Characteristics of Bacteria
Bacteria resemble plants in that they have rigid cell walls, although the walls
are generally of nitrogen rather than cellulose. Some forms have flagella,
while others are non motile. Bacteria have ribosomes and nucleic acids but
lack mitochondria, plastids, and the central vacuole. Bacteria are distinguished
from each other, in part, on the basis of their shapes. Rod-shaped
bacteria are called
bacilli, round forms are called
cocci, and curved forms are
called
spirilli. Cocci can occur in pairs (
diplococci), clusters (
staphylococci), or chains (
streptococci).
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| Figure 11-2 Types of bacteria. |
