Bil 255
- Cell and Molecular Biology...
structure, function, & the molecules of cells |
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Professors
Glaser
and
Mallery
Spring and Fall Semesters
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C1...
pages 1-30
Description...
The goal of
cell & molecular biology is to understand the
molecular basis of cell function and the
fundamental cellular processes ranging
from cell division and
protein trafficking to
signal
transduction
and
cell migration,
to the
formation of tissues during development and
wound
healing. The
experimental
approaches used in studying
cell regulation and function
are
multidisciplinary and include:
biochemical and biophysical
experimentation
and molecular and genetic manipulation of functions at both the
cellular
and
organismal levels.
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CMB uses a
REDUCTIONIST
philosophy…
the
definitive
methodological approach
of 20th century science.
REDUCTIONISMg* is
a fundamental
research protocol of CMB
i.e., "
knowing the parts may explain the function of
the whole "
a bottoms-up approach - " one can't truly understand what
one can't build "
can we construct a living cell 'off
the shelf' from its molecular parts? |
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some personal relevance...
my mother
(nee 1906):
saw advent
of auto, airplane, radio, T.V., man on the moon...
CMB
gave us...
the
Central
Dogma of
molecular biology
DNA -->
RNA -->
Protein
mcb fig 4.1*
"Life
begets Life "
- is now seen at the molecular level,
as the faithful
replication of DNA...
CMB asks...
what do all cells have
in common...
the answer =
"their molecules & chemical
reactivity"
their biochemistry:
proteins,
lipids, carbs are all the same...
we need to understand
Molecular Biology
to see how life works
CMB
is about
energy &
reactivity,
movement
&
change,
action
&
reaction;
almost everything that happens in life.
happens in cells...
which likely boils down to
ENZYME CATALYSIS.
CMB
replaces the
gross
anatomy and
physiological
studies of the 17th & 18th century,
with
the biology of molecules &
molecular systems
in 21st century.
but
as
Erwin
Chargaff (former Chair of Bioc @ Columbia U;
pic
Heineken
Prize winner)
has said,
"
CMB... is
the practice of Biochemistry without a license "
end1
CMB is rooted in the 2 major theories of Biology...
1.
Evolution - Darwinian Natural Selection.
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Consequences
of Cell Theory:
Cell
Theory
replaces
Vitalism*...
which was
the mainstream
scientific thought of 18th century,
Vitalism
was the school of scientific thought, that attempted to explain the
nature of life
as resulting from a
vital
force,
"a soul", peculiar to living
organisms and different
from all other physical forces found outside living things.
entirely by the workings of laws of
chemistry
and
physics
without a
‘vital force’.
VITALISM
vs.
MECHANICALISM
living
vs.
non-living
organic vs.
non-organic
Vital Force vs.
no vital force
"There are
no laws
of Chemistry or
Physics unique only to the living
condition.
"
The cell
is the fundamental unit of all life,
and though MAN &
MOUSE have
very different anatomical structure,
their cells & organelles are
the same,
and on a letter-for-letter basis 85% of their
genes
are the same,
thus
studying cells in one organism has direct application to other organisms.
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Cell Types
& The
Tree of Life |
 |
(refer to chapter 1) |
All living CELLULAR ORGANISMS may be
grouped into...
3 DOMAINS
NAS-8
EUBACTERIA
-
true bacteria
ARCHAEA
-
ancient prokaryotes
[
Kingdoms pic &
collage ]
EUKARYOTA - modern eukaryotes
Carl
Woese, (an
interview)
compared the nucleotide sequence of the single
small-unit
rRNA*
from many species...
rRNA is found in all cells and therefore,
if all cells
are derived form a common progenitor[NAS-1],
their sequence changes
over time can indicate divergence
(loss of relatedness) through phylogeny (family trees)
The
RNA phylogeny tree produced, by comparing similar & divergent sequences,
a tree with 3
distinct branches (Domains) (mcb
fig
1.3*)
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but within
the 3 domains there are
only
2 successful Plans of Cellular Organization
distinguished primarily by size & the type of
internal
structures (the organelles) they possess:
1. PROKARYOTE
- "pro" = before + "karyon"
= nucleus... includes
archaea bacteria &
today's prokaryotes also include
blue green algae,
bacteria,
&
eubacteria-fig 1.1b
includes members of the original Kingdom monera, now Kingdoms Archaea &
Bacteria.
they lack
significant membrane bound organelles
genes contain "naked DNA" -,
i.e., there are no "chromosomes*?"
little to no internal compartmentation
fig 1.2a* +
E.coli*
size range -
0.1 to 10 µm diameter
3 primary cellular shape in prokaryotic cells:
-
cocci,
bacilli, spirochetes* |
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2.
EUKARYOTIC [eu
-true
karyon
-nucleus...] cell plan
of multi-cellular organisms
eukarya: includes the algae
& protozoa,
fungi &
slime molds, & all plants
& animals.
[ 4 Kingdoms of Protista, Fungi, Plantae, & Animalia ]
7
common CHARACTERISTIC of EUKARYOTES:
nucleus - 'may have been single greatest step in evolution of higher animals'
genes in "chromosomes*"...
colored bodies... made of DNA + protein [karyotype*]
contains more DNA
(1,000x more) than prokaryotes
extensive
internal membranes -
endomembrane
system*
(nuclear memb + ER + Golgi + vesicles)
presence of
organelles- significant internal compartmentalization of function
organelle
- a subcell part that
has a distinct metabolic function
presence of
flexible cell walls (allows
endocytosis/phagocytosis*) especially in animal cells
presence of
cytoskeleton*
(provides framework to be larger & provide
form/shape)
reproduce
sexually
usually
larger - cell
volume 10X > than bacteria -
size 5.0 to 20 µm diameter
mcb6e fig
9.1: schematic drawings of
animal*
&
plant*
cells
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µ
Model Organisms*
cheap, plentiful, prolific reproducers, with simple genomes
& unique properties
for practical research analysis:
[see pg 25 - 28]*
cell & molecular biology's research model organisms
have
included:
Giardia - a primitive eukaryotic
cell,
an anaerobic protozoan cell with 2 nuclei
[Giardiasis]
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