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Cell Structure and Function Cellular Basis of Life, Homeostasis

Cell Structure and Function Cellular Basis of Life, Homeostasis. Chapter 7. Life is Cellular. Early microscopes A series of lenses that could make small things easier to look at (1500) Robert Hooke (1665) – looked at a slice of cork

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Cell Structure and Function Cellular Basis of Life, Homeostasis

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  1. Cell Structure and FunctionCellular Basis of Life, Homeostasis Chapter 7

  2. Life is Cellular • Early microscopes • A series of lenses that could make small things easier to look at (1500) • Robert Hooke (1665) – looked at a slice of cork • Came up with the name “cell” because the empty chambers he saw looked like tiny rooms in a monastery • Anton van Leeuwenhoek (1665) – used a hand lens to look at pond water

  3. Life is Cellular • Cell Theory • All living things are made of cells • Cells are the basic units of structure and function in living things • New cells are produced from existing cells

  4. Light microscopes Light passes through a specimen and two lenses Often uses stains to make specimens more visible Electron Microscopes Beams of electrons are focused by magnetic fields Allows us to see smaller objects that are not viewable by light microscopes Exploring the Cell Microscopes use lenses to magnify the image by focusing light or electrons

  5. Prokaryotes Do NOT enclose DNA in nuclei Generally smaller and simpler Example - bacteria Eukaryotes Enclose DNA in nuclei (large membrane enclosed structure) Contain dozens of structures and internal membranes Example – plants, animals, and fungi Two Major Types of Cells All Cells have: Cell membrane DNA

  6. Cell Structure

  7. Cell Structure

  8. Cell Transport • Movement of materials • Occur at boundaries ( membranes) • Two Major Types • Passive • Active

  9. Structure of the Cell Membrane • Double layer (called lipid bilayer) • Provides flexibility • Lipids in membrane have two parts • Hydrophilic (water-loving) heads • Hydrophobic (water-fearing) tails

  10. Passive Transport • Movement without the use of cellular energy • Diffusion – particles move from high concentration to low concentration (any type of material) • Equilibrium – equal concentration on both sides of the membrane • Facilitated diffusion - large molecules need help to travel across the membrane • Uses protein channels • Osmosis – diffusion of water • Isotonic – same • Hyper – more • Hypo - less

  11. Active Transport • Movement against a concentration gradient • Requires energy • Carried out by protein pumps • Two processes that transport larger molecules • Endocytosis – entering the cell • Exocytosis – exiting the cell

  12. Homeostasis and Cells • Relatively constant internal physical and chemical conditions • Unicellular organism • Grow • Respond to the environment • Transform energy • Reproduce • Multicellular organism • Cell specialization • Levels of organization • Cellular communication

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