exam 2 - study guide 5 Flashcards
how do phospholipids interact with water
They don’t because water is polar and phospholipid layer is nonpolar
importance of sterols in the membrane
Provide rigidity, permeability, and structural integrity
cell types that contain sterols
common in eukaryotes, not common in prokaryotes
what type of molecule is a sterol
sterols are steroid molecules with a hydroxyl group attached to one of the rings
properties of membranes and mechanisms that substances cross the membrane
they key property is that it is selectively permeable and ions/materials pass through diffusion, osmosis, and active transport
active transport
uses ATP or proton motive forces to move substances
carrier protein moves substance from low to high concentration, against the chemical gradient
passive transport
does not require energy
includes simple diffusion (CO2 and O2), facilitated diffusion (permease carries substance), and osmosis.
functions of proteins
membrane proteins act as selective gate, sensor of environmental conditions, and as a fluid mosaic model.
endocytosis
substance coming into the cell
pinocytosis
small invaginations of cell membrane bring in liquid and liquid-dissolved substances.
phagocytosis
extensions of cell membrane that take up solid material
pmf
Proton motive force. Is harvested to drive cellular processes including ATP synthesis & some forms of transport and motility.
what are extracellular membrane vesicles
membrane-bound vesicles that facilitate communication, cargo transfer, and modify recipient cells functions.
secreted by most cells
proteins, lipids, nucleic acids, and sugars contain EMVs
what are ribosomes, composed of, function
Ribosomes are sites of protein synthesis in cytoplasm.
Composed of protein and rRNA. Small (30S) & large (50S) subunits come together to make a 70S ribosome in procaryotes. Ribosomes facilitate joining of amino acids. Eukaryotes are 80S.
what are chromosomes, composed of, procaryote properties, nucleoid, plasmids
Nuclear material
composed of nucleotides
chromosomes are single, covalently closed, and circular.
Nucleoid is a gel-like region with single circular double-standard DNA and packed tightly via binding proteins & supercoiling.
Plasmids are circular, supercoiled DNA smaller than a chromosome.
what are endospores, common genera of prokaryotes that form these, dipicolinic acid, resistant towards
form when nutrients are depleted in a cell’s environment
Bacillus and Clostridium
dipicolinic acid is a chemical compound that’s part of bacterial spores which aids in heat resistance
resistant to heat, desiccation, chemicals, UV light, and boiling water
How many hours does it take for a vegetative cell to complete sporulation and form a mature endospore (enter dormancy)? How long does it take for an endospore to exit from dormancy and return to vegetative growth
Takes around 8 hours to enter dormancy
minutes to 2 hours to exit dormancy
endospore formations
terminal, subterminal, central
circular or ellipsoid
non-deformed and deformed
How long can endospores remain dormant but remain viable/able to germinate if conditions are favorable?
They can remain viable for potentially hundreds or even millions of years
glycogen granules
storage units for glucose that are made of branched chains of glucose molecules.
polyphosphate granules
intracellular storage structures composed of a linear polymer of phosphate molecules.
polyhydroxyalkanoate granules
storage compartments in bacteria that contain carbon and energy.
extracellular polymeric substances (EPS)
usually polysaccharide sometimes protein secreted by some bacteria outside of cell wall; sometimes includes extracellular DNA. Protects against desiccation &/or chemical stress, nutrient accumulation, allow cell to adhere/stick to surface, protection form phagocytic eucaryotic cells.
biofilm
Polysaccharide-encased community with cell walls & channels that nutrients & wastes pass, cells communicate/coordinate by synthesizing & sensing chemical signals.
capsule
well organized; firmly attached to wall EPS
slime
not well organized; loosely attached to wall EPS
How do properties of a cell in a biofilm differ from the properties of planktonic cells
Biofilm formation begins when planktonic (free-floating) cells move to the surface and adhere.
flagella
specialized appendage attached to the cell body with a rotating filament (protein flagellin)
how many classes of pili are known
6
type iv pili
attach to surfaces, have a twitching motility, secrete/uptake molecules, conjugation
type iii pili
inject virulence proteins into host cell
injectosomes
can deliver effector proteins into eukaryotic cells that can induce changes in host cell cytoskeleton
what is twitching motlity
movement powered by extension and retraction of specializes hair-like structures
fimbriae
attached in large numbers, allowing cell to adhere/stick to surface
adhesion
located on surface of cell that cells to grab other cells
atrichous
no flagella
monotrichous
single flagellum
lophotrichous
tuft of flagella at one end
amphotrichous
single flagellum at each endp
peritrichous
flagella distributed across the entire cell surface
what is taxis, positive differ from negative
the movement of an organism towards or away from a stimulus. positive is towards the stimulus while negative is away
what is chemotaxis, positive differ from negative, phototaxis, aerotaxis, thermotaxis
chemotaxis is movement towards chemicals or nutrients by bacteria
positive is attraction to a chemical while negative is repulsion
phototaxis - response to light
aerotaxis - response to oxygen
thermotaxis - response to temperature
what are the 3 major parts of a domain bacteria prokaryotic flagellum
filament, hook, and basal body
what is flagellin and what makes it
semi-rigid, helical motors than can rotate
filament makes it
flagellar rotation of cell
clockwise rotation - cell tumbles
counterclockwise rotation - propels cell forward in a straight run
how to bacteria cells provide power for flagellar rotation
PMF
Why is the presence of water in a flagellated cell’s surroundings/outside environment important for allowing/facilitating flagellar motility
Water has the relative viscosity to bacteria, give the cell an easy medium to travel through
do fimbriae or pili rotate
NO
neisseria gonorrhoeae - domain, gram, characteristics, releases x during infection, men, women, newborns, treatments
bacteria - rod, spiral, diplococcus
gram negative
fastidious, can be cultured on enriched agar media with elevated CO2, twitching motility
releases lipoligosachharides from OM & peptidoglycan fragments. Causes host defenses to respond, damage host cells, inflammation and pus
men - purlulent discharge from urethra & dysuria
women - infected cervix, typically asymptomatic
urethritis, cervicitis, salpingitis, proctitis, conjunctivitis
newborns - blindness, eye disorders
treat with penicillin, initially effective but many strains are resistant
