Week 1

Levels of structural organization:

Chemical level- atoms

Cellular level,

Tissue level- 4 classes of tissue, all found in organs

Organ level

Organ system level

Organismal level

3 historical strands of science, biochem, genetics, histology (cytology). All melded into cell biology, formed in 1930’s?

cell theory: 1839 Schwann postulated the cell theory

All organisms consisting of one or more cells, the cell is the basic u it if structure for all organisms

Virchow, 1855, all cells Arise efforts pre-existing cells.

Robert Hooke, 1665, looked at cork through microscope and determined cells. Called the “chambers” cellulae

Cytology: the study of cell using a microscope.

Light microscope, Lagro, earliest tool of cytologists. Allowed to see inside of cells

Electron microscope, uses a beam of electrons through a specimen or bounces off specimen. More detailed. Can magnify 100,000X+ and resolution 0.1-0.2 nm. Can see much smaller things than light microscope

Magnification: the process of enlarging the apparent size of an object t

Resolving power: the distance by which two is objects ,use be separate to appear as two. The resolving power of an unaided eye is 2mm

Hooke’s microscope only had one lens and made it 30X, resolution is 83 micrometers

Modern light microscope is up to 1400X with 200 nm

Different types of light micros: brightfield (lagro) is most common, phase contrast, differential interference, fluorescence, confocal (laser)

Micrograph: picture taken with microscope

Treponema bacteria is syphilis

Types of Electron micro: TEM, transmission electron micro, electrons through a specimen., SEM, scanning electron microscope

Biochem: Wöhler (1828) showed urea made in a living organism could be made

Pasteur: alcohol =enzymes

Embden and Meyerhof described steps of glycolysis 1930

Hans Krebs described Krebs cycle. TCA cycle after. Both are important for energy metabolism.

Chromatography: separate molecules based on size, charge, or chemical affinity

Mendel’s experiment with peas in 1866 laid the foundation for understanding the passage of hereditary factors, known as genes.

Flemming 1880, saw threadlike bodies in the nucleus called chromosomes

Roux 1883, & Weisman suggested the Chromosome carry genetic info.

Morgan, bridges, and sturtevant 1920’s used fruit flies to identify traits

Miescher 1869, first isolated DNA. 1914 known as components. 1930’ all components identified

1953 Franklin, Watson, crick DOUBLE HELIX

electrophoresis, separating DNA and RNA in gel

Recombinant DNA technology uses enzymes to cut DNA at specific locations to recreate healthier DNA

Scientific method: observe, question observations, form hypothesis, collect data, recollect data, conclusion

Levels of scientific certainty:

Hypothesis: a statement consistent with the most data

Theory: a hypothesis that has been extensively tests by many investigators

Law: a theory that has been tested over long periods and there are no doubt of validity

Occam’s Razor: when faced with two possible explanations, the simpler of the two is most likely to be true

Occam’s professor: she faced with two possible ways of doing something, the more complicated one is the one your professor will most likely ask you to do

Basic Chemistry:

Atom smallest unit, protons, neutrons, electrons

Elemental state: neutral atom- oxidation number(state)=0

Oxidation-reduction reactions change the state of the atom by adding or getting rid of electrons

Atomic number: number or protons

Atomic weight: 6.23X10²³

Atoms with full outer shells are very stable (unreactive)

Atoms with infilled outer shells arr less stable (reactive)

Inner-most shell can hold 2 electrons, outer shells can hold 8.

Unpaired electrons= valence electrons- valence number, will determine how an atom with react with another

Paired electrons don’t play a role in bonding

Ionic bonds: one atom donates an outer shell electron to another

Covalent bonds: atoms share an electron in outer shells