Chapter 3: Prokaryotic Profile Flashcards
How to distinguish prokaryotes from eukaryotes
the way their DNA is packaged (lack of nucleus)-circular DNA, the plasmid and the thread-like chromosome; the makeup of their cell wall (peptidoglycan and other unique chemicals); their internal structure (lack of membrane-bounded organelles)
All bacterial cells possess…
a cell membrane cytoplasm ribosomes a cytoskeleton one (or a few) chromosome(s)
Some bacterial cells possess…
flagella, pili, and fimbriae an outer membrane plasmids inclusions endospores intracellular membranes
Average size of prokaryotic cells
1 um
Pleomorphism
Cells of one species may vary in shape and size; caused by variations in cell wall structure
Cocci
spheres
Diplococci
two spheres
Streptococci
chain of spheres
Tetrad
4 coccis in a square
Sarcina
cubic configuration of 8 cocci
Staphylococci
grape-like clusters of cocci
Name this bacterial shape
Coccus
Name this bacterial shape
Coccobacillus
Name this bacterial shape
Vibrio (gently curved)
Name this bacterial shape
Bacillus
Name this bacterial shape
Spirillum
Name this bacterial shape
Spirochete
Three parts of a flagella
Filament; Hook; Basal Body
Flagellin
the protein that composes the filament of the flagella
Pilli
Projection that helps bacteria to fasten onto surfaces such as host membranes.
Monotrichous
Single flagella
Lophotrichous
small bunches or tufts of flagella
Amphitrichous
Flagella at both poles of the cell
Peritrichous
flagella dispersed randomly over the cell
Chemotaxis
Chemical signals that trigger bacterial movement
Runs (movement)
smooth linear movement towards a stimulus
Tumbles (movement)
flagellar rotation reverses, causing cell to stop and change its course
Fimbriae
short, thin, hairlike, proteinaceous appendages up to 1,000/cell; mediate attachment to surfaces
Capsule
Outer layer of cell usually composed of polysaccharides; well organized and not easily removed from cell
Slime Layer
similar to capsules except diffuse, unorganized and easily removed