energy and life Flashcards
what is the purpose of metabolism
obtain chemical energy, convert nutrients into cells own molecules, polymerise monomeric molecules into macromolecules, synthesise/degrade biomolecules
what is metabolism
highly coordinated cellular activity composed of multienzyme systems (metabolic pathways)
what is anabolism
using energy to synthesise biomolecules (small to big molecules)
what is catabolism
extracts energy from nutrients
what is a metabolic pathway
instrument to organise metabolic reactions
purpose of metabolic pathways
extract energy, store fuel, synthesis of important building blocks, eliminate waste molecules
how to classify metabolic pathways
according to function
types of non linear metabolic pathways
converging catabolism, diverging anabolism, cyclic pathway
what is cell respiration
process which cell converts food to energy in presence of oxygen
describe 2 types of oxidation of sugar/glucose
- stepwise oxidation of sugar in cells- small Ea overcome by body temp
- direct burning of sugar- large Ea overcome by heat from fire, all free energy released as heat and non is stored
name 3 activated energy carrier molecules
ATP- adenosine triphosphate
NADH- nicotinamide adenine dinucleotide
FADH2- flavin adenine dinucleotide
name 3 stages of cell respiration
glycolysis, citric acid/krebs cycle, electron transport and oxidative phosphorylatino
how does glucose generate ATP
energy/electrons are transferred from glucose to convert NAD+ to NADH and used in electron transport chain to generate ATP
describe what happens in oxidative phosphorylation
NADH and FADH2 generates a H+ gradient, proton gradient is used to regenerate ATP from ADP, oxygen required, oxygen reduced while NADH and FADH2 are oxidised
what are the standard conditions of standard gibbs free energy
25 degrees celcius, pH7 ([H3O]+=10^-7M), [H2O]=55.5M
gibbs free energy equation and units
ΔG=ΔH−TΔS
G= gibbs free energy (Jmol-1)
H= enthalpy (Jmol-1)
S= entropy (Jmol-1k-1)
explain negative ΔG
exergonic, spontaneous, energy released, reaction proceeds
explain positive ΔG
endergonic, reaction does not proceed spontaneously, energy required
equilibrium constant equation
Keq=([C]^c [D]^d)/([A]^a [B]^b )
standard gibbs free energy equation of equilibrium equation
ΔG^0=−RT lnK eq
gibbs free energy equation in an equilibirum
ΔG=ΔG^0+RT ln([C]^c [D]^d)/([A]^a [B]^b )
explain what Keq means when Keq >1.0, =1.0, <1.0
> 1.0= reaction proceeds forward
=1.0= eqm
<1.0= proceeds in reverse
what is chemical bond energy
(pic on onenote)
energy released when bond forms and energy absorbed when bond breaks
why does ATP hydrolysis create a high yield of energy
relief of charge repulsion, resonance stabilisation, greater degree of solvation of products, high ATP concentration
what is reduction
gain of electrons
Fe3+ + e- –> Fe2+
what is oxidation
loss of electrons
Fe2+ –> Fe3+ + e-
what is an oxidising agent
gains electrons, causes oxidation but gets reduced
what is a reducing agent
loses electrons, causes reduction but gets oxidised
how to read electrochemical series
more negative= better reduction strength
more positive= better oxidation strength
all written as Ox+e- –>Red
what is the nernst equation
𝐸^0=−Δ𝐺^0/vF
E^0= standard potential
v= number of electrons
F= faraday constant
what does a positive E^0 mean
negative Δ𝐺
how to calculate reaction potential of oxidation of something
find half equations, reduction potential subtract oxidation potential
importance of alcohol dehydrogenase
present at high levels in liver and stomach, involved in metabolism of alcohol
what is the toxic product of alcohol dehydrogenase
acetaldehyde
importance of acetaldehyde dehydrogenase
metabolises acetaldehyde
result of acetaldehyde dehydrogenase mutations
makes enzyme less effective, less likely to become alcoholic, higher risk of liver damage
