Katy Thiessen

What is a cell?

Cells are the smallest structural and functional unit of an organism, 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. All cells have a cell membrane, DNA, cytoplasm, ribosomes, and ribosomes.


A prokaryote is single-celled organisms that lack a nucleus and internal parts and they cannot carry out many specialized functions. They are microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. Prokaryotes include the bacteria and cyanobacteria.


A eukaryote is an organism whose cells have a nucleus and contains internal parts and houses DNA. They are an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaebacteria.

Reproduction of Cells

Prokaryotes reproduce by a process that is called binary fission. The DNA in such cells is contained in a single circular chromosome called a plasmid within the cytoplasm. The reproductive process starts with the replication of the chromosome. The cell then fissions and forms two daughter cells.

Eukaryotes reproduce through the phases the interphase and cell division. During the interphase, the cell takes in nutrients, grows, and duplicates its chromosomes. During the cell division phase, the nucleus divides in a process called mitosis and then the divided nuclei are established in separate cells in a process called cytokinesis.