Bacterial Cell Structure and Function Flashcards

Bacterial Cell Structure and Components

• Basal Body: Anchors the flagellum to the cell envelope with two to four rings on a rod.
• Bacillus: Refers to bacteria with a rod-like shape.
• Capsule: A glycocalyx structure made of mucopolysaccharides that aids in evading phagocytosis and antibody binding.
• Cell Envelope: Comprises all outer layers of a bacterium, providing protection and structural integrity.
• Cell Wall: A rigid layer outside the plasma membrane that shapes and strengthens bacterial cells.
• Cytoplasm: Enclosed by the cytoplasmic membrane, containing all cellular components.
• Colony: A cluster of bacteria originating from a single parent cell.
• Endospores: Resistant, dormant cell forms that allow bacteria to survive unfavorable conditions.

Mobility and Structure

• Chemotaxis: Movement driven by chemical stimuli; important for bacterial navigation.
• Coccus: Describes round-shaped bacteria.
• Flagella: Structures used for locomotion, differing in arrangement among bacterial types.
• Filament: The primary part of flagella, consisting of helical flagellin proteins that enhance motility.
• Hook: A joint structure connecting the flagellum's filament to the basal body, allowing rotation.

Cell Wall Characteristics

• Gram's Stain: A technique categorizing bacteria based on cell wall composition, facilitating identification.
• Gram-negative Bacteria: Have a complex cell wall with less peptidoglycan and are often more virulent.
• Gram-positive Bacteria: Have a simpler wall structure with more peptidoglycan, generally less toxic than gram-negative counterparts.
• Peptidoglycan: A critical component of bacterial cell walls that provides structural integrity and protection against lysis.

Toxins and Immune Response

• Endotoxin (Lipid A): A component of gram-negative bacteria's outer membrane that triggers strong immune reactions, potentially leading to septic shock.
• Granules/Inclusions: Energy reserves made of polysaccharides or polyphosphates, utilized by cells during energy stress.

Additional Structures

• Fimbriae (Pili): Hair-like structures essential for attachment to surfaces and each other, influencing colonization and infection.
• Lysis: The breaking down of cells, which can occur due to various damaging events.

Each of these components plays a vital role in the survival, reproduction, and pathogenicity of bacteria. Understanding these elements is crucial in microbiology and medical applications.