Question | Answer |
bacterial cell wall structure is the basis for distinguishing what? | Gram-positive
Gram-negative |
bacteria that are thin, long and coiled | spirochetes |
spirochetes flagella | they have unique flagella for motility
periplasmic flagella (or internal flagella, endoflagella, axial filaments) |
axial filaments cause cell to | causes the cell to move by rotating |
transporters are_________ on cell membrane | selective permeable |
Why is pili produced? | -usually produced when the density of microbes is high is response of sensing |
cork screw motion of motility
swim in a vicous environment | Treponema |
-smaller than flagella, fine, proteinaceous, hairlike-bristles from cell surface
-important for attachment to surface and adhesion during pathogenesis
bind to throat, bladder, etc. to surface
establishes first step of attachement | Fimbriae |
What can resist phagocytosis and be presented from being engulfed by white blood cells? | -encapsulated bacteria |
cell membrane functions | 1. energy generation
-procaryotic cell membrane is the site for electron transport chain during aerobic respiration
2. cell integrity
3. transport |
What forms energy production on the cell membrane? | electron transport chain |
All bacteria have a _____________ | double membrane |
peptidogylcan | peptide (protein) and glycan (sugar)
-a complex molecule composed of glycan chains crossed linked by peptide chains |
What does a peptidoglycan layer look like and why? | chain linked fence because it has wholes and does not block molecule provides mechanical support cell
-strengthen each other with chain and another chain link |
In gram stain, cells either stain _________ (____) or ________ (_____) | purple-gram positive
pink-gram negative |
gram positive bacteria | a thick cell wall composed primarily of peptidoglycan |
gram negative bacteria | have a thin peptidoglycan layer, but have an outer cell membrane |
What are two important components of the cell wall? | lysozyme and penicillin |
-an antibacterial protein secreted by many organisims
-it hydrolyzes the glycan chain
-like bacteria cells
-cuts glycan chain | lysozyme |
-antibiotic
-inhibits the formation of peptide crosslink in dividing cells
-causes cell to targets and different part of glycan either way when treated with 2 agents will be killed | penicillin |
procaryotes external structure | flagella, pili, fimbriae |
return to vegetative growth from spore form; triggered by nutrients | germination |
-a process that results in the formation of endospores
-can be caused by nutrient depletion | sporulation |
cell envelope | -glycocalyx (capsule, slime), cell wall, cell membrane |
procaryotes internal structure | chromosome (nucleiod) ribosome, inclusion bodies |
What does a cell do? | 1. Growth and Development
2. Reproductive and heredity
3. Metabolism
4. Movement and/or irritability
5. Cell support
6. transport of nutrients |
Reproduction and heredity | genetic materials, reproduce offspring sexually or asexually |
metabolism | -chemical and physical life processes |
movement and or irritability | -respond to internal/external stimuli |
cell support, protection and storage mechanisms | -cell walls
-vacuoles
-granules
-inclusions
-transport of nutrients and waste |
Flagellum/Flagella | 1.filament
2.hook
3.basal body
-rotates 360° in response to signals
-1-2 or many distributed over entire cell
-functions in motility |
curved sheath | hook of flagella |
stack of rings firmly anchored in cell wall and membrane | basal body of flagella |
long thin helical structure composed of proteins | filament of flagella |
small bunches ariving from one end of cell | lophotrichous |
single flagellum at one end | monotrichous |
flagella at both ends of cell | amphitrichous |
flagella dispersed over surface of cell | peritrichous |
Which is most motile flagella arrangement? | peritrichous |
________function to guide bacteria in a direction in response to external stimuli | flagella |
bacteria movement in response to chemical signals | chemotaxis |
