Test 2 Review Packet

Test 2 Review Packet - BISC11 REVIEW 1 BIOLOGY TEST 2...

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BISC11 REVIEW 1 BIOLOGY TEST 2 REVIEW PACKET SECTION ONE: Cell Division, Mitotic and Meiotic Cycles. MEOISIS: Mitotic Cell Division: discovered by Walther Flemming in 1882. - Reasons for mitotic cell division: 1. Repair and renewal: lysosomes can break down cells, but to replace these cells need to perform meiosis. Ex. Liver cells, bone marrow cells continuously produce new blood cells, Skin is always schlepping off dead skin cells and making new ones. 2. Growth 3. Reproduction: creating new individuals. Embryonic development. Fertilize an egg, that egg divides by mitotic cell division to create a multicellular organism. - Mitotic Cell Cycle Overview: o Interphase: cell growth and DNA synthesis, 90% of cycle. G1: first gap G2: second gap S: DNA synthesis and duplication of chromosomes. o Mitotic Phase: shortest part. Mitosis: karyokinesis or nuclear division. Cytokinesis: cytoplasmic division G PHASE, G2 PHASE S PHASE Chromosome duplication: cell starts off with 1 chromosome consisting of 2 chromatid. After DNA synthesis, chromatid is replicated to 2 chromatids but 1 chromosome. M PHASE Directly after G2, consists of prophase thru telophase.
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BISC11 REVIEW 2 PROPHASE: - Centrosomes start to move away from each other - Mitotic spindle begins to form, composed of the centrosomes and microtubules. - Chromosomes start to condense and fold on itself and are visible with light microscope. PROMETAPHASE: - nuclear envelope breaks down into pieces - microtubules extend from each other: - Kinetechore microtubules: connect to kinetechore. - Others go from centrosomes to other centrosomes. - Non kinetechore microtubules. - Astermicrotubules: each centrosomes have little microtubules that go no particular direction. METAPHASE: - chromosomes line up on the “metaphase plate” - Centrosomes are at opposite poles of cell. - For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubules. - Mitotic spindle ** - Longest stage of mitosis. ANAPHASE: - Cohesin proteins are cleaved - each chromosome has 2 chromatids, chromatids start to separate and move apart. - Cell elongates.
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BISC11 REVIEW 3   CYTOKINESIS:  Plant Cells : form vesicles that contain cell wall material that eventually fuse together and create a cell plate which lengthens and separates 2 cells with cell wall and cell surface membrane. Animal cells : cleavage furrow has ring of microfilaments that pinch off cells. ** uses microfilaments, not microtubules like other phases. *** only difference in nuclear division: plant centrosomes do not have centrioles like animals. ** Mitotic Spindle at metaphase: kinetochore microtubules through chromosomes shorten Nonkinetechore Microtubules : overlap, but do not go through chromosomes, and lengthen (motor proteins or “little feet” at overlaps slide and lengthen the spindle.) Astermicrotubules : each centrosome has little microtubules that go in no particular direction, seen on left and right centrosomes. -
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This note was uploaded on 02/01/2011 for the course BISC 1111 taught by Professor Brown during the Fall '10 term at GWU.

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Test 2 Review Packet - BISC11 REVIEW 1 BIOLOGY TEST 2...

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