Biomedical Engineering Reference
In-Depth Information
As we learn more and more about cells and the chemistry of life, we gain
correspondingly more opportunities to biologically alter ourselves and the
rest of the living world. reshaping life wisely requires biologically literate
non-biologists to make decisions about how biotechnologies are developed
and used. This is why knowing about cells and molecules matters. more-
over, learning about the beauty of life beyond what our unaided eyes can
see is fun. And life should be fun. so let's get started and jump right into
the world of the cell. The following questions will guide our foray into the
microscopic and submicroscopic realms of biology:
1. What are cells and molecules?
2. What do cell biologists do?
3. how is cell structure related to cell function?
4. What are the relationships between
DNA,
genes,
chromosomes,
and
ge-
nomes
?
5. What is the
central dogma of biology
?
6. What is the
genetic code
?
7. how do cells reproduce?
8. When and how did the first cells originate?
9. What do cells have to do with human values?
Cells and molecules
Just as different types of buildings are units of a city, cells are the struc-
tural and functional units of all living things on earth. But unlike build-
ings, all cells come from pre-existing cells. Together, these two statements
about cells constitute the “cell theory.” The first, that all living things are
comprised of cells, was proposed for plants in 1838 by a German botanist,
matthias schleiden, and for animals in 1839 by schleiden's zoologist col-
league, Theodor schwann. The second statement, that only cells beget cells,
was proposed in 1855 by the German pathologist rudolf virchow. Direct
observations and experimental data soon elevated the original propositions
of schleiden, schwann, and virchow to the level of theory, with a certainty
comparable to that enjoyed by the heliocentric theory for the solar system
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