6.02 Bacteria: Life Inside One Cell - The Bacteria Cell Shapes Text-Only Version

• Coccus (spherical) - Here you see a culture of hundreds of Streptococcus mutans. This bacterium is responsible for the cavities in your teeth. It causes tooth decay. Notice that each individual bacterial cell is round.
• Bacillus (rod shaped) - Escherichia coli is one of hundreds of strains of this bacterium. Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin which can cause severe illness.
• Spirillum (spiral or corkscrew shaped) - Here you see two spirals of the bacterium Treponema palidum, the bacterium that causes the sexually transmitted disease syphilis.

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