movement toward or away from light | phototaxis |
flagella location and reason | -between 2 membranes so when it turns can cause bacteria cell to move distinctly from flagella outside of cell |
spirochetes flagella location | -between the inner and outer membrane |
[spirochetes flagella] function in motility | -twisting and corkscrew |
syphilis | -spiral bacteria
-sexually transmites
-initiates intake of bacteria |
pili | -rigid tubular structure made of pili protein subunits
-Function:
1.joins two bacterial cells, enable DNA transfer, from one cell to another ("conjuction")
2. adhesion |
glycocalyx | -coating of molecules external to the cell wall, made of sugars (main compartment) and or proteins |
capsule | one type of glycocalyx
highly organized, tightly attached |
slime layer | -loosely organized and attached
-one type of glycocalyx
-allows bacteria to attach
-bad causes tissue/heart damage |
capsule function | -encapsulated cells exhibit smooth morpholgy (smooth vs. rough)
Function: protects bacteria from being destroyed by host phagocytes (white blood cells)
-capsule is associated with pathogenic bacteria |
slime layer function | enable attachment and aggregation of bacterial cells on solid surface
-involved in biofilm formation |
Cell Membrane | -bacterial cytoplasmic membrane composed of phospholipids bilayer embedded proteins |
eukaryotic energy is produced where? | -on mitochondria |
cell wall | 1. located directly outside the cell membrane because membrane can burst
2. bacterial cell wall contains the macromolecule peptidoglycan
3. function: mechanical support of the cells |
cell wall function | mechanical support of cells: maintain shape, keep bacteria from bursting due to changes in osmotic pressure |
peptide crosslink is between two M sugars | G: NAG
M: NAM |
not found in protein but in cell wall | D-glutamate |
What is the result of lysozyme or penicillin treatment? | cell burst
lysozyme cuts between sugars
penicillins prevent crosslinks from forming |
endospore formation and types | -formed with in the cell
-produced by some G+ genera:
Clostridium, Bacillus and Sporosacrcina |
What type of cells are endospores?
How are they developed? | -they are resting, dormant cells
-developed from vegetative cells when conditions become nonfavorable |
Why is it said that endospores are the "hardiest of all life forms"? | 1. withstand extremes in heat, drying, freezing, radiation and chemicals
2. longevity verges on immortality (25-250 million years)
3. resistant to ordinary cleaning methods and boiling
4. Sterilization methods usually kill spores |
What specifically will kill endospores? | -pressurized steam at 120°C for 20 to 30 minutes will destroy this |
endospores contain high levels of ______ and ____________ | -calcium
-dipicolinic acid
(mutent of cell no longer produce this chemical)
important for heat resistance |
the core of endospores are ___________ | dehydrated
important for heat resistanceEn |
Endospores have a thick ____________ | thick protein coat
important for chemical resistance |
Endospores are ___________ inactive
>important for _____________ | -metabolically
-radiation resistance |
Spore-forming bacteria have a _______ life cycle: 1._______ and 2.________ | 2 phase life cycle
1. vegeatative cell
2. endospore form |
vegetative form | -actively growing
-metabolizing, or
-producing toxins in some pathogenic species (such as B. anthracis, C. tetanus)
-found in food tissues |
What is vegatative form sensitive to? | chemicals, heat, drying and antibiotics |
spore-form | resistant form often found in soil or air |
endospore causes disease the vegetative part causes what? | -tissue damage |
-contains crystals of magnets
-highly organized species granules
-makes them into magnetic field to find optimum oxygen environment | magnetisome |
it grows when stressed out about oxygen
-whether granuole formation it is more resisten to other factors
-found in GI tract | Bifidobacterium |
usually energy reserve and enviromental resistant as well (I think?)
