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Monday, Jan. 6

Monday, Jan. 6. Standard 6 Notes/discuss 10.1 Surface area lab. Seating Chart (change =referral). Cell Growth. When living things grow, what happens to it’s cells? Does an organism get larger because each cell increases in size or because it produces more of them????  Stem Cell.

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Monday, Jan. 6

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  1. Monday, Jan. 6 Standard 6 Notes/discuss 10.1 Surface area lab

  2. Seating Chart (change=referral)

  3. Cell Growth • When living things grow, what happens to it’s cells? • Does an organism get larger because each cell increases in size or because it produces more of them????  Stem Cell

  4. Limits to Cell Size • Most cells divide after growing to a certain point • Why??? • Information “overload” • Larger cell would make greater demands on genetic “library” (DNA) • DNA would no longer be able to serve the needs of the growing cell- build a new “library” • Exchanging materials • A decrease in the relative amount of cell membrane available (surface area) creates serious problems

  5. Surface area to volume ratio in cells Not enough substances getting in cell Not enough waste getting out of cell Heat build up in cell

  6. Cell division • The process by which a cell divides into two new daughter cells • Cell replicates all of its DNA first • Reduces cell volume, increases ratio of SA to V= efficient exchange of materials

  7. Cell reproduction • Asexual • Genetically identical • From a single parent • Simple, efficient, effective • Sexual • Inherit some genetic info from TWO parents • Creates genetic diversity

  8. Comparison Sexual Asexual Requires more time- find mate, growth ad development Can be advantage due to seasonal changes, food availability Genetic diversity- equipped for change in environment Survival strategy for single-celled organisms Faster they reproduce the better their chance of survival Lack of genetic diversity is a disadvantage- not equipped for change in environment

  9. Tuesday, Jan. 7 Reading quiz 10.1 Notes/discuss 10.2 Onion root tip lab HW: Mitosis worksheet

  10. Chromosomes • What if a cell were simply split in two?? • DNA needs to be replicated first; cell can’t function with ½ of it’s DNA • Genetic info is bundled into packages of DNA known as chromosomes. Chromatin= DNA+protein, uncoiled chromosomes Chromosome= supercoiled chromatin

  11. Compare Prokaryotic Chromo Eukaryotic Chromo Single chromo Circular In cytoplasm- no nucleus Multiple chromos Histones- protein that DNA coils around Make it possible to separate DNA precisely during cell division

  12. The Cell Cycle Cells grow, prepare for division, and divide to form two daughter cells

  13. Compare Prokaryotic cell cycle Eukaryotic cell cycle Binary fission- single-celled produces two genetically identical organisms Four phases: G1, S, G2, and M.

  14. Eukaryotic Cell Cycle • G1phase: cell growth • Increase in size, synthesize new proteins and organelles • “G” stands for “gap” • S phase: DNA replication • “S” stands for “synthesis” • New DNA is synthesized when DNA replicates • At end of S phase, cell has double the DNA • G2 phase: preparation for mitosis • Shortest phase • Organelles and molecules needed for cell division are produced • M phase: Cell division • Produces two daughter cells • Involves two processes: mitosis and cytokinesis • M for “mitosis” • Takes place quickly Interphase

  15. Mitosis (P-MAT) • Prophase • Genetic material condenses, becomes visible • Spindle fibers form outside nucleus • Nucleolus disappears and nuclear membrane breaks down • Metaphase • Centromeres line up in center of nucleus • Spindle fibers connect to centromere • Anaphase • Chromosomes separate and move along spindle fibers to opposite ends of cell (poles) • Telophase • The chromos go back to being spread out (chromatin) • Nuclear membrane and nucleolus re-form in each daughter cell

  16. Cytokinesis • Ends M phase • Division of the cytoplasm • Occurs at same point in time as telophase • In plants: • Cell plate develops between two nuclei • Cell plate gradually becomes cell membrane, the cell wall formed • In animals: • Cell membrane drawn inward “pinches” into two equal parts

  17. Wednesday, Jan. 8 Collect mitosis HW Introduce stop-action film

  18. iPhoto (on launch pad) Take 10 separate images of an object, moving it an inch farther for each new photo

  19. Thursday, Jan. 9 Create storyboard (use rubric)

  20. Friday, Jan. 10 Finish storyboard Begin creating “scenes”

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