by123 chapter 12 - Chapter 12: M i tosis Cell division-...

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Chapter 12: Mitosis Cell division- reproduction of cells ROLES OF CELL DIVISION o Reproduction, growth and development, and tissue renewal Genome- the genetic material of a organism; the complete complement of an organism’s genes along with its noncoding nucleic acid sequences Chromosomes- a cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins. Somatic cells- all body cells except the reproductive cells. They each contain 46 chromosomes made of two sets of 23 Gametes- reproductive cells. They each contain one set of 23 chromosomes. Chromatin- a complex of DNA and associated protein molecules. Makes up chromosomes When a cell is not dividing, and even as it duplicates its DNA in preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber. After DNA duplication, however, the chromosomes condense: each chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and so thick you can see them with a light microscope. Each duplicated chromosome has two sister chromatids Sister chromatid cohesion- the attachment of sister chromatids by adhesive protein complexes called cohesins Centromere- a specialized region where two chromatids are most closely attached Mitosis- the division of the nucleolus Cytokinesis- the division of the cytoplasm; follows mitosis Mitotic spindle- structure consisting of fibers made of microtubules and associated proteins, which begins to form in the cytoplasm during prophase. Includes the centrosomes, the spindle microtubules, and the asters. o Starts at the centrosome, a subcellular region containing material that functions throughout the cell to organize the cell’s microtubules. A pair of centrioles is at the center of the centrosome o Aster- a radial array of short microtubules that extend from each chromosome. o Kinetochore- a structure of proteins associated with specific sections of chromosomal DNA at the Centromere
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Kinetochore microtubules- the spindle microtubules that attach to the kinetochores. They help line up chromosomes. Kinetochore microtubules attach to chromosomes, and the chromosome begins to move toward the
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This note was uploaded on 08/07/2009 for the course BY 123 taught by Professor Cusic during the Spring '07 term at University of Alabama at Birmingham.

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by123 chapter 12 - Chapter 12: M i tosis Cell division-...

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