energy required for reactant
Transition state
precise point when equal chance of going to product or substrate
How do enzymes reduce activation energy
1- maintaining precise substrate orientation
2- changiing substrate reactivity
3- exerting physical stress
active site
region enzyme that bind substrate and cofactor
-complimentary pocket accommodate substrate with high affinity
amino acids comprise active site
C/S/D/E/H/K–SHDECK
water and enzyme active siute
water is generaslly excluded from active site if no treactant
metal and vitamins
use as enzyme and cofactor
rest of enzyme rather than active site
1- supopport structure
2- regulatory use
3- site of interaction with other proteins
4- substrate channel
eznymes are characterized by
sensivity to temperature and Ph
before optimal temp, enzyme activity increase when temperature
increases
after optimal temp, increase in temperature will
cause denaturation
pH dependence is due to
charged amino acids at active site
ph change can disrupt ionic and HB bonds
rxn rate is influenced by
concentration of reactant/product/inhibitors
1pr 4domain VS 4pr 1domain
1pr 4domain
one enzyme can regulate many reactions thisw\ way
cells can regulate protein activity by
localization
turn them on/off
amount of enzyme can be regulated by
syntheis/degradation
drug and poisions normally
inhibit specific enzyme
competitive inhibition
inhibitor and substrate both bind to active site
noncompetetive inhibition
inhibitor bind difeerent than active sit, distort enzyme and inhibit substrate binding to active esite
allosteric regulation
bindign an effector molecule at a site rather than enzyme active site
-common in multi subunit pr
–can be inhibitor or activator
enzyme can be inactive/active until
activate/inactivate by covalent modification
