S TUDY HINT
The basic concept introduced in these modules is that the prokaryotes
(Kingdom Monera) are a very diverse group made up of the eubacteria
and the archeabacteria.
Questions & Answers
Explain how each of the following characteristics contributes to the
success of prokaryotes: cell wall, capsule, flagella, fimbriae, endospores:
Cell wall: maintains cell shape; provides physical protection; prevents cell
from bursting in a hypotonic environment;
Capsule: enables cell to stick to substrate or to other individuals in a
colony; shields pathogens from host’s defensive cells;
Flagella: provide motility, enabling cell to respond to chemical or physical
signals in the environment that lead to nutrients or other members of their
species and away from toxic substances;
Fimbriae: allow cells to attach to surfaces, including host cells, or to each
other; Endospores: withstand harsh conditions.
Explain why the prokaryotes, Bacterial and Archae, are not in the same
Bacteria and Archaea have many significant differences, which clearly
place them in different domains. Each domain has unique rRNA
sequences, but the archaea and eukaryotes have some that match.
Bacteria have one kind of RNA polymerase, whereas archaea and
have several. Introns are rare in bacteria, present in most eukaryotic
genes, and found in some genes of archaea. Bacteria have peptidoglycan
in their cell walls, archaea have a related molecule, and the eukarya can
have cellulose or chitin. Histones are associated with eukaryotic DNA but
not bacterial DNA; some species of Archaea have histones.
Explain why bacteria populations can adapt rapidly to changes in their