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A View of the Cell

A View of the Cell. From Molecules to Cells The Evolution of Cells. Life arose in the oceans Molecules collide and reactions take place Larger biomolecules form (nucleic acids, lipids …) Membranes spontaneously form from lipid materials – provides a boundary

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A View of the Cell

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  1. A View of the Cell

  2. From Molecules to CellsThe Evolution of Cells • Life arose in the oceans • Molecules collide and reactions take place • Larger biomolecules form (nucleic acids, lipids …) • Membranes spontaneously form from lipid materials – provides a boundary • Cells begin to replicate; transfer genetic material

  3. Why do we study cells?

  4. The Cell Theory Thecell theoryis made up ofthree main ideas: • All organisms arecomposed of one or more cells • The cell is the basic functional unit of organisms • Schleiden – botanist (1838) - all plants are composed of cells • Schwann – zoologist (1839) - all animals are composed of cells • All cellscome from preexisting cells • Virchow– physician (1855) - all cells come from other cells

  5. Activities of life • Most everything you think of a whole organism needing to do, must be done at the cellular level… • reproduction • growth & development • energy utilization • response to the environment • homeostasis

  6. Diversity of Cells Relationship betweenstructure&function

  7. ALL CELLS… • contain cytoplasm(fluid-filled interior) • are surrounded by aplasma membrane • containDNA (genetic material)in the form of chromosomes/chromatin • haveribosomes(organelles that make proteins)

  8. Two Cell Types • Prokaryotic = no true nucleus • 1st to evolve • Bacterial cells • no membrane bound organelles • Smaller size • Eukaryotic – has a nucleus • contain membrane bound organelles • much larger • classified as either plant or animal cells

  9. PROKARYOTIC CELL - BACTERIA ONLY Ribosomes DNA Plasma Membrane Cytoplasm

  10. EUKARYOTIC CELLS - Plant & Animal Cells Nucleus(containing DNA) plasma membrane ORGANELLES (membrane bound) Ribosomes

  11. What jobs do cells have to do? • transport materials, maintain homeostasis • Take in what is needed; get rid of waste • make proteins • proteins control every cell function • make energy • for daily life; for growth • build more cells • growth • reproduction • repair

  12. Maintaining Homeostasis • Homeostasis = regulation • maintenance of a stable internal environment • Requires bringing in & storage of needed materials • Transporting materials to their intended destination • Elimination of waste materials

  13. What happens if an organelle (like a lysosome) doesn’t work? • don’t digest a biomolecule • instead biomolecule collects in lysosomes • lysosomes fill up with undigested material • lysosomes grow larger & larger • eventually disrupt cell & organ function • Tay-Sachs disease • lipids build up in brain cells • child dies before age 5 Tay-Sachs

  14. Making Proteins: The Endomembrane system

  15. TO: TO: TO: endoplasmicreticulum nucleus proteinon its way! DNA RNA vesicle vesicle ribosome TO: protein finishedprotein Golgi apparatus Making Proteins

  16. Mitochondria&Chloroplasts Making Energy BOTH: • transform energy • double membranes • contain own DNA • self-replicate Dividing mitochondria Dividing Bacteria

  17. Endosymbiotic theory 1981 | ?? • Mitochondria & chloroplasts were once free living bacteria • became engulfed by a larger eukaryote • evolutionary advantage for both • one supplies energy • the other supplies raw materials & protection Lynn Margulis U of M, Amherst

  18. Endosymbiosis Evolution of eukaryotes PLANT CELLS mitochondria chloroplast Early EUKARYOTE Engulfing photosynthetic Prokaryote Engulfing Aerobic Prokaryote Early PROKARYOTE mitochondria ANIMAL CELLS

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