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The Cell

The Cell. Cell Theory/History Structures Transport Differentiation Levels of Organization. Robert Hooke. English physicist 1665 Saw a slice of cork tree tissue Tiny chambers Termed them “cells” (looked like monks’ cells in monastery). Robert Hooke. Published his book Micrographia

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The Cell

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  1. The Cell Cell Theory/HistoryStructuresTransport Differentiation Levels of Organization

  2. Robert Hooke • English physicist • 1665 • Saw a slice of cork tree tissue • Tiny chambers • Termed them “cells” (looked like monks’ cells in monastery)

  3. Robert Hooke • Published his book Micrographia • Contained drawings of cork cells • Used early microscope

  4. Anton Van Leeuwenhoek • Dutch businessman • 1674 • Perfected microscope (about 300x) • Saw living things in pond water • “Animalcules” • Observed bacteria (on wood teeth) and protozoa

  5. Matthias Schleiden • German botanist • 1838 • Concludes that all plants are made up of cells

  6. Theodor Schwann • German zoologist • 1839 • Concluded that all animals are made up of cells

  7. Rudolph Virchow • German physician/pathologist • 1855 • Worked with eggs from various organisms • Proposes that all cells come from existing cells

  8. Cell Theory • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.

  9. Janet Plowe • 1931 • Demonstrates that the cell membrane is a physical structure, not an interface between two liquids.

  10. Lynn Margulis • 1970 • Proposes a theory that certain organelles were once free-living cells themselves

  11. Singer - Nicholson • 1972 • Fluid Mosaic Model • Membranes are phospholipid bilayers with globular proteins embedded in them • Membrane is always moving • Made up of smaller pieces (mosaic)

  12. Prokaryote cells • Very simple (bacteria)

  13. Eukarote cells • Larger, complex

  14. Cell Structures

  15. Barriers… • Cell Wall • Plants & prok. (not animals) • Structural (plant support) & protective role • Cellulose • Freely permeable

  16. Cell walls of onion skin…

  17. Barriers… • Cell Membrane (plasma membrane) • In ALL cells • Support/protection • Regulates movement in/out of: • Water • Nutrients • Waste products

  18. Cell Membrane...

  19. Barriers… • Nuclear Envelope (nuclear membrane) • Surrounds nucleus • Thousands of pores • Material move in/out, incl. RNA

  20. Nuclear envelope

  21. Fluids… • Cytoplasm (cytosol) • Bet. cell mem. and nuclear env., site of most chemical activity • Nucleoplasm • Semi-fluid medium of nucleus • Protoplasm • Term used for all substances inside cell

  22. The Nucleus The Control Center

  23. The Nucleus… • Controls most cell processes • Contains Chromatin • DNA bound to proteins • During cell division, condenses to Chromosomes… • Has a Nucleolus • Small, dense region • Assembly of Ribosomes • Nuclear Envelope (or membrane)

  24. Organelles of the cytoplasm Little Organsassist the cell in conducting reproductive, respiratory, and structural needs

  25. Cytoskeleton… • Protein filaments • Maintains cell shape • Involved in cell movement

  26. Cytoskeleton

  27. Ribosomes… • Small,made of RNA • Assembly of proteins • Free in cytoplasm or att. to ER

  28. Endoplasmic Reticulum… • Called “ER” • Two types: • Rough ER • Ribosomes stud surface • Aids in synthesis and modif. of proteins • Found wrapped around nucleus • Smooth ER • No ribosomes • Special tasks with certain enzymes (such as making lipids)

  29. Mitochondrion… • Uses energy from food • Makes high-energy compounds (ATP) needed for Rx elsewhere. • The POWERHOUSE of the cell

  30. Golgi Apparatus… • Receives proteins from rough ER • Enzymes attach carbs and lipids to the proteins • Can store proteins until needed • Proteins then sent to final destination • PACKAGING and SHIPPING

  31. Golgi Apparatus

  32. Vacuoles… • Saclike structure • Stores water, salts, proteins, carbs • Can be large in plant cells • Helps in plant support by keeping turgor pressure high

  33. Vacuoles

  34. Vacuoles Korotnovella, an amoeba. Inside this cell we can see a nucleus near the center with a rather angular dark nucleolus, various food vacuoles, and a clear round contractile vacuole at about 10 o'clock.

  35. Lysosomes… • Filled with enzymes • Breaks down • lipids, carbs, and proteins from food • old organelles • debris and harmful invaders

  36. Video

  37. Plastid 1: Chloroplasts… • In plants, not animals or fungi • Uses sunlight to make energy rich food mol. thru photosynthesis

  38. Chloroplasts…

  39. Chloroplast

  40. Plastid 2: Leucoplast • Sometimes called amyloplast; stores starch (amylose = starch)

  41. Plastid 3: Chromoplast • Stores pigments in plants

  42. Centrioles • Cylindrical; group of microtubules • In animal cells, used in cell division • As “basal bodies,” form cilia and flagella

  43. The Cell Membrane • Is composed of a phospholipid bilayer • A barrier; reg. what passes in/out • Supports and protects • Selectively permeable – only certain things pass through. • About 5 nanometers thick (1 nm = 1 Billionth of a meter)

  44. Cell membrane - Structure • A phospholipid contains- • one head; negatively charged phosphate group that is hydrophilic (water-loving) • two tails of fatty acid chains that are hydrophobic (water fearing)

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