- List the organelles of the cell and their functions.
- Discuss the structure and function of the cell membrane and cytosol.
- Describe the structure and function of the nucleus.
- Distinguish between plant and animal cells.
Check Your Understanding
- What is a cell?
- How do we visualize cells?
Introduction
Understanding the structure and function of cells is essential to understanding how living
organismswork. Cellbiologyiscentraltoallotherfieldsofbiology,includingmedicine. Many
human diseases and disorders are caused by the malfunction of people’s cells. Furthermore,
toxins in the environment often act on specific cellular processes. The healthy functioning
of the body and its organs is dependent on its smallest unit - the cell.
To better understand the biology of the cell, you will first learn to distinguish the two basic
categories of all cells: prokaryotic and eukaryotic cells. You will also learn what makes a
cell specialized; there are major differences between a “simple” cell, like a bacteria, and a
“complex” cell, like a cell in your brain. To understand these differences, you need to first
understand the basic components of the cell, which include the:
- Cell membrane
- Nucleus and chromosomes
- Other organelles
Prokaryotic and Eukaryotic Cells
There are two basic types of cells,prokaryotic cells(Figure3.8), which include bacteria
and archaea, andeukaryotic cells(Figure3.9), which include all other cells. Prokaryotic
cells are much smaller and simpler than eukaryotic cells; eukaryotic cells can be considered to
be “specialized.” Prokaryotic cells are surrounded by acell wallthat supports and protects
the cell. In prokaryotic cells the DNA, the genetic material, forms a single large circle that
coils up on itself. Prokaryotic cells also can contain extra small circles of DNA, known as
plasmids. The two types of organisms consisting of prokaryotic cells belong to the domain
Bacteria and the domain Archaea. These two domains were discussed in theIntroduction to
Living Thingschapter.