Biol Test 3 Notes

Biol Test 3 Notes - Biology Growth and Repair How do cells...

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Biology Growth and Repair: How do cells reproduce? - Cells need to possess the genetic material characteristic of the organism o Genetic material is DNA o The “daughter” cells need the complete genetic complement - Prokaryotes o Circular strands of DNA o Replicate the DNA and pass it on to the “daughter” cells o Divide by binary fission - Eukaryotes o A problem o Genetic material is found in linear chromosomes Linear strands of DNA complexed with proteins Multiple chromosomes (ex: humans 46) o How to insure that each daughter cell gets the complete set of chromosomes? How do you get identical daughter cells? Need a mechanism to allow each daughter cell to have a copy of each chromosome o The solution: daughter cells to receive identical chromosomes Mitosis o Cell Division: Mitosis Reproductions Growth Repair Produce “daughter” cells that have identical genetic complements Occurs in somatic cells o Somatic Cells
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Biology All body cells except cells which give rise to gametes o Chromosomes Found in the nucleus of the cell Linear strand of DNA o Chromatin The long linear strand of DNA and complexed proteins o Duplicated Chromosome Consists of two sister chromatids Identical copies of DNA Attached at a specialized region called the centromere - Cell cycle o Interphase Generally 90% of the cell cycle Gap 1 (G1) Synthesis of cell components Increase in number of organelles S phase Synthesis (replication) of DNA Doubling of the genetic material Gap 2 (G2) Centrioles replicate in animals Structure for cytokinesis put in place o Mitotic Phase Mitosis Cytokinesis
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Biology o Centrioles In animals 9 sets of triplet microtubules arranged in a ring Found in the centrosome A region from which microtubules grow out Help organize microtubule growth, but centrioles are not necessary o Mitosis Prophase Nucleoli disappear Chromatin condenses Mitotic spindle forms from microtubules in cytoplasm Centrosomes move away from each other Prometaphase Nuclear envelope fragments Microtubules of spindle invade the nuclear region and interact with the chromosomes via the kinetochore o Kinetochore Structure of proteins specific sections of chromosomal DNA at the centromere Point of attachment for microtubules of the spindle o Mitotic Spindle Formed from microtubules extending from the two centrosomes As centrosomes move away from each other the microtubules lengthen Metaphase Centrosomes at opposite poles
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Biology Chromosomes arranged at the midplane of the spindle Anaphase Sister chromatids separate and move toward the poles Telophase Nuclear membrane forming again in two chromosomes Chromosomes de-condense Two new chromosomes - Cell division for gamete formation o Sexual reproductions Fusion of gametes from parents to form a zygote Greater diversity of offspring than asexual reproduction
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Biol Test 3 Notes - Biology Growth and Repair How do cells...

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