Think back to when you were younger, staring up into the night sky looking at all the starts laid out in front of you. It seemed like the world was endless and there were more stars than what could be measured. Now imagine taking all of those stars one by one like legos and start building them into life. You could take every star in the night sky turn them into atoms and you would not have enough particles to build an adult human. An adult human at about 150 pounds has more than 7,000,000,000,000,000,000,000,000,000 atoms, the universe only has roughly a measly 10,000,000,000,000,000,000,000 stars. To put this in perspective, if you took 100 million (100,000,000) atoms and turned them into a chain it would only be about 1cm long.
So what is an atom? An atom is the smallest unit of matter, now this is not to be confused with the smallest unit of life, which we will get to later. Atoms are composed of protons, neutrons and electrons, the number of electrons and protons are equal and determine which properties it has. A bunch of the same atoms together is a pure substance, they are known as elements (ex. Hydrogen, oxygen, nitrogen…) there are over 100 elements known but only about 24 of them are commonly found in living organisms. When many elements bind together it creates a molecule (ex water, carbon dioxide…). Many molecules put together can form many different things, but most importantly, they can work together to form something magical: a cell.
What is so special about a cell? A better question would be: what isn’t special about a cell? A cell is the smallest unit of life, it is essential to everything we are! There are two main types of cells: Prokaryotic and Eukaryotic. Both types have three things in common, a plasma membrane, a DNA containing region, and cytoplasm.
Prokaryotic cells, sounds fancy, what are they? To much surprise, Prokaryotic cells are not that fancy at all. They are the simpler cells, and are representative to single celled organisms like bacteria and archaea. Prokaryotic cells are directly known as “before the nucleus” they are the smallest unit of life. Prokaryotic cells have a cell wall-to protect the plasma membrane and structure, flagellum-for locomotion, and phili-to aid in moving across surfaces.
Eukaryotic cells are the fancy cells. They are the cells that contain a nucleus. A nucleus is like a control center, it contains all the vital information, a top secret lair for DNA. Eukaryotic cells are responsible for animal life (human included) and plant life. They are much more complex and contain organelles which are specialized units within a cell that carry out a specific task. The main difference between plant and animal cells are slight. Plant cells contain a cell wall, a central vacuole, and chloroplasts, where animal cells do not. There are other slight differences but these are the main notable ones.
With all of this being said not one cell is more important than the other, without the prokaryotic cells we would not have had the formation of the eukaryotic cells and both types of cells rely on the other to function and live in harmony (homeostasis). Cells, the smallest unit of life, are remarkable things, and to think we are all just a really lucky combination of atoms, held together by some mysterious force of nature!