Cell City
All living organisms are made up of cells, from the single-celled bacteria to ourselves with up to a whopping 40 trillion cells!
Cells are described as the building blocks of life, but not all cells look alike. For example, the neuron cells in our spinal column that stretch for up to one metre look very different to the packed epithelial cells that line the insides of our organs. Whilst these cells may look very different the basic machinery inside them is remarkedly similar.
A cell, with all its this basic machinery, could be compared to some of the important features you would find in your city or town…
Below we explain how each of the compartments in a cell compare to the important features of our Cell City.
Nucleus & DNA: DNA can be thought of as a vast collection of books, or instruction manuals (genes) that describe how to build a cell. The DNA is housed in the nucleus where, like in a library, it is carefully arranged and organised.
Mitochondria: As in a city, all the jobs a cell must do require energy. One of the main jobs of mitochondria is the produce energy. Whilst the power station may burn fossil fuels, the mitochondria ‘burn’ oxygen in this process.
Plasma membrane: A layer of lipids that mark the edge of the cell, which contains proteins that act as signposts to send and receive messages from other cells. The membrane, like a city boundary, is highly dynamic!
Microtubules: The main highways for fast transport through the cell are the microtubules. However, this are not roads for the faint-hearted as they can be constantly growing and shrinking, and even undergo catastrophe where they collapse!
Lysosome: The job of the lysosome is waste processing. They breakdown proteins and lipids that are damaged or on longer needed, like dirty water in a water works, so their building blocks can be recycled and reused.
Golgi: It is essential that the newly made proteins get to the correct place in the cell. Like a warehouse, the Golgi apparatus sorts the proteins and adds on carbohydrates that are important for the function of the protein and also can act as an address label.
Endoplasmic reticulum (ER): One reason that our diets are made up of proteins, fats (lipids) and carbohydrates is because these are the building blocks of our cells. The ER and ribosomes are the factories that make proteins of different sizes, shapes that do different jobs.
Actin: The edge of a cell has a layer of highly branched actin, making it an extremely complex city wall. However, unlike a wall in a city it is movable, allowing things in and out of the cell. It also pushes against the city limits so the cell can change shape and move.