1 / 70

The Tour of the Cell

The Tour of the Cell. Chapter 6. The Fundamental Units of Life. All living things composed of cells Cell structure correlated to cell function All cells descend from existing cells. Microscopy. Light microscope = visible light through specimen magnified by lenses Up to 1000X.

dakota
Télécharger la présentation

The Tour of the Cell

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Tour of the Cell Chapter 6

  2. The Fundamental Units of Life • All living things composed of cells • Cell structure correlated to cell function • All cells descend from existing cells

  3. Microscopy • Light microscope = visible light through specimen magnified by lenses • Up to 1000X

  4. Electron microscopes (EMs) • Scanning EM (SEM) focus beam of electrons onto surface  3-D image • Transmission EM (TEM) • focus beam of electrons through specimen •  internal structures

  5. Gills of fish yeast • HIV

  6. Cell Fractionation centrifuge separates cell components

  7. TECHNIQUE Homogenization Tissue cells Homogenate Differential centrifugation

  8. TECHNIQUE (cont.) 1000 g 10 min Homogenate Pellet Supernatant Supernatant poured into next tube 20,000g 20 min 80,000g 60 min 150,000g 3 hr Nuclei, debris  mitochondria  membranes  ribosomes

  9. Prokaryoticcells= Archaea and Bacteria • No nucleus, no membrane-bounded organelles • DNA in nucleoidregion 0.5 µm

  10. Eukaryotic cells = Plants, Animals, Fungi, Protista • DNA in nucleus • Organelles • Membrane bounded • Cytoplasm = fluid + organelles • Cytosol = fluid

  11. Featured scientist: Robert Hooke 1635-1703

  12. Micrographia was a best seller Best CLM of its time!

  13. The famous slide: . . . I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular. . . . these pores, or cells, . . . were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this. . .

  14. Features of cells 1. The plasma membrane = selective barrier allows passage of oxygen, nutrients, waste etc • Composed of phospholipid bilayer

  15. 2. Surface to Volume ratio high • Small cells have greater surface area relative to volume • Larger organisms do not have larger cells than smaller organisms Human Rat

  16. The Eukaryotic Cell

  17. 1. The Nucleus Hela cells

  18. A. Nuclear envelope (NE) • Double membrane; each a bilayer • Poresregulate entry and exit of molecules from nucleus

  19. Nuclear lamina fibrous proteins maintain shape of nucleus Lamin A and lamin B can bind histones – may have role in chromosome organization

  20. B. Chromatin= DNA + proteins • Chromosomes = strands of chromatin

  21. C. Nucleolus • Assembles ribosomes

  22. D. Nucleoplasm • Viscous fluid of nucleus

  23. 2. Ribosomes: Protein Factories • Assemble amino acids into polypeptides • cytosol (free ribosomes) • RER/NE (bound ribosomes)

  24. 3. The Endomembrane System • Components • Nuclear envelope • Endoplasmic reticulum (ER) • Golgi apparatus • Lysosomes • Vacuoles • *Plasma membrane

  25. A. The Endoplasmic Reticulum • >half of total membrane • continuous with nuclear envelope • Smooth ER • lacks ribosomes • Synthesizes lipids • Metabolizes carbohydrates • Detoxifies poison • Stores calcium

  26. Rough ER (RER) • Ribosomes assemble proteins thread through ER lumen  transport vesicles • Membrane factory

  27. B. The Golgi Apparatus • flattened membranous sacs called cisternae • cis and trans face trans face (“shipping” side of Golgi apparatus)

  28. Functions of the Golgi apparatus: • Modifies proteins from ER • Sorts and packages protein into transportvesicles Golgi makes polysaccharides in plants

  29. Nucleus Rough ER SmoothER cisGolgi • Where do the vesicles go? Plasma membrane trans Golgi

  30. Virtual cell Note: Ribosome, RER, vesicle, Golgi

  31. C. Lysosomes • membranous sac of enzymes that digest macromolecules • What do they do? recycle cell components (autophagy) get rid of phagocytosed invaders form food vacuoles How do they work?

  32. phagocytosis A cell engulfs another cell to form a food vacuole • lysosome fuses with food vacuole and digests molecules

  33. D. Vacuoles • Food vacuoles formed by phagocytosis • Contractile vacuoles • freshwater protists • store or/and pump excess water out of cells

  34. Central vacuoles • found in many plant cells • hold organic compounds and water

  35. 4. Mitochondria Outer membrane • cellular respiration generates ATP (energy) • contain mtDNA • all eukaryotic cells have mt • Some have 1, some 1000s Cristae

  36. mitochondrion

  37. Mitochondria • outer membrane and inner membrane fold into cristae • large surface area for enzymes that synthesize ATP

  38. 5. Chloroplasts (plastid) • found in plants and algae • sites of photosynthesis • green pigment chlorophyll, enzymes, other molecules

  39. 6. Peroxisomes • detoxify catalase 2 H2O2 2H2O + O2 (toxic)

  40. Bioflix Tour of animal cell – the big picture • Note: • Sticky extracellular matrix • Plasma membrane • Cytoskeleton • Mitochondria- ATP, surface area • Nucleus and nuclear envelope with pores • DNA and protein wrappings, code for protein • Ribosome builds protein • Endomembrane system = RER and SER + Golgi

  41. 7. Cytoskeleton • Network of protein fibers organize structures and activities in cell • Anchors organelles • Maintains cell shape

  42. Cytoskeleton • interacts with motor proteins to transport cargo or for movement

  43. 10 µm Column of tubulin dimers 25 nm Tubulin dimer  

More Related