Download The Cell The Discovery of the Cell The Discovery of

The Cell
7.1 Discovery of the Cell
The Nora School
Biology
955 Sligo Avenue
Silver Spring, Maryland 20910
Period ________
The Discovery of the Cell
• Because there were no
instruments to make cells
visible, the existence of cells
was unknown for most of human
history.
• This changed with the invention
of the microscope.
• In 1665, Robert Hooke used an
early compound microscope to
look at a thin slice of cork, a
plant material.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
The Discovery of the Cell
• At the same time, Anton
van Leeuwenhoek used
a single-lens microscope
to observe pond water
and other things.
• The microscope
revealed a world of tiny
living organisms.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
1
The Cell Theory
•
•
Cells are the basic units
of life.
The Cell Theory is a
fundamental concept of
biology. It states:
1.
2.
3.
All Living Things are composed
of cells.
Cells are the basic units of
structure and function in living
things.
New cells are produced from
existing cells.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
Electron Microscopes
• Electron microscopes reveal
details 1000 times smaller than
those visible in light
microscopes.
• Electron microscopy can be
used to visualize only nonliving,
preserved cells and tissues.
– Transmission electron microscopes
(TEMs)
– Scanning electron microscopes (SEMs)
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
Prokaryotes and Eukaryotes
• Typical cells range in size from 5 to 50
micrometers.
• The nucleus is a large membrane-enclosed
structure that contains the cell’s genetic
material in the form of DNA.
• Cell typing is categorized by their nucleus:
– Eukaryotes (Greek for “true nucleus/center”)
– Prokaryotes (Greek for “before nucleus/center”)
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
2
Prokaryotes and Eukaryotes
• Prokaryotic cells have
genetic material that
is not contained in a
nucleus.
• Eukaryotic cells
contain a nucleus in
which their genetic
material is separated
from the rest of the
cell.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
Eukaryotic Cell Structure
• These cells are highly complex with
different “organelles” that work together
within the cell.
– Organelles are specialized organs that
have different roles within the cell.
– The Eukaryotic cell is generally broken
down into two parts:
• Nucleus
• Cytoplasm
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
Section 7.1 Assessment
1. What three statements describe the Cell
Theory?
2. What are the differences between
prokaryotic cells and eukaryotic cells?
3. Compare the process used to produce a
TEM and an SEM.
4. What structures do all cells have?
5. How did the invention of the microscope
help the development of the Cell Theory?
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Biology
Period ________
3