Cell StructureIntroduction 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 cellsStructure = 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