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  2. Prokaryote - Wikipedia

    en.wikipedia.org/wiki/Prokaryote

    A prokaryote (/ p r oʊ ˈ k ær i oʊ t,-ə t /; less commonly spelled procaryote) [1] is a single-celled organism whose cell lacks a nucleus and other membrane-bound organelles. [2] The word prokaryote comes from the Ancient Greek πρό ( pró ), meaning 'before', and κάρυον ( káruon ), meaning 'nut' or 'kernel'. [ 3 ]

  3. Cell (biology) - Wikipedia

    en.wikipedia.org/wiki/Cell_(biology)

    Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes , and is the place where almost all DNA replication and RNA synthesis ( transcription ) occur.

  4. Cell physiology - Wikipedia

    en.wikipedia.org/wiki/Cell_physiology

    Typical eukaryotic animal cell structure. Eukaryotes have a nucleus where DNA is contained. They are usually larger than prokaryotes and contain many more organelles. The nucleus, the feature of a eukaryote that distinguishes it from a prokaryote, contains a nuclear envelope, nucleolus and chromatin.

  5. Cell biology - Wikipedia

    en.wikipedia.org/wiki/Cell_biology

    Prokaryotic cells are distinguished from eukaryotic cells by the absence of a cell nucleus or other membrane-bound organelle. [10] Prokaryotic cells are much smaller than eukaryotic cells, making them the smallest form of life. [11] Prokaryotic cells include Bacteria and Archaea, and lack an enclosed cell nucleus. Eukaryotic cells are found in ...

  6. Marine prokaryotes - Wikipedia

    en.wikipedia.org/wiki/Marine_prokaryotes

    Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, whereas prokaryotes are the organisms that do not have a nucleus enclosed within a membrane. [ 1 ] [ 2 ] [ 3 ] The three-domain system of classifying life adds another division: the prokaryotes are divided into two domains of life, the microscopic bacteria and the ...

  7. Extrachromosomal DNA - Wikipedia

    en.wikipedia.org/wiki/Extrachromosomal_DNA

    Although prokaryotic organisms do not possess a membrane-bound nucleus like eukaryotes, they do contain a nucleoid region in which the main chromosome is found. Extrachromosomal DNA exists in prokaryotes outside the nucleoid region as circular or linear plasmids.

  8. Three-domain system - Wikipedia

    en.wikipedia.org/wiki/Three-domain_system

    The three-domain system adds a level of classification (the domains) "above" the kingdoms present in the previously used five- or six-kingdom systems.This classification system recognizes the fundamental divide between the two prokaryotic groups, insofar as Archaea appear to be more closely related to eukaryotes than they are to other prokaryotes – bacteria-like organisms with no cell nucleus.

  9. Cytoskeleton - Wikipedia

    en.wikipedia.org/wiki/Cytoskeleton

    Intermediate filaments are most commonly known as the support system or "scaffolding" for the cell and nucleus while also playing a role in some cell functions. In combination with proteins and desmosomes , the intermediate filaments form cell-cell connections and anchor the cell-matrix junctions that are used in messaging between cells as well ...