7-1: Life is Cellular
Biology 1
Introduction
• If you look closely at different
things, you will notice that
every living organism is made
of cells
Discovery of
Cell
• 1600: Robert Hooke makes
first microscope to look at
cork
• Noticed it was made of small
empty “boxes”
• “boxes” reminded him of
monastery rooms, called them
cells
Discovery of
Cell
• 1600: Anton van
Leeuwenhoek used
microscope to study pond
water
• Saw tiny living organisms in
the water
Discovery of
Cell
• 1838: Matthias Schleiden said
all plants are made of cells
• 1839: Theodor Schwann said
all animals are made of cells
• 1855: Rudolf Virchow said
new cells can only come from
other cells
Cell Theory
1. All living things are
composed of cells
2. Cells are basic units of
structure and function in
living things
3. New cells are produced
from old cells
Prokaryotes
and
Eukaryotes
• Cells have 2 categories:
1. PROKARYOTES: unicellular
organism lacking a nucleus
2. EUKARYOTES: organism
whose cells contain nuclei
• NUCLEUS (plural-nuclei): the center of
the atom which contains the protons
and neutrons; in cells, structure that
contains the cell's genetic material
(DNA) and controls the cell's activities
Prokaryotes
• Small and simple
• DO NOT HAVE NUCLEUS
• Can grow, reproduce, respond
to environment, and move
around
• EXAMPLE: BACTERIA
Eukaryotes
• Large and complex
• DO HAVE NUCLEUS
• Have lots of structures and
membranes inside, VERY
SPECIALIZED FOR SPECIFIC JOBS
• EXAMPLES: Protists, Plants,
Animal, Fungi