BOLOGY 107 1st Edition Lecture 18 Outline of Last Lecture I Anaerobic Respiration and Fermentation a Process b Lactic acid fermentation c Alcohol fermentation II Cell division a Mitosis meiosis and cytokinesis b Cell cycle c Mitosis i Chromosomes Outline of Current Lecture III Chromosomes IV Mitosis a Structures formed b Stages c Alternatives Current Lecture Chromosomes 1 When forming sister chromatid copies they become visible as separate a During the S phase 2 Structures a Centromere i Constructed where the sister chromatid attach b Kinetochore i proteins around the centomere where microtubules will attach Mitosis 3 Structures formed a Mitotic spindle i Assemble at centromeres formed of microtubules and associated proteins 1 Asters connect the centromeres to the cell membrane 2 Kinetochore microtubules connect to the kinetochores of the chromosomes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 3 Overlapping microtubules connect to each other in middle of cell 4 Stages a Interphase preparation i Nuclear envelope is present around chromosomes ii Chromosomes are not distinct one ball iii G2 1 Chromosomes are duplicated 2 Centrosomes are duplicated b Prophase i Chromosomes become distinct as they condense ii Centrosomes move to opposite ends of the cell iii Spindle forms c Prometaphase i Nuclear envelope breaks ii Spindle is complete d Metaphase i Centrosomes are at opposite ends of the cell ii Chromosomes align at metaphase plate equidistant from each centrosome iii Cell does not continue until chromosomes are aligned called the M phase checkpoint e Anaphase i Anaphase A 1 Proteins holding chromatids together disintegrate 2 One of each set of sister chromatids move towards a centromere by depolarizing the microtubule and cutting it 3 Now considered daughter chromosomes ii Anaphase B 1 Spindle poles move apart cell elongates f Telophase i Chromosomes arrive at the poles ii Nuclear envelopes form around each bunch of chromosomes iii Chromosomes de condense iv Cytokinesis occurs g Interphase occurs with new cells h Plants are constricted by cell walls and have no centrioles 5 Alternatives to mitosis mitochondria and plastids a Prokaryotes go through binary fission b Protists and some yeasts i Dinoflagellates have no spindle and the nuclear envelope does not breakdown ii Diatoms and some yeasts form the spindle in the nuclear envelope
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