Biology 1201 Notes for 3rd Exam(Lauren)

Biology 1201 Notes for 3rd Exam(Lauren) - Biology 1201...

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Biology 1201 Notes for 3 rd Exam (Began March 3, 2009) Growth and repair: How do cells reproduce?. .. Cells need to possess the genetic material characteristic of the organism Genetic material is DNA The “daughter” cells need the complete genetic complement CLICKER : The genetic material of Prokaryotes is: Circular DNA Prokaryotes Circular strands of DNA Replicate the DNA and pass it on to the “daughter” cells Divide by binary fission Fig. 12.11 -Bacterial cell division (binary fission) Eukaryotes A problem Genetic material is found in linear chromosomes o Linear strands of DNA complexed with proteins o Multiple chromosomes (e.g., humans 46) 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 The solution A process call mitosis Cell Division: Mitosis Reproduction Growth Repair Produce “daughter” cells that have identical genetic complements Occurs in somatic cells Somatic Cells All body cells except cells which give rise to gametes Chromosomes A complex of a linear strand of DNA and protein Each eukaryotic species has a characteristic number Found in the nucleus Chromatin The long linear strand of DNA and complexed proteins Duplicated chromosome Consists of two sister chromatids Identical copies of DNA Attached at a specialized region called the centromere Fig. 12.4 -Chromosome duplication and distribution during mitosis CLICKER: How many centromeres per chromosome? 1 CLICKER : How many centromeres per chromosome consisting of 2 sister chromatids? 1 Fig. 12.5 -The cell cycle Cell Cycle Interphase o Generally 90% of the cell cycle o Gap 1 (G1)
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Synthesis of cell components Increase in number of organelles o S Phase Synthesis (replication) of DNA Doubling of the genetic material o Gap2 (G2) Centrioles replicate in animal cells 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 Most plants lack centrioles (higher plants) Structure for cytokinesis put in place Mitotic Phase 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 and specific sections of chromosomal DNA at the centromere Point of attachment for microtubules of the spindle Mitotic Spindle Formed from microtubules extending… Metaphase Centrosomes at opposite poles Chromosomes arranged at the midplane of the spindle Anaphase
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Biology 1201 Notes for 3rd Exam(Lauren) - Biology 1201...

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