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test two notes - The Cell Cycle 23:47 Cell Function: the...

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The Cell Cycle 23:47 Cell Function : the most basic function  to duplicate accurately the DNA  in the chromosomes and then segregate the copies into identical daughter cells Unicellular Organism: division creates an entire new organism Multi-cellular: division for development from a fertilized cell, growth and repair Cell Cycle  cell division is an important part Passing identical genetic material to cellular offspring is a crucial function of cell  division Definitions     Genome     : genetic information, DNA in a cell makes the cells genome Chromosomes     : how DNA is packaged Somatic Cells     : all body cells except reproductive cells Gametes     : sperm and eggs Chromatin     : chromosomes are made of these Centromere     : waist of the chromosome Mitosis     : division of the nucleus Cytokinesis     : division of cytoplasm Humans have 46 chromosomes, 23 from each parent Meiosis     : creates eggs and sperm Phases of Cell Cycle Mitotic (M) phase--- mitosis and cytokinesis
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Interphase—cell growth and copying of chromosomes in preperation for cell  division Interphase (about 90% of cell cycle) o G1 phase- first gap, cell grows o S phase- synthesis, copies chromosomes Separated in time from mitosis (G1 and G2) o G2 phase- second gap, grows more and prepares for division Growth in all 3 phases, duplicate chromosomes in S only Mitotic Phase Mitosis Prophase: chromatin fibers condense,
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Can see the chromosomes Pro-metaphase: Can see the chromosomes more clearly and the spindle starts to  form Metaphase Chromosomes line up and centrosomes are at opposite poles Anaphase Sister chromatids seperate Telophase  Two diff nuclei form Cytokinesis Occurs by a process called cleavage Cleavage furrow: shallow groove in the cell surface near the old  metaphase plate Questions How is the length of a cell cycle determined? o The time needed from the completion of one cell division to the completion  of the next Some are fast- tumors, some slow- neurons o Look at a population  how long it takes to double How do you determine the length of each of the parts of the cycle: G1, S,  G2 and M? o M observation, take the time it takes for a population to double then M is  10% of the total time o S  DNA replication. 
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DNA- Thymidine RNA- Uracil Look to see what cells have thymidine to determine which ones are in  S, % of cell cycle it takes is even to the % of cells with H-Thymidine If a cell is just starting S its going to pick up tribuated thymidine o G2
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This note was uploaded on 05/09/2010 for the course BSCI 105 taught by Professor Jensen during the Spring '07 term at Maryland.

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test two notes - The Cell Cycle 23:47 Cell Function: the...

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