Chapter 3 Flashcards
coccus bacteria shape
spherical or ball-shaped
bacillus bacteria shape
rod, cylindrical
vibrio bacteria shape
rods that are gently curved
spirillum bacteria shape
slightly curled or spiral-shaped body (rigid helix)
spirochete bacteria shape
corkscrew-shaped; spiral cell, more flexible (resembles a spring)
filaments bacteria shape
produce multiple branches off of a basic rod
what are staphylococci (micrococci)?
irregular clusters of cocci cells
what are streptococci?
chains of cocci
what are sarcina?
cubical packet of eight, sixteen, or more cocci cells
what are streptobacilli?
chain of several bacilli
what are palisades?
bacilli cells of a chain remain partially attached by a small hinge region at the ends
spirilla definition
occasionally found in short chains
spirochetes definition
rarely remain attached after cell division
Monotrichous flagella
single flagellum
Lophotrichous flagella
small bunches or tufts of flagella emerging from the same site
Amphitrichous flagella
flagella at both poles of the cell
Petrichous flagella arrangement
flagella are dispersed randomly over the surface of the cell
What are the 2 types of chemotaxis (explain each)
positive chemotaxis: movement toward a favorable chemical stimulus
negative chemotaxis: movement away from a repellant
role of fimbriae
- bristle-like fibers sprouting off the surface of many bacterial cells
- allow tight adhesion between fimbriae and epithelial cells, allowing bacteria to colonize and infect host tissues
role of pili
-used in conjugation between bacterial cells (partial DNA transfer from one cell to another)
what can Type IV pilus do?
it can transfer genetic material, act like fimbriae and assist in attachment, and act like flagella and make a bacterium motile
what are nanotubes (nanowires)?
- thin, long, tubular extensions of the cytoplasmic membrane
- used as channels to transfer amino acids or to harvest energy by shuttling electrons to iron-rich substances
what is the S layer in bacteria?
single layers of thousands of copies of a single protein linked together like tiny chain link fences (armour)
- only produced when bacteria are in a hostile environemnet
what is glycocalyx role in bacteria?
coating of repeating polysaccharide or glycoprotein units
what are the types of glycocalyx layer
slime layer: loose, protects against loss of water and nutrients
capsule: more tightly bound, denser, and thicker; produce a sticky (mucoid) character to colonies on agar
2 types of flagellar movement
run: rotation fo flagellum counterclockwise, resulting in a smooth linear direction
tumble: reversal of the direction of the flagellum, causing the cell to stop and change course (clockwise)
3 layers of the cell envelope
cell wall
cytoplasmic (cell) membrane
outer membrane
What are Mycoplasmas
bacteria that naturally lack a cell wall; have sterols in the cell membrane that stabilize the cell against lysis
What are L forms
bacteria that naturally have cell walls but lose it during part of their life cycle
What disease does Bacillus anthracis cause?
anthrax
What disease does Clostridium tetani cause?
tetanus
What disease does Clostridium perfringens cause?
gas gangrene
What disease does Clostridium botulinum cause?
botulism
What disease does Clostridioides difficile cause?
a serious gastrointestinal disease
