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The cell nucleus (from Latin nucleus or nuculeus 'kernel, seed'; pl.: nuclei) is a membrane-bound organelle found in eukaryotic cells.Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many.
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
The cells of plants, algae, fungi and most chromalveolates, but not animals, are surrounded by a cell wall. This is a layer outside the cell membrane, providing the cell with structural support, protection, and a filtering mechanism. The cell wall also prevents over-expansion when water enters the cell. [46]
Another structure identified within many nucleoli (particularly in plants) is a clear area in the center of the structure referred to as a nucleolar vacuole. [15] Nucleoli of various plant species have been shown to have very high concentrations of iron [16] in contrast to human and animal cell nucleoli.
Coenocyte of Sphaeroforma arctica Botrydium, showing a coenocytic body. A coenocyte (/ ˈ s iː n ə ˌ s aɪ t /) is a multinucleate cell which can result from multiple nuclear divisions without their accompanying cytokinesis, in contrast to a syncytium, which results from cellular aggregation followed by dissolution of the cell membranes inside the mass. [1]
Unlike the static nature typically depicted in textbooks, the plant cell nucleus is a highly dynamic structure, constantly moving around cells via actin networks and myosins. [1] The nucleus undergoes a characteristic program during cell division to guide asymmetric cell division, [ 2 ] but there are several stimuli that have been demonstrated ...
Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid.
The concentrated inner area is called the endoplasm and the outer layer is called the cell cortex, or ectoplasm. Movement of calcium ions in and out of the cytoplasm is a signaling activity for metabolic processes. [3] In plants, movement of the cytoplasm around vacuoles is known as cytoplasmic streaming.