Day 6: Microorganisms and Bacterial Structures

These flashcards cover key terms and definitions related to microorganisms, particularly focusing on bacterial structures and their functions.

Pleomorphism

Variations in cell wall structure caused by slight genetic or nutritional differences

Prokaryotic cells

Cells that lack a nucleus and other membrane-bound organelles, typically smaller than eukaryotic cells.

Gram-positive bacteria

Bacteria that have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain during Gram staining.

Gram-negative bacteria

Bacteria that have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides, do not retain the crystal violet stain.

Peptidoglycan

A structural component of bacterial cell walls, consisting of glycan chains cross-linked by peptide fragments.

Coccus

Spherical-shaped bacteria.

Bacillus

Rod-shaped bacteria.

Vibrio

Bacteria that are comma-shaped or gently curved rods.

Spirochete

A flexible, spiral-shaped bacterium that exhibits twisting movements.

Fimbriae

Thin, hair-like structures on the surface of bacteria that allow for adherence to surfaces.

Flagella

Long, whip-like structures that aid in bacterial movement.

Endospores

Dormant, tough structures formed by some bacteria to survive extreme environmental conditions.

Biofilm

A complex aggregation of microbes adhering to surfaces, organized in a protective community.

Chemotaxis

The movement of an organism in response to a chemical stimulus.

Cytoplasm

The gel-like substance within a cell, containing organelles, enzymes, and nutrients.

Ribosome

Molecular machines in cells that synthesize proteins from amino acids.

Plasmid

Extrachromosomal DNA that can carry genes of antibiotic resistance and virulence in bacteria.

Nanotubes

Thin extensions of the cytoplasmic membrane that facilitate intercellular communication and electron transfer.

Acid-fast bacteria

A type of bacteria, such as Mycobacterium, that do not take up Gram stain due to mycolic acid in their cell walls.

Mycoplasma

Bacteria that naturally lack a cell wall and are often resistant to antibiotics targeting cell wall synthesis.

Archaea

Single-celled organisms similar to bacteria but with distinct biochemistry and genetics, often found in extreme environments.

Eukaryotes

Organisms whose cells contain a nucleus and other organelles enclosed within membranes.