Cells & Life
Chapter 2
Lesson 1
cytology: the study of cells
Robert Hooke
Anton van Leeuvenhoek
Matthias Schleiden
Theodor Schwann
Rudolf Virchow
Robert Hooke
Cytology can be
traced back over
300 years to the
English scientist
Robert Hooke.
Robert Hooke
In 1665 he published
Micrographia - a
report of his use of
simple compound
microscopes capable
of magnifying
approximately
30 times to
observe cork.
Robert Hooke
The neat rows of
little boxes
reminded him of
rows in a prison
or a monastery he therefore
named the
"cells."
(“coined”)
Robert Hooke
In 1665 Robert
Hooke was the
first to use the
term cell.
He saw only the
dead, empty
walls of cork
cells.
Anton van Leeuwenhoek
Around the
same time as
Robert Hooke,
Anton van
Leeuwenhoek
also began to
observe tiny
objects with
microscopes.
Anton van Leeuwenhoek
He looked at
drops of lake
water, scrapings
from teeth and
gums, and water
from rain
gutters.
Anton van Leeuwenhoek
He saw tiny
moving
organisms
which he called
“animalcules,”
meaning “little
animals.”
Matthias Schleiden
A German
botanist
In 1838 said,
"All plants are composed of cells."
Theodor Schwann
A German
zoologist
In 1839 said,
"All animals are composed of cells."
Rudolf Virchow
A German
doctor who
is referred
to as the
"Father of
Pathology,"
In 1855 he proposed that new cells are
formed only from cells that already exist.
The three basic principles of
the cell theory
 All living things are made of one
or more cells.
 The cell is the smallest unit of
life.
 All cells come from preexisting
cells.
Understanding cells
How did scientists’ understanding of cells
develop?
Basic Cell Substances
 The main ingredient in any cell is water.
A water molecule has two areas:
 The negative (–) end can attract the positive
part of another substance.
 The positive (+)
end can attract
the negative part
of another
substance.
Basic Cell Substances
Water and salt both have positive and
negative parts.
Basic Cell Substances
Macromolecules are necessary substances in
cells, formed by joining many small
molecules together.
macromolecule
from Greek makro–, means “long”; and Latin
molecula, means “mass”
Basic Cell Substances
 There are four types of macromolecules in
cells:
• Nucleic acids are macromolecules that
form when long chains of molecules
called nucleotides join together. Two
types: DNA & RNA
• Proteins are long chains of amino acid
molecules. Proteins are involved in
almost everything that happens in a living
cell.
Basic Cell Substances
• Lipids are large macromolecules that
do not dissolve in water.
• Carbohydrates store energy, provide
structural support, and are needed for
communication between cells. Made of
CHO. Examples: sugar & starch
These are essential
molecules of life!
Each type of macromolecule has unique
functions in the cell.