study guide 1

Flashcards covering key terms and definitions related to prokaryotes, bacterial morphology, staining techniques, and host-pathogen interactions.

Prokaryotes

Organisms without a true nucleus, with DNA in a nucleoid, and lacking membrane-bound organelles.

Eukaryotes

Organisms with a true nucleus containing enclosed DNA and numerous membrane-bound organelles.

Streptococcus

A spherical bacterium arranged in chains, often described as a 'chain of pearls.'

Staphylococcus

A spherical bacterium arranged in tight clusters resembling grapes.

Gram Stain

A common staining technique used to differentiate bacteria based on their cell wall structure.

Gram-Positive Bacteria

Bacteria characterized by a thick peptidoglycan wall that retains the crystal violet stain, appearing purple.

Gram-Negative Bacteria

Bacteria with a thin peptidoglycan layer and an outer membrane, appearing pink after counterstaining.

Aerobes

Organisms that require or prefer oxygen for their growth.

Anaerobes

Organisms that cannot survive in the presence of oxygen.

Capsule

A polysaccharide or polypeptide outer layer that aids in adhesion, moisture retention, and virulence.

Fimbriae

Short, hair-like structures that help bacteria attach to host cells or surfaces.

Pili

Longer projections that connect cells and facilitate DNA transfer between bacteria.

Virulence

The ability of a pathogen to overcome host defenses and cause disease.

Biofilms

Structured communities of bacteria embedded in a matrix that increase resistance to antibiotics and the host immune response.

Quorum Sensing

A chemical communication mechanism that allows bacteria to detect their population density and coordinate group behaviors.

Opportunists

Generally harmless organisms that can cause disease under certain conditions when the host's defenses are compromised.