2010 bio 113 (1) - Chapter 6 A Tour of the Cell Important...

Chapter 6:
A Tour of the Cell

Important Point:

Most Cells are Small
Note relative size of
bacteria (~1/10 size
of animal/plant cells)
Frog eggs 100-times &
chicken egg 1000-
times larger than most
plant and animal cells
Note relative size
of nucleated cells
Note relative size of
viruses (~1/1000 size
of animal/plant cells)

More Size Comparisons
“…any one
cell
embodying
as it does the
record of a
billion years
of evolution,
represents
more an
historical
than a
physical
event….
You cannot
expect to
explain so
wise an old
bird in a few
simple
words.” Max
Delbrück (as
quoted by
Stent, in
Max
Delbrück,
1906-1981,
1982,
Genetics
101:1-16)
Cells are
membrane
-enclosed,
DNA-
containing,
metabolizi
ng, and
self-
replicating

Surface-to-Volume Ratio
Rate of “stuff” movement
across membranes can be
limited by amounts of
membrane: solved by smaller
cells or with more membrane

A Prokaryotic Cell
No nucleus
Typically no membrane-
bound organelles

Plasma Membrane
Surrounds cytoplasm, a.k.a.,
cytoplasmic membrane
More in Ch. 7
Defines the limits of individual cells

An Animal Cell
(typical)
See (and memorize) p.
100 for descriptions

A Plant Cell (typical)
See (and memorize)
p. 101 for descriptions
You should know what
all of these things are
as presented in these
figures in your book

Compartmentalization

Eukaryotic cells
are full of
membrane-
enclosed
compartments

These separate
incompatible
chemical and
physical
conditions

That way, for
example, proteins
can be both
synthesized and
hydrolyzed within
a single cell

Endomembrane System
error
Surrounds
cytoplasm, a.k.a.,
cytoplasmic
membrane