BI 234 CHAPTER 3 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED
Describe, compare and contrast the structure of eukaryotic cells and prokaryotic
cells.
Prokaryotes do not have a nucleus or organelles. Eukaryotes have a nucleus and
compartmentalized organelles. The types of lipids in the membrane and cell wall (if
present) differ between the two.
Describe the basic structure of a bacterial cell.
All types have cell walls, Gram-positive have a thick cell wall and no outer membrane,
Gram-negative have a thin cell wall and an outer membrane, Prokayotic so no
membrane-bound organelles
Describe the structure and function of the glycocalyx. Differentiate between
capsule and slime layer.
an outer layer of polysaccharides, proteins, and polypeptides functioning to adhere to
environment and protection
capsule: dense and firmly attached to cell, common virulence factor in pathogens,
prevents detection of bacterium by immune system
slime layer: gooey, sticky, loose aggregate of sugar molecules
Compare and contrast the structure of fimbriae and pili. Describe their functions.
, fimbriae: sticky, bristle-like proteins used by bacteria to adhere to surfaces and creep
along . 100s per cell. some conduct electrical signals
pili: longer than fimbriae, bacteria typically have only one or two per cell, used to pull
two cells together and conjugation (bacterial sex)
Describe the function of flagella in bacteria.
responsible for movement, rotational action propels bacterium through environment,
rotation reversible; can be counterclockwise or clockwise
Describe polar, monotrichous and peritrichous flagellar arrangements.
Peritrichous flagella: covers the surface of the cell
Monotrichous: One flagella on one end
Polar: at one end of cell (can be a tuft)
Describe the arrangement of endoflagella (axial filaments). Describe the motility
that results from an axial filament.
a special flagellum of spirochetes that spirals tightly around the cell rather than
protruding from it. a structure composed of rotating endoflagella that allows a spirochete
to 'corkscrew' through it's environment.
Counterclockwise goes forward, clockwise goes to random directions
Explain why axial filaments (endoflagella) are found in Gram-negative bacteria but
not in Gram-positive bacteria.
WITH COMPLETE SOLUTIONS VERIFIED
Describe, compare and contrast the structure of eukaryotic cells and prokaryotic
cells.
Prokaryotes do not have a nucleus or organelles. Eukaryotes have a nucleus and
compartmentalized organelles. The types of lipids in the membrane and cell wall (if
present) differ between the two.
Describe the basic structure of a bacterial cell.
All types have cell walls, Gram-positive have a thick cell wall and no outer membrane,
Gram-negative have a thin cell wall and an outer membrane, Prokayotic so no
membrane-bound organelles
Describe the structure and function of the glycocalyx. Differentiate between
capsule and slime layer.
an outer layer of polysaccharides, proteins, and polypeptides functioning to adhere to
environment and protection
capsule: dense and firmly attached to cell, common virulence factor in pathogens,
prevents detection of bacterium by immune system
slime layer: gooey, sticky, loose aggregate of sugar molecules
Compare and contrast the structure of fimbriae and pili. Describe their functions.
, fimbriae: sticky, bristle-like proteins used by bacteria to adhere to surfaces and creep
along . 100s per cell. some conduct electrical signals
pili: longer than fimbriae, bacteria typically have only one or two per cell, used to pull
two cells together and conjugation (bacterial sex)
Describe the function of flagella in bacteria.
responsible for movement, rotational action propels bacterium through environment,
rotation reversible; can be counterclockwise or clockwise
Describe polar, monotrichous and peritrichous flagellar arrangements.
Peritrichous flagella: covers the surface of the cell
Monotrichous: One flagella on one end
Polar: at one end of cell (can be a tuft)
Describe the arrangement of endoflagella (axial filaments). Describe the motility
that results from an axial filament.
a special flagellum of spirochetes that spirals tightly around the cell rather than
protruding from it. a structure composed of rotating endoflagella that allows a spirochete
to 'corkscrew' through it's environment.
Counterclockwise goes forward, clockwise goes to random directions
Explain why axial filaments (endoflagella) are found in Gram-negative bacteria but
not in Gram-positive bacteria.
