Unit 1 Ch 2 - Microbial Cell Structure and Function Flashcards
from Unit 1 -The Foundations of Microbiology
Archaellum
a long, thin cellular appendage present in many Archaea that rotates and is responsible for swimming motility
Basal body
the ‘motor’ portion of the bacterial flagellum, embedded in the cytoplasmic membrane and cell wall
Capsule
a polysaccharide or protein outmost layer, usually rather slimy, present on some bacteria
Chemotaxis
directed movement of an organism toward (positive chemotaxis) or away from (negative chemotaxis) a chemical gradient
Chloroplast
the photosynthetic organelle of phototrophic eukaryotes
Cristae
the internal membranes of a mitochondrion
Cytoplasmic membrane
the permeability barrier of the cell, separating the cytoplasm from the environment
Cytoskeleton
the cellular scaffolding typical of eukaryotic cells in which microtubules, microfilaments and intermediate filaments define the cell’s shape
Dipicolinic acid
a substance unique to endospores that confers heat resistance on these structures
Endospore
a highly heat-resistant, thick-walled, differentiated structure produced by certain gram-positive Bacteria
Flagellum
a long, thin cellular appendage that rotates (in Bacteria) or has a whiplike motion (in Eukarya) that is responsible for swimming motility
Gas vesicles
gas-filled cytoplasmic structures bounded by protein and conferring buoyancy on cells
Histones
highly basic proteins that compact and wind DNA in the nucleus of eukaryotic
Hydrogenosome
an organelle of endosymbiotic origin present in certain microbial eukaryotes that oxidizes pyruvate to H2, CO2 and acetate, and couples this to ATP synthesis
Intermediate filament
a filamentous polymer of fibrous keratin proteins, supercoiled into thicker fibers, that functions in maintaining cell shape and the positioning of certain organelles in the eukaryotic cell
Lipopolysaccharide (LPS)
a combination of lipid with polysaccharide and protein that forms the major portion of the outer membrane in gram-negative Bacteria
Lysosome
an organelle containing digestive enzymes for hydrolysis of proteins, fats and polysaccharides
Magnetosome
a particle of magnetite (Fe3O4) enclosed by a nonunit membrane in the cytoplasm of magnetotactic Bacteria
Meiosis
the nuclear division that halves the diploid number of chromosomes to the haploid
Microfilament
a filamentous polymer of the protein actin that helps maintain the shape of a eukaryotic cell
Microtubule
a filamentous polymer of the proteins (alpha)-tubulin and (beta)-tubulin that functions in eukaryotic cell shape and motility
Mitochondrion
the respiratory organelle of eukaryotic organisms
Mitosis
nuclear division in eukaryotic cells in which chromosomes are replicated and partitioned into two daughter cells during cell division
Morphology
the shape of a cell - rod, coccus, spirillum and so on
Nucleus
the organelle that contains the eukaryotic cell’s chromosomes
Outer membrane
a phospholipid- and polysaccharide-containing unit membrane that lies external to the peptidoglycan layer in cells of gram-negative Bacteria
Peptidoglycan
a polysaccharide composed of alternating repeats of N-acetylglucosamine and N-acetylmuramic acid arranged in adjacent layers and cross-linked by short peptides
Periplasm
a gel-like region between the outer surface of the cytoplasmic membrane and the inner surface of the lipopolysaccharide layer of gram-negative Bacteria
Peritrichous flagellation
having flagella located in many places around the surface of the cell
Phototaxis
movement of an organism toward light
Pili
thin, filamentous structures that extend from the surface of a cell and depending on type, facilitate cell attachment, genetic exchange or twitching motility
Polar flagellation
having flagella emanating from one or both poles of the cell
Poly-(beta)-hydroxybutyric (PHB)
a common storage material of prokaryotic cells consisting of a polymer of (beta)hydroxybutyrate or another (beta)-alkanoic acid or mixtures of (beta)-alkanoic acids
S-layer
an outermost cell surface layer composed of protein or glycoprotein present on some Bacteria and Archaea
Stroma
the lumen of the chloroplast, surrounded by the inner membrane
Teichoic acid
a phosphorylated polyalcohol found in the cell wall of some gram-positive Bacteria
Thylakoid
a membrane layer containing the photosynthetic pigments in chloroplasts
