Microvilli are prominent in cells that - in cells that absorb substances like in the intestine. Microvilli contain bundles of - of microfilaments that are anchored to the terminal web, that runs just below cells surface Cell cycle - cell division Cell cycle is divided into - two time frames. Interphase and Cell Division Interphase - Cell is not dividing cell division includes - Mitosis and cytokinesis Interphase is composed of - G1 - growth S - synthesis G2 - G1 of Interphase - cell conduct regular activities. prepares for DNA replication, begins to replicate organelles, including centrioles. typically 8 hours. speed depends on cell, skin cells have fast G1 phase. G0 of interphase - cells that never divide. nerve cells S phase of Interphase - DNA replicates. Typically 6-8 hours G2 interphase - produce enzymes needed for division. Centriole replication, started in G1, has now completed. 2-5 hours After interphase comes - M phase. Mitosis overall 1 - 3 hours Mitosis provides - cellular reproduction, increase numbers, provides growth, wound healing, and remodeling. Mitosis consists of phases - Prophase Metaphase Anaphase
Telophase Prophase early - chromatin in nucleus become highly coiled, condens into chromisomes. each chromisome consists of two identical chromatids held together by centromere. Also Mitotic spindle forms. Prophase late - Centrioles migrate to opposite ends of cells, nuclear membrane breaks, spindles completed metaphase - Chromosomes line up along equator forming metaphase plate. Miotic spindle attach to centromeres Kinetochores (dna protein complex on centromere) Anaphase - chromatid pairs separate, pulled to opposite ends as spindles shorten. telophase - nuclear membrane forms around each new set of chromosomes. nucleus forms, micro spindles disappear. Cytokinesis - during late anophase, cell clevages, squeezes, pinches two new cells apart.