Search results
Results from the WOW.Com Content Network
Prophase is the first stage of mitosis in animal cells, and the second stage of mitosis in plant cells. [10] At the start of prophase there are two identical copies of each chromosome in the cell due to replication in interphase. These copies are referred to as sister chromatids and are attached by DNA element called the centromere. [11]
The mitosis process in the cells of eukaryotic organisms follows a similar pattern, but with variations in three main details. "Closed" and "open" mitosis can be distinguished on the basis of nuclear envelope remaining intact or breaking down. An intermediate form with partial degradation of the nuclear envelope is called "semiopen" mitosis.
English: A diagram of mitosis stages Interphase (G₂): In this substage, the cell prepares for nuclear division and a protein that makes microtubles for cell division is synthesized. Prophase: The longest stage of mitosis. In this stage the chromosomes become visible and the centrioles separate and move to opposite poles of the cell.
English: Stages of early mitosis in a vertebrate cell. Scanning electron microscopy reveals that sister-chromatid pairs first condense into single rod-like structures during prophase. As mitosis proceeds, chromatid arms are gradually resolved and become almost completely distinct by the end of metaphase. Kindly provided by Adrian T. Sumner.
Cell division in prokaryotes (binary fission) and eukaryotes (mitosis and meiosis). The thick lines are chromosomes, and the thin blue lines are fibers pulling on the chromosomes and pushing the ends of the cell apart. The cell cycle in eukaryotes: I = Interphase, M = Mitosis, G 0 = Gap 0, G 1 = Gap 1, G 2 = Gap 2, S = Synthesis, G 3 = Gap 3.
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
Role of the centrosome in cell cycle progression. Centrosomes are associated with the nuclear membrane during the prophase stage of the cell cycle. During mitosis, the nuclear membrane breaks down, and the centrosome-nucleated microtubules can interact with the chromosomes to build the mitotic spindle.
Arresting mitosis in metaphase by a solution of colchicine; Squashing the preparation on the slide forcing the chromosomes into a single plane; Cutting up a photomicrograph and arranging the result into an indisputable karyogram. The work took place in 1955, and was published in 1956. The karyotype of humans includes only 46 chromosomes.