Cell waste: A cell with a vacuole
Cell waste and vacuoles
Soon after eukaryote cells began to make vacuoles to help them catch their food and store it, about 600 million years ago, the cells also began to use the vacuoles to get rid of garbage in the cell – molecules that the cell didn’t need anymore. If the cell used photosynthesis, this would be mainly extra oxygen; if it didn’t, the garbage would be mainly extra carbon dioxide.
How cells evolved
Parts of a cell
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Like an airlock on a spaceship
The cell got rid of garbage by bringing the garbage close to the cell membrane and then closing the cell membrane around the garbage, isolating it from the rest of the cell. Then the cell could open the cell membrane on the outside of the cell, letting the garbage out without losing any cytoplasm or letting anything else in. It’s like an airlock on a spaceship, or like the double doors at the supermarket that keep the hot air inside the supermarket and the cold air outside.
More about cell membranes
Lysosomes and cell excretion
Lysosomes also play a part in getting rid of garbage in a cell. If there are old worn-out parts in a cell, or too many mitochondria, or poisons, then the lysosome forms a membrane bubble around them, and the enzymes inside the lysosome break these large parts down into small molecules that can fit to get through the cell membrane. Then the lysosome floats through the cytoplasm over to the cell membrane and uses the same air lock method to get the garbage out of the cell.
More about lysosomes
Did you find out what you wanted to know about cell waste and excretion? Let us know in the comments!
Learn by doing: Soap bubbles and vacuoles
Bibliography and further reading about vacuoles:
what are vacuoles then. dont they also dispose waste??
Yes, Raju. As the article says, vacuoles do get rid of waste. Lysosomes help us get rid of bigger molecules that have to be broken up in order to fit inside a vacuole.
Ok but what happens next? Does it go to the blood directly? And if so through what?
Where the waste goes after the cell pushes it out depends a lot on what kind of cell it is. For most cells, they’re just one-celled creatures living in the ocean, so the waste just goes into the ocean. In your body, the waste might go directly from the cell into your blood, or into your intestines, or your lymphatic system – there are a lot of ways your body moves things around.