There are two type of Endoplasmic reticlum (ER). Ribosomes after production from the nucleus are released into the cytoplasm and either float or attach to the endoplasmic reticulum. Outside the nucleus the cytoplasm contains all other cell organelles floating in its fluid. The nucleoulus produce ribosomes which have the function of synthesis of proteins. The DNA consists of chromatin which is the tangled spread form of DNA in the nuclear membrane. The nucleus contains the DNA which dictates cell replication. The cell structure and function is usually described using the eukaryotic cell. While prokaryotic cells are usually single called organisms such as bacteria, eukaryotic cells are usually multicellular organisms. Both cells however have a cell membrane which holds and separates the cell from its external environment, a cytoplasm which is all of the cell material enclosed by the membrane and a nucleiod containing genetic material which is the DNA.

Including prokaryotic (simple structure with no membrane bound organelles) and eukaryotic (complex structure with membrane bound organelles) cells. Usually cells are microscopic which means they can not be seen with the naked eye.

Which means an organism can consist of a single cell or multiple cells. Cells are the smallest structural and functional units of an organism.

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