My Wellness Drawer

Archive for the ‘How the body works’ Category

We breathe to capture oxygen, which helps us convert food into energy in our cells, and to get rid of carbon dioxide – the waste gas which is formed as this happens. Our lungs pump these gases in and out of our bodies, and help us dissolve them in and out of our blood.

Okay, let’s go back a bit. If you think about it, cells are like little units of life. The smallest living things, bacteria, are just individual cells swimming about eating stuff. They absorb sugars or other nutrients from the air or liquid around them, and turn this “food” into energy – which they can use to grow, multiply, and squidge around looking for more food.

Got that.

Okay. Now some of these bacteria eventually evolved into bigger creatures like fish, frogs, lizards, monkeys and human beings. Those particular types of bacteria are called aerobic bacteria, which means…

…that they wore tracksuits and did lots of exercise?

Err…no. It means they have to “breathe” (or take in) oxygen in order to turn their food into energy.

Oh yeah, of course. I knew that. I mean, nobody makes tracksuits that small, for starters.

Err…right. Anyway, these bacteria and the animal cells they evolved into all need to take in oxygen for that same reason – to fuel their food-processors and produce energy.

But why do they need oxygen to do that? Couldn’t they do it without oxygen?

Well, they can for a while, at least. But the main power source for aerobic bacteria and cells comes from a chain reaction which uses oxygen – so they can’t survive without it for long. Oxygen and nutrients go into this reaction, then energy and carbon dioxide come out. The energy is stored and moved around in special molecules, while the carbon dioxide has to be removed from the cell, as it forms an acid if too much of it builds up. So in a way, aerobic bacteria “breathe in” oxygen and “breathe out” carbon dioxide. These bacteria evolved into complex animals by clustering together to form cells, tissues, organs, systems, and whole animal bodies. But since each cell still needs nutrients and oxygen for energy, the whole animal has to keep eating and breathing just to supply them.

read more on Ask Glenn  (London Science Museum)



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  • wartica: I can attest to this; eating garbage food , always lead me to eat more - all because I was lacking real nutrients . Great post and I look forward to s