REDOX- Chemistry of life
How are oxisdation and Reduction needed in biology
Photosynthesis and Respiration both need REDOX reactions to take place
What is oxididation
When a chemical species loses electrons it is oxidised
What is Reduction
When a chemical species will gain an electrons it has been reduced
What is REDOX
When oxidation and rediction take place at the same time
Atoms that donate electrons are called reducing agemst but are oxidiesed themselves and atoms that accept electrons are called oxidising agenst but themselves are reduced
What are half reactions
REDOX reactions have one oxidising reaction and one reduction reactions
All metals are able to be reducing agents due to become oxidised and donate electrons but have different levels of strengths
How to measure Standard reduction potentials
Can compare different susbatnsces in an electrochemical cells
They have 2 half cells connnected by salt bridge for elecetron flow
Metals act as electrodes and an electrical flow between them
Then measure the potential difference between the 2 electrodes
The oxdising metal becomes + and reducing agents become -
The size of potential difference is proportional to readiness that electrons are domnated by reducing agent
What is the standar Hydrogen electrode
Used to record relative half cell potential of other metals under standard conditions of 1 M H+
Can determine what metals are stronger reducing agents due to more - potential difference
What is the oxidation number
Provide a way to keep track of electron movement during a reaction in where atoms are oxidised and reduced
Increase in oxidation number = Oxidation has occured
Decrease in oxiidation number = Reduction has occcured
How to assign oxidation numbers
Draw out the structure to show electrons shared equally between pair of ataom in covalent bond
Redraw structure as if it was ionic bond to shwo the electrons associated with most electronegative atom
Substract the number of electrons in ionic model from the number of electrons in covalent model to get oxidation number
What is respiration
The breakdown of glucose to release energy by series of REDOX reactions with molecules that are good at carrying electrons
The last step is oxidative phosphorylation so e- are used to pump protons across membrane to make porton gradient that drive ATP synthesis
What is the TCA cycle
In the 2nd half of the cycle Oxoalacetate is regenerated from succinate to prodice FADH2 and NADH that carry electrons fro oxidtaive phosphorylation
How is succinate converted to Fumartae
Due to FAD will gain 2 electrons to become FADH2 so then succinate is oxidised to fumarate and the FAD is reduced
How is Malate formed
This is formed by tbhe hydration of succinate to form malate so is the additon of H2O
What is Malate used for
Used to generate Oxaloacetate by NAD will become NADH so is rediced so the malate is reduced
Need Oxaloacetate to produce citrtae with additon of acetly CoA to start next TCA cycle
What is oxidative phosphorylation
There is the reduction of oxygen to create the electrical membrane potential and proton gradient and turn O2 to H2O
There is a flux of proton that come back into the matrix via ATP syntahse enzyme so ATP is produced
What is the electron transport chain
It is a flow of electrons that are coupled to transport protiens that from the chain
The standard reduction potential tell what way the electrons will flow
Negative Potenial = Give up e- anmd + Potential = Accept e-
How do electrons flow in NADH-Q oxidoredutase complex 1
NADH reduce Flavin
Electrpons pass via series of iron sulfur cluster wherer eahc time REDOX happen an dincrease reduction potential to conenzyme Q
Energy used to pump out 4 protons out of matrix to intermembrane space
QH2 go into complex 3 for furhter redox
How are reducing potential and free energy linked
Reduction potential are a meausre for standard free energu in a REDOX reaction, so determine where equlibrium will lie
DeltaG = -nFDdelta E
n = number of electrons F= Faraday constant
How is ATP synthesized
Proton gradient power ATP synthase enzyme so atp is produced when H+ travel through down the proton gradient back to the matrix
What is the free energy stored in`the proton gradient
Delta G = Delta G of [Proton] + Delta G of electric potential
Delta G proto = RT ln(C outside/ C inside )
Delta G Electrical potential = ZF Delta V