Lysosomes – the Vacuums of the Cell
Enzymes are a type of protein that can speed up a chemical reaction in the body. While the body can still do the process without the enzyme, it may not be able to do it in time. Enzymes are responsible for many things, like digesting food and turning it into the energy that we can use for moving and living – this is called metabolism. Once ribosomes have created proteins and they’ve become enzymes, there has to be a place to hold them in the cell until they are needed for a body process. That’s where lysosomes come in.
If we remember ribosomes, we know they are on the ER or the Endoplasmic Reticulum. Once the ribosomes on the ER have created their proteins, the proteins get packaged up and sent to the Golgi apparatus. The Golgi apparatus is similar to the ER in that it is a bunch of folded up membranes and sacs. The difference between them is that while the ER is involved with ribosomes, the Golgi apparatus is responsible for making lysosomes. Once the proteins get to the Golgi apparatus, it makes them fully into enzymes and sends them, through lysosomes, out into the cell to begin their work.
Lysosomes are like suitcases in a cell – they use a membrane, or layer that some things can get into and others cannot, to hold enzymes so they can stay safely hidden away until the body needs them. Lysosomes are also a bit like garbage disposals – using the enzymes they hold inside their membrane, lysosomes break down food when it needs to be digested or unneeded parts of the body when they aren’t of use anymore.
Lysosomes prevent dead or unnecessary parts of cells, or even entire cells, from taking up space and causing problems for the body. If ribosomes were the construction workers of a cell, then the lysosomes could be considered the cleanup crew that comes after them and cleans up all the messes. Using the enzymes that come from the proteins that are created by ribosomes, they can work on digesting food, organelles, and old cells in the body. This is their only job, and while it seems like a simple one, it is very important and very specific. Not just any enzyme, or any lysosome, can do the job because food is very different from an organelle, and organelles are different from whole cells.
There are different kinds of lysosomes for different kinds of digestion because of this. Mainly, there are lysosomes that digest food that enters the cell, lysosomes that digest organelles – a special structure in a cell that can perform a specific function, like the Golgi apparatus or the ribosomes – that are no longer needed in a cell, and lysosomes that digest cells that are no longer needed in the body and have to be gotten rid of. The lysosome attaches to the thing that it needs to digest, drags it into the lysosome, and releases the enzymes inside of it to break down whatever object the lysosome attached to once it is fully inside.
Lysosomes can do this digestion because of the membrane mentioned earlier. Let’s say that a lysosome is a vacuum. Some vacuums, like lysosomes, are bigger or smaller, with different attachments, for use in different areas of a house. In this case, the house is your cell, and the messes in the house are the things that the lysosomes must digest, with the lysosome being the vacuum. With a vacuum, only certain things can fit inside it. If you tried to use a vacuum to pick up a football, it wouldn’t fit! But it might be able to pick up a balled-up piece of paper. This is because the membrane of a lysosome only lets certain things in and out of it, and is only used for a certain job because of this feature. A hand-held vacuum wouldn’t be able to clean a whole house, after all, but it may be great for cleaning a single chair.
If the way a lysosome works is still hard to understand, that’s okay. A lot of what the membrane does can be understood best by learning about active and passive transport, a lesson that will be coming to you very soon.
