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Journey into the Cell
Eukaryotic and Prokaryotic Cells
 Related Resources
• Journey into the Cell
• Nucleus
•  Ribosomes
•  Mitochondria
• Endoplasmic Reticulum
•  Golgi Complex
•  Lysosomes
•  Peroxisomes
•  Cytoskeleton
•  Cilia and Flagella
 
Life is both wonderful and majestic. Yet for all of its majesty, all organisms are composed of the fundamental unit of life, the cell. The cell is the simplest unit of "matter" that is alive. From the unicellular (uni-) bacteria to multicellular animals, the cell is the organizational principle for biology. Let's look at some of the components of this basic organizer of living organisms.

Types of Cells

There are two primary types of cells: prokaryotic cells and eukaryotic cells. (See Bio-Word Dissections for additional information about biological naming conventions.) Prokaryotic cells have no true nucleus while eukaryotic cells have a true nucleus. There are many distinctions between these two different types of cells as summarized by this table:


Structure
Prokaryotic Cell
Typical Animal Eukaryotic Cell
Cell Wall
Yes
No
Centrioles
No
Yes
Chromosomes One long DNA strand
Many
Cilia or Flagella
Yes, simple
Yes, complex
Endoplasmic Reticulum
No
Yes (some exceptions)
Golgi Complex
No
Yes
Lysosomes
No
Common
Mitochondria
No
Yes
Nucleus
No
Yes
Peroxisomes
No
Common
Plasma Membrane
Yes
Yes
Ribosomes
Yes
Yes


Only bacteria and cyanobacteria are prokaryotes. Animals, plants, fungi and protists are eukaryotes. Eukaryotic and prokaryotic cells also differ in size. On average, prokaryotic cells are about 10 times smaller in diameter than eukaryotic cells.

Next page > Differences between plant and animal eukaryotic cells > Page 1, 2

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