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In this module we will review Red/Ox reactions and relate them to metabolic process. We will introduce the electron tower, a tool to be used to understand red/ox half reactions and the energy associated with different reactions.

Red/ox reactions in biology

Earth’s atmosphere contains about 20% molecular oxygen, O 2 , a chemically reactive gas that plays an essential role in the metabolism of aerobic organisms and in many environmental processes that shape the world. The term oxidation was originally used to describe chemical reactions involving O 2 , but its meaning has evolved to refer to a broad and important reaction class known as oxidation-reduction (red/ox) reactions . Our current working definition of oxidation is based on the ability of a compound to lose electrons, and removes all references to the involvement of molecular oxygen. A few examples of such reactions will be used to develop a clear picture of this classification of essential biochemical reactions.

The chemical reactions underlying metabolism involve the transfer of electrons from one compound to another by processes catalyzed by enzymes. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a hydrogen atom, in the form of a hydrogen ion or proton, (H + ) and an electron, breaking the molecule into smaller parts. During the loss of an electron(s), or oxidation from one compound, the elctron(s) are then passed to another molecule in a process called reduction , or the gaining of an electron. These two reactions always happen together in an oxidation-reduction reaction (also called a red/ox reaction)—when electrons are passed between two molecules, the donor molecule is oxidized and the recipient molecule is reduced. These reactions are exergonic    . Remember, an exergonic reaction is a chemical reaction where the change in the free energy is negative (there is a net release of free energy), indicating a spontaneous reaction. Oxidation-reduction reactions often happen in a series: A molecule that has just been reduced may be very quickly re-oxidized, passing on an electron to a new acceptor.

Remember the definitions of oxidation and reduction :

oxidation = loss of electrons reduction = gain of electrons

Also remember, that if a compound is oxidized another compound must be reduced. The two process go together. The electrons have to go somewhere, we can not have free floating electrons in our system, they must be associated with a molecule or atom. This is an essential concept.

Red/ox in metabolism

One of the primary sources of cellular energy comes from Oxidation-Reductions reactions, termed red/ox . During the movement of electrons from one molecule to a second, energy is released, and that energy can be used to work (translocate protons) or be stored (ATP synthesis) for future work. This is true as long as the electrons are passed from one compound to a second compound with a higher reduction potential , that is a compound that has a higher affinity for those electrons. The concept of reduction potential is explained below.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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what does post-translational control refer to?
Teresa Reply
Bioremediation includes
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Source:  OpenStax, Ucd bis2a intro to biology v1.2. OpenStax CNX. Sep 22, 2015 Download for free at https://legacy.cnx.org/content/col11890/1.1
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