STUDY GUIDE-CHAPTER 9 BIO II

STUDY GUIDE-CHAPTER 9 BIO II - CHAPTER 9 STUDY...

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CHAPTER 9 STUDY GUIDE— CHROMOSOMES, CELL, CELL DIVISION CELL DIVISION -Three types: Binary Fission o Prokaryotes Bacteria (Principle way they reproduce) True Archae o Reproduction o Daughter Cells are genetically identical to each other and parents Two from one parental cells Mitosis o Eukaryotes o Primarily Growth/Repair in multicellular species o Production of gametes in some (not humans) o Unicellular Eukaryotes—just like Binary Fission but mitosis o Daughter Cells are genetically identical Meiosis o Eukaryotes o Typically used in production of gametes (humans) o Daughter cells NOT genetically identical -Four events required for Cell Division 1. Reproduction signals initiate. o Inside cell (unicellular); Outside cells (multicellular); cancer cells=no signal 2. Replication of DNA o Depending on cell division leads to segregation
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3. Segregation of replication DNA to daughter cells 4. Cytokinesis—seperation of parent cell into two daughter cells. BINARY FISSION -Clone daughter cells Events: o 1. Single circular chromosome is much folded producing a nucleoid region. Some have linear chromosome o 2. Replication of chromosome begins at single point of origin of replication (ori) and terminates at the terminus (ter) o 3. The cell increases length by growth (add material that has function— segregation) o 4. The daughter chromosomes separates from each other (motor proteins/cytoskeleton have roles) as the cells: o 5. Septation—A septum forms that separates daughter cells; pinches off each other [Fig 9.2] Occurs as result of formation of protein FtsZ (also in cytokinesis) Forms rings at midpoint-signals materials to form septum. FtsZ similar to tubulin (in eukaryotes cell division)—component of microtubules (used in mitotic/meiotic spindles) o RELATIONSHIP UNCLEAR CELL DIVISION IN EUKARYOTES ARE MORE COMPLEX -Presence of more DNA -More than one chromosome (At least one pair or two chromosomes) -And Nuclear envelope—surrounds nucleus *Sequence leading from binary fission to mitosis is unclear* *Sequence leading from FtsZ to tubulin is unclear* -Details of mitosis differ among different eukaryotes Protista o Nuclear envelope remains intact
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o Spindles develop in nucleus o Chromosomes attach to inner surface of nuclear envelope. Most plants/animals o The nuclear envelope fragments o Spindle develops outside nucleus o Chromosomes don’t attach to envelope. EUKARYOTIC CHROMOSOMES -Walter Fleming mitosis Restriction to segregation of daughter sets of chromosomes, not cytokinesis Number of chromosomes differ among Eukaryotes (2 to 1000) o Homo Sapiens 23 pairs/46 chromosomes [Table 9.1] -Each chromosome has many genes, often thousands Many eukaryotes don’t tolerate having an abnormal number of chromosomes— especially the somatic chromosomes One too many (three)—Trisomy (Down Syndrome—3 on 21 st chromosome) One too few (one)—monosomy -Eukaryotic chromosomes made of chromatin—complex of DNA/proteins
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This note was uploaded on 02/03/2011 for the course BIOSC 160 taught by Professor Coffman during the Spring '10 term at Pittsburgh.

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STUDY GUIDE-CHAPTER 9 BIO II - CHAPTER 9 STUDY...

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