Bacteria on Earth

Bacteria are in every environment imaginable!

Bacterial Morphology

•largest – 50 μm indiameter

• smallest – 0.3 μm in diameter

Figure 3.3

Thiomargarita namibiensis

Gram Staining

Gram Staining

Gram-Positive

Peptidoglycan

Cell Membrane

Peptidoglycan

Cytoplasmic membrane

Another cell

Gram-Negative

Outer Membrane

MembranePeptidoglycan

Peptidoglycan

Periplasm

Periplasmic space

Figure 3.4 – Effect of Pencillin

Endospore

Bacterial Reproduction

Treponema denticola

Predatory Bacteria

Bdellovibrio bacteriovorus attacking Spirillum serpens (arrow).