Structure and Function of the Bacterial Cell

Question 1

Most clinically relevant bacterial species range in size

from:

Answer 1

m 0.25 to 1 µm in width and 1 to 3 µm in length

Question 2

fundamental staining technique of Bacteria

Answer 2

Gram’s stain

Question 3

the outermost structure of the bacterial cell

Answer 3

cell envelope

Question 4

components of the cell envelope:

Answer 4

• An OUTER MEMBRANE (in gram-negative bacteria
only)
• A CELL WALL composed of the peptidoglycan macromolecule (also known as the murein layer/peptidoglycan layer)
• PERIPLASM/PERIPLASMIC SPACE (in gram-negative bacteria only)
• The CYTOPLASMIC (INNER)/CELL MEMBRANE, which encloses the cytoplasm

Question 5

composition of OUTER MEMBRANE:

Answer 5

• bilayered structure composed of lipopolysaccharide — makes gram (-) net negative charge
• lipopolysaccharide macromolecules (PORINS)
  *

Question 6

gives the bacterial cell shape and strength to withstand changes in environmental osmotic pressures that
would otherwise result in cell lysis

Answer 6

cell wall (murein/peptidoglycan layer)

Question 7

structure of the cell wall (murein/peptidoglycan layer)

Answer 7

disaccharide-pentapeptide subunits:

N-acetylglucosamine and N-acetylmuramic (in alternate arrangement/MOIETIES)

Question 8

bounded by the internal surface of the outer membrane and the external
surface of the cellular membrane

Answer 8

periplasm/periplasmic space

** THIS AREA CONTAINS THE MUREIN LAYER

Question 9

deepest layer of the cell

envelope

Answer 9

cytoplasmic (inner) membrane

Question 10

functions of cytoplasmic (inner) membrane

Answer 10

• Transport of solutes into and out of the cell
• Housing of enzymes involved in outer membrane
synthesis, cell wall synthesis, and the assembly and
secretion of extracytoplasmic and extracellular
substances
• Generation of chemical energy (i.e., ATP)
• Cell motility
• Mediation of chromosomal segregation during
replication
• Housing of molecular sensors that monitor chemical and physical changes in the environment

Question 11

structure/cell appendage that is immediately exterior to the murein layer of gram-positive bacteria and the outer membrane of gram-negative bacteria

Answer 11

capsule (O antigen)/slime layer

—composed of high-molecular-weight
polysaccharides

Question 12

hairlike, proteinaceous structures that extend from the cell membrane into the external environment

Answer 12

fimbriae/pili

Question 13

present only in cells that

produce a protein referred to as the F factor

Answer 13

sex pilus

— F-positive cells initiate mating or conjugation only with F-negative cells, thereby limiting the conjugative process to cells capable of transporting genetic material through the hollow sex pilus