PROPHASE EXAMPLE FREE

PROPHASE EXAMPLE FREE

The mitotic spindle microtubules are now free to enter the nuclear region, and formation of specialized protein complexes called kinetochores begins on each centromere. The nucleolus also disappears during this period. During this period the chromosomes continue to condense and gradually shorten and thicken until they have completely formed the units that will undergo mitosis. Late prophase, or prometaphase begins with the disruption of the nuclear envelope, which is broken down into small membrane vesicles that closely resemble the endoplasmic reticulum and tend to remain visible around the mitotic spindle.

The photomicrograph below depicts the initial chromosome condensation at the beginning of prophase (early prophase) when the nucleolus is still intact. During prophase, the cytoskeleton (composed of cytoplasmic microtubules) begins to disassemble and the main component of the mitotic apparatus, the mitotic spindle begins to form outside the nucleus at opposite ends of the cell. The first phase of mitosis is known as the prophase, where the nuclear chromatin starts to become organized and condenses into thick strands that eventually become chromosomes. Centromeres are crucial to segregation of the daughter chromatids during mitosis.

Before the cell enters the mitosis phase, it first undergoes a synthesis or S phase where each chromosome is duplicated and consists of two sister chromatids joined together by a specific DNA sequence known as a centromere. In the future, we hope to obtain higher quality images.Ī normal resting cell exists in a state called interphase in which the chromatin is undifferentiated in the heavily-stained nucleus, as illustrated above. We apologize for the poor quality of the photomicrographs in this section, but it was built using pre-prepared (stained and mounted) microslides that we obtained commercially. In this part of the Photo Gallery, we illustrate the various steps in mitosis that occur in onion root tips, which are relatively easy to capture in all stages. This, coupled with cytokinesis (division of the cytoplasm), occurs in all multicellular plants and animals to permit growth of the organism. Mitosis is the mechanism that allows the nuclei of cells to split and provide each daughter cell with a complete set of chromosomes during cellular division. Observing Mitosis with Fluorescence Microscopy - Digital imaging with fluorescence microscopy is becoming a powerful tool to assist scientists in understanding the complex process of mitosis on both a structural and functional level. Mitosis Learn the steps in mitosis with our mitosis interactive Java tutorial Molecular Expressions Photo Gallery: Mitosis

Prophase example