Download Intro to Cell Structure

Cell Structure
Introduction to
Cells
Objectives of this Chapter
 Describe relationships between structure and
function at the cellular and sub-cellular levels of
an organism
 Express the common features of cells and the
major differences between prokaryotes and
eukaryotes
 Outline how proper functioning of all cell
structures is needed to maintain homeostasis
Cell Example - Paramecium
 Found in ponds and
streams
 Classic example of a a
eukaryotic cell
 Nucleus (actually has more
than one)
 Moves by cilia
 Contractile vacuoles
squeeze excess water out
of cell
What are these cells?
Use their structure to predict their function
What are these cells?
Again – use their structure to predict their function…
More cells
Structure = Function
Cell Features - Objectives
 List the 3 parts of the cell theory
 Determine why cells must be relatively small
 Compare the structure of prokaryotic cells with
the structure of eukaryotic cells
 Describe the structure of cell membranes
Cell Theory -1800s - Schleiden,
Schwann and Virchow
 All living things are made
of one or more cells.
 Cells are the basic units of
structure and function in
living organisms.
 All cells arise from existing
cells
Why are cells so small?
Small cells function more
efficiently than large cells
 Most cells range in size from
5 micrometers to 20
micrometers in diameter.
 100 trillion cells in the human
body
 All substances must enter
and leave cell through the
membrane
 Small cells can transport
material more easily
because of surface area to
volume ratio
Surface Area to Volume Ratio