Chapter 4: An Introduction to Cell Structure and Host-Pathogen Relationships

Vocabulary practice flashcards covering cell structure, bacterial taxonomy, staining methods, pathogenicity, virulence, and eukaryotic organelles from Chapter 4.

Prokaryotes

Living organisms that lack membrane-enclosed organelles.

Eukaryotes

Living organisms that contain membrane-enclosed organelles.

Bacillus

A rod-shaped bacterial cell morphology.

Coccus

A spherical bacterial cell morphology.

Spiral Bacteria

Bacteria that possess a spiral-shaped cell morphology.

Major Bacterial Shapes

Morphological classifications of bacteria, including coccus, rod, coccobacillus, fusiform bacillus, vibrio, spirillum, and spirochete.

Diplococcus

An arrangement of spherical bacteria (cocci) occurring in pairs.

Tetrad

An arrangement of spherical bacteria (cocci) occurring in groups of four.

Streptococcus

An arrangement of spherical bacteria (cocci) forming chains.

Staphylococcus

An arrangement of spherical bacteria (cocci) forming grape-like clusters.

Aggregates of Cocci

Cellular groupings formed by spherical bacteria, including diplococcus, tetrad, streptococcus, and staphylococcus.

Simple Stain

A bacterial staining technique that uses only one dye.

Differential Stain

A bacterial staining technique that uses more than one dye to differentiate between organisms or cellular components.

Gram Stain

A differential staining procedure that divides bacteria into four major groups (Gram-positive, Gram-negative, Gram-variable, and Gram-nonreactive) based on cell wall differences.

Negative Stain

A staining technique that colors the background surrounding encapsulated bacteria, making the capsule visible as a virulence factor.

Flagella Stain

A staining procedure that identifies bacterial flagella, which grant motility and allow pathogens to spread from an initial infection site.

Ziehl-Neelsen Acid-Fast Stain

A differential stain using heat to detect Mycobacterium species possessing mycolic acid in their cell walls, which retain dye after acid washing.

Endospore Stain

A differential staining technique that utilizes heat to allow dye penetration through the tough wall of dormant bacterial endospores.

Pathogens

Organisms that cause infectious diseases in host organisms.

Mutualism

A biological interaction where microbes and the host organism provide reciprocal benefits to one another.

Opportunistic Pathogens

Microorganisms that cause disease by taking advantage of a host's increased susceptibility or compromised immune state.

Primary Pathogens

Microorganisms capable of causing disease in healthy hosts by employing evolved mechanisms to overcome host defenses.

Virulence

The degree of pathogenicity or fitness of an organism when fighting host defenses and producing damage.

Pathogenicity Islands

Clusters of virulence genes located on bacterial chromosomes or plasmids that can be transferred between cells.

Quorum Sensing

A cell-density-dependent sensing mechanism where bacteria use specialized proteins to coordinate gene expression, such as toxin production in Salmonella.

Biofilm

Aggregated assemblies of bacteria that attach to surfaces, capture nutrients, impair antibiotics and disinfectants, and inhibit host phagocytosis.

Cytoskeleton

A eukaryotic structural framework made of microfilaments, intermediate filaments, and microtubules that supports cell shape, cell division, and tissue linkage.

Cilia

Microtubule projections on the eukaryotic cell surface that move trapped particles upward and out of regions such as the lower respiratory tract.

Endosymbiotic Theory

The evolutionary concept proposing that mitochondria originated from ancestral bacteria integrated into eukaryotic cells.

Lysosome

A membrane-bound vesicle loaded with destructive enzymes and chemicals that destroys invading pathogens and recycles host components.

Proteasome

An organelle that degrades and recycles cellular proteins and breaks down pathogen proteins to trigger host immune responses.

Peroxisome

An organelle involved in fatty acid degradation containing catalase to neutralize hydrogen peroxide by-products.

Pinocytosis

A form of endocytosis where host cells take in extracellular fluid and dissolved small particles into vesicles.

Phagocytosis

A form of endocytosis where host cells extend pseudopodia to engulf large particles or entire pathogens into vesicles.

Pinocytosis vs Phagocytosis

Mechanisms of endocytosis distinguishing fluid uptake via small vesicles (pinocytosis) from engulfment of large particles or pathogens via pseudopodia (phagocytosis).