Skip to main content
Back

Microbiology: Prokaryotic Cell Structure and Function

1 student found this helpful
Control buttons has been changed to "navigation" mode.
1/21
  • Key differences between prokaryotic and eukaryotic cells

    Prokaryotic cells lack a nucleus and membrane-bound organelles, reproduce by binary fission, and have simpler structures. Eukaryotic cells have a nucleus, organelles, and reproduce by mitosis or meiosis.

  • Major internal structures of prokaryotic cells

    Include the cytoplasm, ribosomes, nucleoid (DNA region), and sometimes endospores.

  • Major external structures of prokaryotic cells

    Include glycocalyx (slime layer or capsule), flagella, axial filaments, fimbriae, and pili.

  • Which prokaryotic structures are always present?

    All bacteria have a plasma membrane, ribosomes, cytoplasm, and a cell wall (except some like Mycoplasma). Other structures like flagella and pili are optional.

  • Function and form of glycocalyx

    The glycocalyx is a sticky outer layer; the capsule is organized and protects against phagocytosis, while the slime layer is loose and helps in attachment.

  • Function of bacterial flagella

    Flagella are long, whip-like structures used for motility, allowing bacteria to move toward or away from stimuli.

  • Role of axial filaments

    Axial filaments are internal flagella found in spirochetes that enable corkscrew movement.

  • Purpose of fimbriae

    Fimbriae are short, hair-like structures that allow bacteria to adhere to surfaces and each other.

  • Function of pili

    Pili are longer than fimbriae and facilitate DNA transfer between bacteria during conjugation.

  • Structure and function of the bacterial cell wall

    The cell wall provides shape and protection; it is made of peptidoglycan in bacteria.

  • Difference between Gram-positive and Gram-negative cell walls

    Gram-positive walls have thick peptidoglycan layers; Gram-negative have thin peptidoglycan and an outer membrane. This affects antibiotic susceptibility and disease mechanisms.

  • How does osmosis work in bacterial cells?

    Osmosis is the passive movement of water across a membrane from low to high solute concentration without energy.

  • What is simple diffusion?

    Simple diffusion is the passive movement of small or lipid-soluble molecules across membranes down their concentration gradient.

  • How does facilitated diffusion differ from simple diffusion?

    Facilitated diffusion uses protein channels or carriers to move molecules down their gradient without energy.

  • What is active transport in bacteria?

    Active transport moves molecules against their concentration gradient using energy, usually ATP.

  • Why do active transport systems need energy?

    Because they move substances from low to high concentration, which is against the natural gradient and requires cellular energy.

  • Composition of acid-fast bacterial cell walls

    Acid-fast bacteria have waxy mycolic acid in their cell walls, making them resistant to staining and some antibiotics.

  • How do Archaea cell walls differ from typical bacteria?

    Archaea lack peptidoglycan and have unique cell wall components like pseudopeptidoglycan or other polymers.

  • What is unique about Mycoplasma cell walls?

    Mycoplasma lack a cell wall entirely, making them resistant to antibiotics targeting cell wall synthesis.

  • Common bacterial shapes

    Bacteria commonly have three shapes: coccus (spherical), bacillus (rod-shaped), and spirillum (spiral-shaped).

  • Common bacterial arrangements

    Arrangements include chains (strepto-), clusters (staphylo-), pairs (diplo-), and tetrads (groups of four).