Oxygen: Part 1

So it has been an extremely long time since I’ve posted a blog post so I figured today I would end the drought. This is going to be extremely simplified but I hope I explain it enough to where the average joe can take something from this.

I am just about to graduate with my BSc so my posts will revolve around interesting topics in biology/medical sciences from here on out.


So everyone knows we need oxygen to live. Oxygen is a clear colourless gas (O2) that makes up ~ 21% of our atmosphere. Humans are extremely sensitive to anoxia (complete absence of oxygen) and your brain tissue will die under anoxic conditions in about two minutes.

It is common knowledge if you don’t breathe air (and consume oxygen) for a short period of time, you will die. Now I wanted to talk about something more interesting (and less obvious) as to why and how oxygen is also killing us, but as I wrote this I realized that you need to know how we’re actually using it to live in the first place (so in essence, this blog will be a two-part’er).

Oxygen, given the nature of its chemical structure (the number of electrons it has, where it rests in the periodic table, and a bunch of other things) is extremely electronegative. By being electronegative, this means it likes to accept electrons (which are tiny negatively charged particles which surround the nucleus of atoms, which are involved in atomic bonding).  This idea is important to what I am about to say because it is the reason (in a very general sense) why oxygen is implicated in playing a role in our demise and in keeping us alive.

A quick overview of human/cell physiology here: we breathe in air into our lungs, which contains 21% oxygen content. As the oxygen diffuses to the alveoli in our lungs and is exchanged from the lung into the capillaries (the blood vessels) lining the lungs, the concentration that is ‘absorbed’ decreases by a lot. Ultimately, the organelle (a tiny structures you learned about in high school biology that are located within cells) that uses the oxygen is called the mitochondria. How it uses the oxygen relates back to its electronegativity, or its affinity/desire to take on more electrons (those tiny negatively charged particles that surround atoms).

So, we need oxygen because oxygen is used as a ‘collector’ of electrons, or an electron ‘sink’ in the process of energy production. Basically, these little mitochondria that are found in 99% of the cells in our body (there are some cells that don’t have mitochondria) take this oxygen, and use it to pull electrons through their membrane to create a chemiosmotic gradient. Basically, they’re little machines that create a membrane potential (a charge differential) and our bodies use this POTENTIAL (similar to water falling off Niagara Falls through a turbine to create hydroelectric energy) to create energy for every cell in our body (in the form of ATP). In essence, instead of gravity providing the potential energy to create electricity (as the water falls off the cliff, gravity is ‘pulling’ it) oxygen is sitting at the bottom of this hypothetical cliff and pulling electrons down towards it.

This process of electrons being transported through the mitochondrial membrane to create a gradient of potential which can be used to fuel energy creation is very simply how we use oxygen to power our bodies.

Stay tuned for part 2…


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