Cells

What is a cell?

What is a cell?

A cell is the smallest structural and functional unit of an organism. It is typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane. Microscopic organisms typically consist of a single cell, which is either eukaryotic or prokaryotic.

What all do cells share?

All living things use DNA as genetic material. Viruses are also able to use RNA, but their position as an organism is highly debated. The plasma membrane is at least one phospholipid bilayer with embedded proteins for stability, communication and import and export of nutrients. The cytoplasm is the liquid material of the cell that contains membrane-bound organelles in eukaryotes. Inside the cytoplasm and embedded certain organelles are ribosomes. They are responsible for protein synthesis.

What is a prokaryote?

A prokaryote is a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. Prokaryotes include the bacteria and cyanobacteria. Most prokaryotes are tiny single cells, others can form larger multi-celled structures. Prokaryotes have been utilized as sources of enzymes that work under extreme conditions. Prokaryotic cells are divided into Bacteria and Archaea. Bacteria is the most familiar prokaryote. Bacteria is a very diverse group that has several shapes depending on the species. As for Archaea, they are also diverse but resemble the bacteria in general appearance. The domain Archaea, can live in extreme environments.

What is a eukaryote?

A eukaryote is an organism with a complex cell or cells in which genetic material is organized into a membrane-bound nucleus or nuclei. Eukaryotes do not have prokaryotes or a nucleus, they comprise animals, fungi, and plants. Eukaryotes are often treated as a domain, super-kingdom, or empire. Eukaryotes are more recent among life on Earth than prokaryotes.

Similarities of Prokaryotes and Eukaryotes


  • They both have DNA as a genetic material
  • They are both membrane bound
  • They both have ribosomes
  • They both have similar metabolism
  • They are both diverse in forms

Differences of Prokaryotes and Eukaryotes

Eukaryotes:


  • have a nucleus
  • have membrane-bound organelles
  • cells are ten times the size of prokaryotes
  • the DNA is much more complex and much more extensive
  • the DNA is held within the nucleus and is associated with proteins



Prokaryotes:


  • have a cell composed of peptidoglycan, a single large polymer of amino acids and sugar.
  • the DNA floats freely around the cell
  • live a wide variety of environments
  • all cells have a cell wall
  • are all bacteria