Student_Outline_Unit_2_Starr

Student_Outline_Unit_2_Starr - UNIT 2 GENETICS How cells...

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UNIT 2 GENETICS How cells Reproduce I. Reproduction A. Asexual reproduction – one parent cell/or multicellular organism that gives rise to an offspring and offspring are identical to parent and to each other 1. Who uses it? a. prokaryotes b.single celled eukaryotes( yeast, various protists, amoeba, paramecium) c. some multicellular organisms-some sexual process must take place, starfish, plant cutting) d. somatic cells(body cells) all cells that are not sex cells:gametes 2. Consequence-all offspring are genetically identical B. Sexual reproduction – includes two parents and offspring are not identical to either parent II. Eukaryotic Cell Cycle-(2 phases) A. Interphase –3 subphases: 1. G1 (Gap 1)interval of cell growth before DNA replication (chromosomes unduplicated) 90% of time in this phase, Gap before DNA synthesis a. increase in supply of organelles b. general growth(size of parent cell increases) 2 . S ( Synthesis ): interval of cell growth when DNA replication is completed Chromosomes duplicated) DNA synthesis a. chromosomes replicateand remains joined to its sister chromatid, once joined call them chromatids b. growth of cell 3. G2 (Gap 2) after DNA synthinterval following DNA rep. cell prepares to divide a. protein synthesis( ex. A lot of tubule produced) b. general metabolic activity(ATP production) 1
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B. Mitosis (M)- 4 subphases: 2 daughter cells identical to parent cell 1. Prophase a. DNA –condense(coil more) becomes visible in light microscope b. Nuclear envelope and nucleolus-break up and begin to disappear c. Spindle –(made up of microtubules) begins to form One end of spindle joined to:Kinetochore at the centromere Kinteochore:complex of proteins at centromere Other end of spindle joined to:pole of the cell d. Sister chromatids (replicated chromosomes) move – towards the equator of the cell 2. Metaphase: “midway” a. Sister chromatids –at the equator(metaphase plate) b. Spindle – completed(joined to each chromatid and pole) Some spindle fibers at the equator are not attached to chromatids, what are they attached to? Other fibers from the opposite pole c. Nuclear envelope -gone 3. Anaphase a. Sister chromatids – separate from each other b.Spindles shorten – (attached to each chromatid) c. Spindles lengthen –( attached to opposite spindles cell elongates but chromosomes more to poles 2
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4. Telophase/Cytokinesis – begins once all chromosomes at spindle poles a. DNA –uncoil again b. Nuclear envelopes and nucleoli- reappear (2) (2) c.Spindle – disassemble d. Cytokinesis: cytoplasem divides 1. animals – “cleavage”-microfilaments form a ring and they “pinch” the cell 2. plants – cell plate formation:fusion of cellulose-containing vesicles PRACTICE: To the left is a picture of the chromosomes of a cell in G1 of the cell cycle. Draw what this cell will look like at: 1) G2 2) Metaphase 3) After cytokinesis Checkpoints(G,S G2) during mytosis, if they don’t occur a person gets cancer Chemotherapy kills cells going through mitosis, won’t kill majority because some are in interpahse but hair
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Student_Outline_Unit_2_Starr - UNIT 2 GENETICS How cells...

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