Are red blood cells alive?

Callum Campbell

Red blood cells are pretty important, as cells go. They do more than just make your blood a red colour – these donut-disk-shaped cells are in charge of transporting oxygen all around your body. In a way they’re like delivery drivers, except their cargo is both essential to life and also very dangerous to it at the same time… Let’s think about that for a moment. What’s it like to be the one in charge of all the oxygen?

Oxygen and life

Picture a massive cinema-style fiery explosion destroying a whole building. Oxygen did that. Explosions happen when very flammable substances react violently with oxygen in a split second, releasing loads of energy in the process. In a sense, your cells make their own energy by creating tiny tiny tiny tiny tiny explosion reactions (called combustion reactions) inside the cell. They react glucose (sugar) with oxygen. This process is done very carefully, step by step by step, so only a bit of energy is released at any one moment. This way the cell gets its energy but isn’t damaged at the same time. Without this bit of biochemistry (called respiration) all your cells would have no energy, and they’d die.

Now cut to the red blood cell. If this cell messes up its delivery, all the other cells die, right? BUT if it doesn’t take good care of the oxygen, it will react with the cell uncontrollably in a combustion reaction that will damage the cell beyond repair! In this sense a red blood cell is a bit like a delivery driver with a truck full of dynamite. To minimise the risk to itself from carrying oxygen, red blood cells are a bit different to normal cells on the inside. Let’s take a closer look at them…

Red blood cells vs other cells

On the inside of almost all of your cells you’ll find lots of structures called organelles. Organelles are a bit like tiny cell organs, and each one is in charge of one big job. For example, mitochondria are in charge of making the cell’s energy by reacting glucose with oxygen. Another organelle, the nucleus, uses DNA to tell the cell what to do, when to do it, and to control cell division.

Unlike most cells, red blood cells don’t have any organelles. None at all. This is because organelles are extremely vulnerable to oxygen damage, so inside a red blood cell they’d never survive. Instead of organelles, red blood cells are absolutely PACKED with something called haemoglobin. Haemoglobin is the molecule in charge of holding the oxygen and keeping it safe. Without haemoglobin, all the free oxygen would violently react with the cell like we talked about earlier.

But what are the consequences of having no organelles? Does this have an impact on whether a red blood cell is ‘alive’? Well, in short, yes it does. Having no organelles means that red blood cells can’t make their own proteins, or their own lipids, or (much of) their own energy, or even divide like most cells can. In a way, a red blood cell is really just a big bag of haemoglobin made in the bone marrow and floating around in the blood. So if being ‘alive’ means that a cell can do lots of things for itself and can divide to make new cells, then a red blood cell isn’t really alive at all. But if being ‘alive’ means that a cell can perform an important task and is essential to the survival of the organism, then a red blood cell is one of the most alive cells in the whole body – we sure couldn’t live without them. Thanks little red guys!