equatorial division

(noun)

a process of nuclear division in which each chromosome divides equally such that the number of chromosomes remains the same from parent to daughter cells

Related Terms

Examples of equatorial division in the following topics:

  • Comparing Meiosis and Mitosis

    • Mitosis and meiosis are both forms of division of the nucleus in eukaryotic cells.
    • The nuclei resulting from a mitotic division are genetically identical to the original nucleus.
    • For this reason, meiosis I is referred to as a reduction division.
    • Meiosis II is much more similar to a mitotic division.
    • Meiosis II is, therefore, referred to as equatorial division.

  • Meiosis I

    • In nearly all species of animals and some fungi, cytokinesis separates the cell contents via a cleavage furrow (constriction of the actin ring that leads to cytoplasmic division).
    • Two haploid cells are the end result of the first meiotic division.
    • In this case, there are two possible arrangements at the equatorial plane in metaphase I.

  • The Mitotic Phase and the G0 Phase

    • The first portion of the mitotic phase is called karyokinesis or nuclear division.
    • Karyokinesis, also known as mitosis, is divided into a series of phases (prophase, prometaphase, metaphase, anaphase, and telophase) that result in the division of the cell nucleus .
    • During metaphase, the "change phase," all the chromosomes are aligned in a plane called the metaphase plate, or the equatorial plane, midway between the two poles of the cell.
    • Cytokinesis, or "cell motion," is the second main stage of the mitotic phase during which cell division is completed via the physical separation of the cytoplasmic components into two daughter cells.
    • Division is not complete until the cell components have been apportioned and completely separated into the two daughter cells.

  • Gene Expression in Stem Cells

    • Symmetric division maintains stem cell lines and asymmetric division yields differentiated cells.
    • Stem cells are undifferentiated biological cells found in multicellular organisms, that can differentiate into specialized cells (asymmetric division) or can divide to produce more stem cells (symmetric division).
    • This mechanism is known as extrinsic asymmetric cell division.
    • The term asymmetric cell division usually refers to such intrinsic asymmetric divisions.
    • This diagram illustrates stem cell division and differentiation, through the processes of (1) symmetric stem cell division, (2) asymmetric stem cell division, (3) progenitor division, and (4) terminal differentiation.

  • Tropical Wet Forest and Savannas

    • Tropical wet forests, also referred to as tropical rainforests, are found in equatorial regions .
    • Tropical wet forests are depicted in green and are usually found at equatorial regions.

  • The Role of the Cell Cycle

    • Trillions of cell divisions subsequently occur in a controlled manner to produce a complex, multicellular human.
    • Single-celled organisms use cell division as their method of reproduction.
    • But what triggers a cell to divide and how does it prepare for and complete cell division?
    • Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages of growth, DNA replication, and division that produces two identical (clone) cells.
    • After four rounds of cell division, (b) there are 16 cells, as seen in this SEM image.

  • Introduction to Meiosis

    • Meiosis is the nuclear division of diploid cells into haploid cells, which is a necessary step in sexual reproduction.
    • Therefore, sexual reproduction includes a nuclear division that reduces the number of chromosome sets.
    • Haploid cells that are part of the sexual reproductive cycle are produced by a type of cell division called meiosis.
    • Thus, meiosis I is the first round of meiotic division and consists of prophase I, prometaphase I, and so on.
    • Meiosis II, the second round of meiotic division, includes prophase II, prometaphase II, and so on.

  • Regulation of the Cell Cycle by External Events

    • External factors can influence the cell cycle by inhibiting or initiating cell division.
    • Both the initiation and inhibition of cell division are triggered by events external to the cell when it is about to begin the replication process.
    • A lack of HGH can inhibit cell division, resulting in dwarfism, whereas too much HGH can result in gigantism .
    • Crowding of cells can also inhibit cell division.
    • Another factor that can initiate cell division is the size of the cell; as a cell grows, it becomes inefficient due to its decreasing surface-to-volume ratio.

  • The Major Divisions of Land Plants

  • Types of Root Systems and Zones of Growth

    • The root tip has three main zones: a zone of cell division, a zone of elongation, and a zone of maturation.
    • The root tip can be divided into three zones: a zone of cell division, a zone of elongation, and a zone of maturation .
    • The zone of cell division is closest to the root tip and is made up of the actively-dividing cells of the root meristem, which contains the undifferentiated cells of the germinating plant.
    • A longitudinal view of the root reveals the zones of cell division, elongation, and maturation.
    • Cell division occurs in the apical meristem.