Cell Structure and Function
There are two types of cells: Prokaryotes and
Eukaryotes
Typically cells ranges from 5 to 50 micrometers in
diameter, the smallest Mycoplasma bacteria are
only 0.2 micrometers across, and even the best
light microscopes can barely see so small them.
The biggest cell, a giant
amoeba Chaos chaos may be
1000 micrometers in
diameter, which is large
enough to be seen unaided
as a tiny speck in pond
water.
Despite the differences in
sizes, ALL cells contain the
molecule that carries biological information –
DNA.
In addition, a thin flexible barrier called a cell
membrane surrounds all cells.
Cells fall into two broad categories. It all depends
on whether they contain a nucleus.
 The nucleus is a large
membrane-enclosed
structure that contains the
cell’s genetic material in
the form of DNA. The
nucleus controls many of
the cell’s activities.
Eukaryotes:
 Cells that enclose their DNA in nuclei.
 Generally larger and more complex than
prokaryotic cells.
 Contains dozens of structures and internal
membranes.
 Contains MEMBRANE BOUND
ORGANELLES
 Many are highly specialized.
 Eukaryotes:
o Plants
o Animals
o Fungi
o Protists
 Cell Organization
o What is the role of the cell nucleus?
 Contains nearly all of the cell’s DNA
and, with it, the coded instructions
for making proteins and other
important molecules.
o Can be divided into two major parts: the
nucleus and the cytoplasm.
 Cytoplasm is the fluid portion of the
cell outside the nucleus
o Contains organelle, “little organs” that
perform specialized functions within the
cell itself.
 Living version of a modern factory
o Specialized machines and assembly lines
of the factory are analogues to the
difference organelles of the cell.
o Follow instructions and produce products
Prokaryotes
 Cells that do not enclose DNA in nuclei
 Generally smaller and simpler than
eukaryotic cells
 Prokaryotes grow, reproduce, and respond to
their environment, or even swim despite how
simple they are!
 Bacteria are prokaryotes!!
 DO NOT CONTAIN A NUCLEUS!!!!!
 Have cytoplasm as well, even though they
have no nucleus.
 Contains organelles just like eukaryotic cells,
some are the same; some are different. More
to come on that!
 Contains NO MEMBRANE BOUND
ORGANELLES
Little known facts about cells:
1) Cells have varying life spans
a. Based off of the type and function of the
cell
b. Anywhere from a few days to a year.
Digestive tract cells live only a few days,
while the immune system can live up to 6
week. Pancreatic cells can live for as long
as a year.
2) Cell commit suicide
a. A cell become damaged or undergoes
some type of infection, it will self-destruct
by a process called apoptosis. It is used to
ensure proper development and to keep
the body’s natural process of cell division
in check.
3) There are more bacterial cells in the body
than human cells.
a. 95% of all cells are bacteria cells, with the
vast majority being in the digestive tract.
Use the textbook to work with your lab groups to
complete the sketches and question in the Cell
Parts Study Guide!
Cell Story Project:
 Create a story with the cell parts and
functions. See rubric for details!