==Eukaryotic cells== have a true nucleus (membrane-bound), have cells with membrane-bound organelles, are usually multi-cellular, and are usually visible to the naked eye.
==Prokaryotic cells== do not have a true nucleus, lack membrane-bound organelles, are always single-celled, and are always microscopic.
All living things belong to one of the following domains: ==bacteria, archaea, or eukarya.==
They are prokaryotic cells from various shapes, live in extreme environments, absorbs food, and have unique chemical characteristics.
An ==atom== is the smallest part of an element that displays the property of the element. It contains subatomic particles.
Each element is represented by one or two letters to give it a unique atomic symbol.
==Atomic mass== is located at the top left of an atomic symbol and ==atomic number== is located at the bottom left of the atomic symbol.
(These notes are from past Biology 120 lectures by Dr. Davenport at Reinhardt University as well as the textbook which the information comes from is linked below.) https://openstax.org/details/books/biology-2e
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