Module 2 Test Flashcards
Chapters 4, 5, and 6
Basic cell shapes
Spherical, cubical, cylindrical
Internal contents of cells
Cytoplasm surrounded by a membrane
Eukaryotic cells
Includes animals, plants, fungi, and protists
-Membrane-bound organelles
-Double membrane bound nucleus
Prokaryotic cells
Includes bacteria and archaea
-No nucleus or membrane bound organelles
-Smaller and less complex
Characteristics of life
-Reproduction and heredity
-Growth and development
-Metabolism
-Movement and/or irritability
-Cell support, protection, and storage
-Transport of nutrients and waste
Prokaryotes: Appendages for motility
Flagella and axial filament (periplasmic flagella)
Prokaryotes: Appendages for attachment or channels
Fimbrae and pili
What composes a flagella?
Filament- long, thin, helical structure composed of flagellin
Hook- curved sheath
Basal body- stack of rings firmly anchored in cell wall
Monotrichous flagella
single flagellum at end
Lophotrichous flagella
Small bunches emerging from the same site
Amphitricous flagella
Rare flagella at both ends of cell
Peritrichous flagella
flagella dispersed all over surface of cellP
Phototaxis
light stimuli
Chemotaxis
Chemical stimuli
+ vs - taxis
+=toward/attracted to
-= away/deterred from
Motion in flagella
Counterclockwise- run
Clockwise- tumble
Periplasmic flagella
-Internal flagella enclosed in the space between the outer sheath and cell wall (peptidoglycan)
How do periplasmic flagella produce motility?
By contracting and imparting twisting or flexing motions
Prokaryotes: Fimbriae
Fine, proteinaceous, hairlike bristles emerging from cell surface
Fimbriae Function
Function in adhesion to other cells and surfaces
Prokaryotes: Pili
Rigid, tubular structure made of pilin
Gram-negative cells only
Function of pili
Function to join cells for partial DNA transfer
Conjugation
DNA transfer– send genetic material via channel
Prokaryotes: Glycocalyx
Coating of molecules external to cell wall made of sugars and/or proteins