Biology 1 - Mod 3 Cell Discovery

Discovery of the Cell

1590: Zacharias Janssen

  • First compound microscope

1665: Robert Hooke

  • Looked at cork under the microscope
  • Called the empty chambers he saw ‘cells’

1674: Matthias Schleidon

  • All plants are made from cells

1839: Theodor Schwann

  • All living things are made of cells

1855: Rudolf Virchow

  • New cells only come from existing cells

Cell Theory

  • All living things are made of 1 or more cells
  • Cells are the smallest units of function and structure in life
  • New cells are produced from existing cells

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All cells have 4 things in common:

  • Cell membrane
  • DNA
  • Cytoplasm
  • Ribosomes

Types of Cells

Prokaryotes

  • Do NOT contain a membrane-bound nucleus/organelles
  • Have genetic information, but it isn’t stored in the nucleus.
  • Have the 4 things in common
    • Unicellular

Example: Bacteria (only remaining prokaryote)

Eukaryotes

  • Have a nucleus (contains the DNA)
  • Have organelles (little organs)
    • Unicellular or Multicellular

Examples: Plants, animals, fungi, and protists

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Cell Specialization

  • a cell’s shape (structure) relates to what it does

Example: White blood cells change shape (fit through tight spaces and engulf invaders)

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Cell Organization

Cell → Tissues → Organ → Organ System → Organism

Example: Muscle cell → smooth muscle → tissue → stomach organ → digestive system

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Cell Membrane

Cell membrane diagram

Cell Membrane Structure

Phospholipid bilayer

Glycerol head and 2 fatty acid tails

2 layers

Cholesterol - Prevents fatty acid tails from sticking together, maintains flexibility

Carbohydrates - identify chemical signals

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