BIOL130 Lecture Notes - Scanning Electron Microscope, Antonie Van Leeuwenhoek, Great Salt Lake

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Unit 1: Introduction to the Cell
KEY TERMS
historical
o light microscopy and the discovery of the cell
o cell theory
o facts, hypotheses, theories and the scientific method
o ‘strands’ of cell biology – cytology, biochemistry, genetics
basic properties shared by all cells
classes of cells
o prokaryotes - two kingdoms
o eukaryotes- membrane-bound compartments, nucleus
endomembrane system ER, Golgi, lysosomes, vesicles
mitochondria, chloroplasts
o origins of eukaryotic cells - endosymbiont theory
cytoskeleton
model organisms in cell biology
Greek/ Latin roots of Cell Biology
CELL THEORY HISTORY
Before microscope, it was not known that cells exsisted
Robert Hooke (1635-1703)
o first microscope
o viewed slices of cork
o found “cellula” (little rooms- actually saw cell walls)
Antoni Van Leeuwenhoek (1632-1723)
o “father of microbiology”
o worked with glass huge improvement in quality of lenses nearly 300x magnification became
possible
o first to observe: (drew what he saw)
single-celled organisms “animalcules
protists from pond water
bacteria from his mouth
blood cells
banded pattern in muscle cells
sperm
Progress stalled for a century
o limited resolving power
o emphasis on description rather than explanation
(only drawings)
Compound microscope (1830s)
o improved magnification and resolution
o allowed visualization of objects less than 1 μm
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Beginnings of Cell Theory
1833 Robert Brown (botanist)
o noticed that every plant cell contained a round structure “kernel” (now known as nucleus)
1838 Matthias Schleiden (another botanist)
o all plant tissues are composed of cells
o embryonic plant always arose from a single cell
1839 Theodor Schwann (zoologist)
o similar observations in animal cells
o recognition of structural similarities btw plants and animals!
o Cell Theory was formulated (challenged religious and cultural views)
CELL THEORY
all organisms consist of one or more cells
the cell is the basic unit of structure for all organisms
all cells arise only from pre-existing cells (added 20 years later)
FACTS AND SCIENTIFIC METHOD
fact:
o something we know and believe to be true …
fact (scientific):
o an attempt to state our best current understanding (based on observations and experiments)
o valid only until revised or replaced by a better understanding, based on more careful observations or
more discriminating experiments (can be revised)- a fact it only a fact until it is proven to be not true
theory:
o a hypothesis that has been tested critically under many different conditions and by many different
investigators using a variety of different approaches
o by the time an explanation is regarded as a theory it is widely accepted by most scientists in the cell
o the “solid ground” of science
o evolution, germ theory, cell theory
law:
o if a theory is thoroughly tested and confirmed over many years, it becomes a law
o gravity, laws of thermodynamics, laws that govern behaviour of gases
o biologists are conservative about using the term ‘law’ (revise theories instead)- mainly used in physics
Scientific Method:
o make observations
o use inductive reasoning to develop tentative explanation (hypothesis)
o make predictions based on your hypothesis
o make further observations or design and carry out controlled experiments to test your hypothesis
o interpret your results to see if they support your hypothesis
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STRANDS OF CELL BIOLOGY
Biochemistry (synthesis in a lab)
Cytology (looking at cell directly)
o Light Microscopy:
Unstained: sperm cells
Stained: blood cells small intestine tissue
o Fluorescence Microscopy:
Bombard with light of a certain wavelength-
Tag certain proteins in cells with fluorescence (glow when hit with certain wavelengths)
o Electron Microscopy- lining of trachea
Scanning Electron Microscope (SEM)- surface scan (used to see interaction with other cells)
Transmission Electron Microscope (TEM)- a ‘slice’ (can see organelles within cells)
Genetics (DNA, chromosomes)
In the 1930’s, these strands combined, which lead to modern advancs such as “dolly” and nanotechnology
bright field
phase contrast
DIC
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Document Summary

Historical light microscopy and the discovery of the cell cell theory facts, hypotheses, theories and the scientific method. Strands" of cell biology cytology, biochemistry, genetics. Basic properties shared by all cells classes of cells: prokaryotes - two kingdoms, eukaryotes- membrane-bound compartments, nucleus. Endomembrane system er, golgi, lysosomes, vesicles. Mitochondria, chloroplasts: origins of eukaryotic cells - endosymbiont theory cytoskeleton. Before microscope, it was not known that cells exsisted. Robert hooke (1635-1703) first microscope: viewed slices of cork found cellula (little rooms- actually saw cell walls) Antoni van leeuwenhoek (1632-1723: father of microbiology , worked with glass huge improvement in quality of lenses nearly 300x magnification became possible first to observe: (drew what he saw) single-celled organisms animalcules . Progress stalled for a century limited resolving power: emphasis on description rather than explanation (only drawings) Compound microscope (1830s) improved magnification and resolution: allowed visualization of objects less than 1 m.

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