CELL BIOLOGY HISTORY

23 Sept 91, rvsd 26 Sept 1994, 20 Sept '95, 25 Sept '96, 24 Sept 01, 24 Sept 02, 24 Sept 03, 21Sept05, 19Sept07

B&D p 2-12 , [BKL, 6^th: 2-11?], BKH 5^th, 1-13, BKH 6^th, 1-13

Dynamic nature of cell:              1. grow

                                                    2. reproduce

                                                    3. become specialized

                                                    4. respond to stimuli

                                                    5. adapt to environment

Cell biology formed by convergence of :             1. cytology

                                                                              2. genetics

                                                                              3. biochemistry.

HISTORY OF CYTOLOGY: (see p 4)

First descriptive then investigative, often dependant on new technology.

DESCRIPTIVE

Robert Hooke,              1665, Curator of Instruments for Royal Society, viewed thin slices of cork under 30x lens, showed network of tiny compartments, he called cellulae (little rooms)

Antonie van Leeuwenhoek  1673 cloth merchant, developed simple 300x microscopes, examined everything, illustrated, communicated to Royal Society last quarter of 17th C.

INVESTIGATIVE:

Robert Brown              1833, English botanist, using improved lenses, noted that every orchid epidermis cell had round structure he termed nucleus

Matthias Schleiden      1838, German botanist, concluded all plant tissues composed of cells, and embryonic plant arose from a single cell.

Theodor Schwann        1839, German zoologist, examined cartilage tissue (better cellular definition in cartilage), concluded all animal tissues are composed of cells

                                       He proposed first two tenets of cell theory, became:

UNIFIED CELL THEORY (three tenets):

                                               1) all organisms made of cells

                                               2) cell is the basic unit of structure                        [end day one, 2003, 2007]

Karl Nageli                   observed cell division [Remak noted in 1852 division initiated in nucleus.]

Koelliker                       1852, identified four somatic tissue types

Rudolf Virchow            1855, Ger Physiol, concluded cells arose only by division of preexisting cells:

                                       Omnis cellula e cellula, adding 3rd tenet of cell theory:

                                               3) cells arise only from preexisting cells.

TECHNOLOGICAL DEVELOPMENTS OF CYTOLOGY: (cytos = Gk, hollow vessel)

             concerned with cell structure, depended initially on light microscope

microtome                    invented in 1870, allowed analysis of tissue structure

dyes                               developed in Germany 2nd half 19th C, specifically stain particular components

optics improvements pushed to limit:

lambda/2 theoretical limit, thus 400-700 nm lambda, 200-350 nm resolution.

[review micron (10-6) and nanometer (10-9). Cells often 20-40 microns, organelles, 0.2-2 microns.] mag = 1000-1500x

Electron microscope    invented in Ger, 1932.

              Palade, Sjostrand and Porter   used in early 1950s. limit of resol for electron 0.1-0.2 nm Magnification up to 100,000x.

Scanning tunneling microscope able to resolve gen shape of DNA [END, DAY ONE...(not)]

BIOCHEMISTRY and GENETICS:

rvsd 27 Sept '96, 24 sept 99, 24 Sept 01, 27 Sept 02, 24 Sept 03, 21Sept07

BKH, 6^th, p 4, 5 

Friedrich Wohler         1828      vitalism:        believed different laws for living vs non-living (anima), processes occurring in organisms qualitatively different

                                                      Mechanism:   believed same laws applied to all matter, living and not.

Showed urea, an organic molecule, could be formed from ammonium cyanate (NH₃OCN), an inorganic salt. Thus, laws of chem and phys apply to biology, vitalism incorrect.

Louis Pasteur               1880s                showed that yeast conducted fermentation of sugar to alcohol.

Eduard Buchner          1897                  prepared yeast extracts (ferments) and conducted fermentation in vitro. Agents in extracts causing fermentation called enzymes.

                                                                 Again, vitalism wrong, fermentation could occur outside living cells.

Embden, Meyerhof, Warburg, Krebs       Elucidation of biochemical glycolytic pathways by Germans: during 1920s & 30s. (Glycolysis = Embden-Meyerhof pathway) ATP recognized as energy storage molecule.

Melvin Calvin,              1940s-50s         Pioneered use of radiotracer technology

Svedberg, The              1925-30           Ultracentrifuge, in Sweden allowed cellular fractionation

GENETICS:

Gregor Mendel             1866                  studied peas, proposed

                                                                      1. Paired hereditary factors which, during gametogenesis

                                                                      2. segregate and

                                                                      3. assort independently

                                                                 Ignored for 35 years

Friedrich Miescher      1869                  isolated DNA from salmon sperm and human pus. (75 yrs ahead of time)

Walther Flemming      1870s                observed thread-like structures in dividing cells, termed chromosomes, process mitosis.

Wilhelm Roux              1883                  suggested that chromosomes might carry genetic information

Correns, von Tschermak, & de Vries  simultaneously rediscovered Mendel's work.

Walter Sutton               1903                  proposed chromosome theory of heredity, linking Flemming's threads with Mendel's factors.

Thomas Hunt Morgan              1910-1920                      used Drosophila to show Sutton correct.

Robert Feulgen            1914                  developed stain for DNA, showed component in chromosomes, most thought could not be genetic material: composed of only four bases.

Avery, MacLeod and McCarty             1944, showed DNA could transform bacteria

Hershey and Chase      1952                  phage inject DNA, not protein.

James Watson and Francis Crick         1953 elucidated the structure of DNA.

wordstems, first lecture, 1995:

etymo-

logy

cyto

-tome

micro

scope

nux

nucleus

bio-