CYTOLOGY

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CYTOLOGY

• Study of cells

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Cell Theory

• Cell basic unit of life

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Cell Theory/Microscopy

• Two men from the 1600s --Hooke
• Leeuwenhoek
• From the 1800s
• Schleiden
• Schwann

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Microscopy Robert Hooke

• English scientist
• Also built a microscope
• He actually invented the term cell because it
  reminded him of the cells in a honeycomb.

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HOOKES VIEW OF WINE CORK SLICED THINLY
CELLS
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Microscopy Leeuwenhoek

• Dutch scientist interested in lens grinding
• Produced wonderful microscopes
• pond water, tooth scum and semen - viewed first
  living cells

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Leeuwenhoek

• Told others of his finds and drew detailed
  drawings
• Microbiology

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Cell Theory Schleiden and Schwann

• German scientists helped to establish the Cell
  Theory
• Schleiden - a botanist - studied plants
• Schwann - a zoologist - studied animals

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Schleiden and Schwann

• In the 1830s they stated jointly that
• ALL LIVING THINGS ARE COMPOSED OF CELLS - both
  plants and animals!

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More Cell Theory

• In the 1850s people accepted the cell theory but
  wondered -
• Where did cells come from in the first place?
• Spontaneous generation was one answer ...

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Spontaneous Generation

• Most troublesome were the bacteria and fungi
  found in nature
• Many people believed these could form
  spontaneously
• Not Pasteur and Virchow

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Louis Pasteur

• French scientist
• Cooked broth very thoroughly and sealed it
• Nothing grew in this broth - Pasteurization was
  invented
• Rivals said lack of Oxygen kept life from
  developing

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Pasteurs Revenge

• Pasteur proved them wrong however with a simple
  experiment

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Virchow

• similar experiments
• same conclusions
• Living cells come from previously existing cells
• There is no spontaneous generation

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Todays Views

• Big Bang Theory
• Oparin, Haldane, Fox, Miller
• Creationism
• Genesis, Chapter 1

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Modern Cell Theory

• All organisms composed of one or more cells
• Cells are smallest living things-basic unit of
  structure and function
• Cells arise only from pre-existing cells

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Cell Types ProkaryoticEukaryoticArchaea-ic
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Types of Cells

• Biologists today recognize two basic types of
  cells
• PROKARYOTIC
• EUKARYOTIC
• Archae-ic (Newly recognized cell type)

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Prokaryotic Cells

• Very simple, primitive
• No internal compartments
• No nucleus
• Very small
• Few organelles
• Bacteria and cyanobacteria

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Eukaryotic Cells

• Complex internal structure
• Compartmentalization of chemistry in organelles
• Nucleus
• Varying sizes
• Typical plant and animal cells

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Theory of Endosymbiosis

• Eukaryotic cell developed when a smaller
  prokaryotic cell began to live inside a larger
  prokaryotic cell
• Scientists evidence
• Mitochondria and Chloroplasts

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Archeae cells

• Newly recognized
• Similar to prokaryotes
• DNA similar to eukaryotes
• Unusual
• Different

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CELL SIZE

• Microscopic generally
• Micrometers in size
• Avg. plant / animal cell is
• 10-30 um others smaller
• Organelles nanometers in size

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Cell Size Restrictions

• Surface to volume ratios
• Nuclear control
• Diffusion Rates

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CALCULATIONS - cube shape

• Ratio Total Surface Area
• Volume
• Surface Area 6 (s x s)
• Volume ( s x s)h

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CELL SHAPE

• Varied
• Imp. to remember 3 - D

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CELL FUNCTIONS

• Performed by organelles
• Allows several functions to occur simultaneously

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Overview of Cell StructureCommon to ALL Cells

• Surrounded by Plasma Membrane
• Genetic Material (DNA) in central region
• Cytoplasm inside plasma membrane