Download Cell Theory LIVING ORGANISMS ARE MADE OF CELLS

Cell Theory
A well-substantiated
explanation of some aspect
of the natural world that is
repeatedly confirmed through
observation and
experimentation.
Hooke first described cells in
1665 after examining cork
and other plants with a
microscope, He saw a
TREND….
Which means, “To
have a general
tendency”
LIVING
ORGANISMS ARE
MADE OF CELLS
1.1.A1
Which allows for discrepancies
and/or exceptions to exist
Exception
Example
Caveat
The presence of extracellular
material in an organism
contradicts the idea that the
organism is made up of cells only
Very large cells with ONE nucleus
Vitreous humor of the eye,
mineral deposits in bone, cellulose
in plant cell walls
These materials were produced by
cells!
Very large cells with many nuclei
Muscle cells called fibres are very
long (≈30mm) and multinucleate
Giant algae like Acetabularia are
up to ≈ 100 mm with a single
nucleus
Giant algae like caulerpa are
among the biggest single cells in
the world (up to ≈ 1m)
Fungal hyphae with a continuous
cytoplasm and tubular cell wall
They are surrounded by a single
cell membrane and are formed by
division of preexisting cells.