Download Introduction to Cells

Chapter 7 – Cell Structure and
Function
7.1 Life is Cellular
7.1 Life is Cellular
The Discovery of the Cell
Exploring the Cell
Prokaryotes and Eukaryotes
The Discovery of the Cell
 Early Microscopes, 1660s
Robert Hooke used an early compound microscope to
observe a thin slice of cork, a plant material.
 made of thousands of tiny chambers called cells
Anton van Leeuwenhoek used a single lens
microscope to observe pond water and other things
He discovered cells to be everywhere.
The Cell Theory
a fundamental concept of biology
 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.
 All cells contain genetic information.
Exploring the Cell/ Types of Microscopes
 Biologists still use the microscope to explore cells,
however microscopes of today are much more
powerful.
 Fluorescent labeling and light microscopy:
enables moving molecules to be followed through
the cell.
 Confocal light microscopy: scans cells with a laser
beam creating 3-D images
 High-resolution video technology: produce movies
of cells
 Electron microscopes:
 Transmission electron microscopes (TEMs): make it
possible to explore cell structures and large
proteins.
 Scanning electron microscopes (SEMs): a pencillike
beam of electrons is scanned over the surface of the
specimen.
Prokaryotes and Eukaryotes
 Cells fall into two broad categories depending on
whether or not they have a nucleus.
 Nucleus: a large membrane-enclosed structure
that contains the cell’s genetic material in the
form of DNA.
 Membrane: a thin layer of material that serves
as a covering or lining.
 Eukaryotes: cells that contain nuclei
 Prokaryotes: cells that do not contain nuclei.
Prokaryotes
Generally smaller and
simpler than eukaryotes.
They have genetic material
that is not contained in a
nucleus.
Carry out every activity
associated with living things.
They grow, reproduce, respond
to the environment, and some
move.
This group includes bacteria.
Eukaryotes
 Larger and more complex then prokaryotes.
 Generally contain dozens of structures and
internal membranes that are highly specialized.
 Contain a nucleus in which their genetic material
is separated from the rest of the cell.
 Make up plants, animals, fungi, and protists.