Replicated chromosomes, consisting of two sister chromatids held together at the centromere, have condensed and can be seen as stained bodies (chromo-somes). The developing embryo of any organism is a good tissue to examine for mitosis, since cells must divide at a high rate to transform a fertilized egg (single cell) into the trillions of cells of a viable organism.Ĭhromosomes are extended and not visible regions where rRNA is being transcribed stain dark and are termed nucleoli.
I NTERPHASE: Daughter cells grow in size and prepare for renewed mitosis.ĪNIMAL CELL DIVISION≾mbryonic blastula stage of whitefish In plant cells vesicles deposit new cell wall material along the equator to form the cell plate. The cell divides into two daughter cells (cytokinesis). Nuclear membrane forms around the chromosome clusters.Ĭhromosomes disappear from view as DNA re-extends, and nucleoli appear. This is like the reverse of prophase-the cell is returning to interphase.Ĭhromosomes (now single molecules of DNA with associated proteins) have reached opposite poles of the cell.
Prophase picture free#
The free ends of each chromosome trail back toward the equatorial plate and indicate movement. The kinetochore, a part of the centromere of each new chromosome, moves along a spindle fiber. Sister chromatids separate from each other and move to opposite poles of the cell. Metaphase ends when the centromeres of each pair of chromatids split apart. Some part of each chromosome is on this plate. The chromosomes assemble on the equatorial plate (an imaginary disc that crosses the center of the 3-dimensional cell). These radiations, called asters, are absent in plant cells. They radiate out to the plasma membrane at the poles in animal cells. Nuclear membrane breaks down and the chromosomes spread out. Prophase: Chromosomes become visible and nucleoli disappear (DNA + associated proteins become tightly organized).Ĭhromosomes consist of two sister chromatids (DNA replicas + associated proteins) attached together at a specialized region called the centromere.
G 2: DNA has been replicated cell is preparing for mitosis. S: DNA replication (S = synthesis new copies of DNA are synthesized.
What you can't see are the phases of interphase: G 1: Period of cell growth before (G = gap) ribosomes and organelles are being duplicated. The nucleus of the cell is clearly stained and appears to have tiny dots and one or more dark nucleoli inside. Farther up the root is the elongation zone, where cells are long rectangles these cells are not undergoing mitosis. This is the root meristem (embryonic tissue) where mitosis is occurring. PLANT CELL DIVISIONroot meristem of Allium cepa, the garden onionĮxamine the square cells just inside the root cap. Animal cells take a variety of different shapes at the end of mitosis, a neck forms to separate the two daughter cells. Note: Plant cells are often shaped like boxes because they are surrounded by a cell wall at the end of mitosis, the cell plate divides the two daughter cells. We see them shown in books as snapshots of a particular instant in the process you have to judge what was happening when the music stopped. Mitosis is a continuous process, and the phases blend into one another it can often be hard to tell if an image is in the late part of one phase or the early part of another. Mitosis, the actual process of dividing has four defined phases: Prophase, Metaphase, Anaphase, and Telophase then the daughter cells enter interphase. Most of the time a cell is in interphase, the growth and preparation stage of the cycle.
Prophase picture series#
The cell cycle refers to the continuing series of divisions alternating with cell growth: interphasemitosisinterphasemitosisinterphase. Cells multiply to make an organism bigger, to repair damage, or to multiply the number of organisms of that kind. A cell divides into two daughter cells tht are genetically identical to the original cell and to each other. Mitosis is the name for the kind of cell division that produces a greater number of cells = cell multiplication after division, the daughter cells are about half the size of their parent, and they grow before division occurs again. Wahlert & Mary Jean HollandĬELL CYCLE AND MITOSIS Nuclear and Cytoplasmic Division in the Eukarya
Cell Cycle and Mitosis, Laboratory Notes for BIO 1003 Laboratory Notes for BIO 1003 © 30 August 1999, John H.
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