eukaryote is an abundant and diverse organism that lacks membrane bound organelles.
eukaryote is an abundant and diverse organism that lacks membrane bound organelles.
abundant and diverse organisms that lack membrane bound organelles?
eukaryote
there are two primary types of cells. prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular dna and ribosomes. bacteria and archaea are two domains of prokaryotes. the other primary type of cells are the eukaryotes, which have distinct nuclei bound by a nuclear membrane and membrane-bound organelles, including mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, and vacuoles. in addition, they possess organized chromosomes that store genetic material. all species of large complex organisms are eukaryotes, including animals, plants and fungi, though most species of eukaryote are protist microorganisms. the conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell.
life
a second, less restrictive definition of organelles is that they are membrane-bound structures. however, even by using this definition, some parts of the cell that have been shown to be distinct functional units do not qualify as organelles. therefore, the use of organelle to also refer to non-membrane bound structures such as ribosomes is common and accepted. this has led many texts to delineate between membrane-bound and non-membrane bound organelles. the non-membrane bound organelles, also called large biomolecular complexes, are large assemblies of macromolecules that carry out particular and specialized functions, but they lack membrane boundaries. many of these are referred to as "proteinaceous organelles" as there many structure is made of proteins. such cell structures include:
organelle