-volutions, poly P
in Corymobacterium | metachromatic granules |
-function in cell wall maintenance and enlargement during cell division; move cations across the cell envelope; stimulate a specific immune(or host) response | teichoic acid lipoteichoic acid |
composed of an outer membrane and a thin-layer of peptidoglycan
-has a periplasmic space | Gram negative cell wall |
-enable a cell to store nutrients, and to survive nutrient depleted and other stress conditions | What are granules other name and what is their function
-inculusion bodies |
Gram positive cell wall | -thick peptidoglycan (PG) layer
-acidic polysaccharides teichoic acid and lipoteichoic acid |
lipid moleules inner/outer leaflet | inner leaflet: phospholipid; outer leaflet: lipopolysaccharide (LPJ) |
let certain molecules (<600 dalton) enter and leave cell, to compensate for the OM barrier effect | Has porins |
makes G-bacteria more impermeable to disinfectants dyes and certain drugs than G+ | OM(outer membrane) makes what? |
-can be released during cell lysis
-is often proinflammatory and cause damages to the infected host
-therefore LPS is also called enodtoxin (as opposed to exotoxin) | lipopolysaccharide (LPS) |
lipopolysaccharide (LPS) explain | part hidden in lipid but when will it be exposed driving blood infections which can cause endotoxic shock |
Gram stain steps | 1.make smear and apply crystal violet (primary dye)
2. add Gram's iodine (mordant)-functions as intensified binding
3. alcohol-can't be removed because of tight bond from mordant
(decolorizes)
4. add safranin (red dye counterstain) pink |
Quick summary of gram stain steps | 1. primary stain (crystal violet)
2. mordant (iodine)
3. decolarization (alcohol)
4. counterstain (safranin)
G+:purple G-:pink |
function of ribosomes | -site of protein synthesis |
List 3 types of bacteria with unique cell wall structure and properties | 1. Acid-fast bacteria
2. L-forms
3. Mycoplasmas |
myobacterium apperance | -waxy because in cell wall also have a waxy layer |
mycolic acid (1) | -unique lipids (<-? look up)
-the cells stain gram positive, but sometimes give beaded appearance
-in acid-fast stain, the waxy cell wall enables the cell to retain the carbolfuchsin dye even after stained by acid alcohol |
mycolic acid (2) | -cell wall lipids contribute to high degree of resistance to many dyes, disinfectants, and drugs |
chromosome | -usually a single DNA molecule tightly coiled and aggregated in a dense area called nucleoid
-DNAs in bacteria and archaea are usually circular dobule stranded DNA
-chromosomal DNA contains all essential genetic information for the cell |
bacteria that have lost the cell walls due to drug treatment (and surviving!) | L-forms |
_____can cause some bacteria to develop alternative mechanisms for support. Those ____ are called_______. | -mutations
-mutants
-L-forms |
-bacteria naturally lack a peptidoglycan cell wall
-live closely with host cells
-during evolution they have lost a lot of capabilities, including PG synthesis
-cell membrane contain sterols, for stability | mycoplasma |
-don't have cell wall have very irregular shapes
-take cholesteroal from our cells and strengthen them
-to survive in cell called mycoplasma | mycoplasm (again notes) |
Know difference between mycobacterium and mycoplasma | mycoplasm-no cell wall cell bacteria from with out all cell wall
transport sexually transmitted disease
mycobacterium-acid-fast |
gelatinous solution containing water, nutrients, proteins and genetic material
-(soup-inside of cells)
-insdie cell ribosomes unique gradually genetic material | cytoplasm |
DNA (full name and what it includes) What are the genetic material? | -deoxyribonucleic acid (DNA)
-chromosome and plasmidss: the genetic materials |
surrounds the thylakoids | stroma |
how many ribosomes are in eucaryotic organisms | 80S ribosomes |
eucaryotics are composed of what | ribosome protein and rRNA |
eucaryotics are assembled from the ______ and ______ subunits | 40S and 60S |
how different is eucaryotes from procaryotes | different from 70S ribosomes of procaryotes |
eucaryotes present where? | cytoplasm and RER |
granules can be | organic or inorganic |
hydroxyl buturate | -for colony hydroxyl something
-when access nutrient available can be used when nutrient is needed |
glycogen | -polymers of glucose organisms usually makes them into polymers |
inclusion bodies | -granules
-often contain polymers, examples:
1.glycogen
2.polyhydroxlbutyrate (PHB)
3.gas vesicles
4.polyphosphate granules (also called poly P, metachromatic granules or volutin granules) |
Ribosome apperance | 2 subunits
-large subunit (50S)
-small subunit (30S)
together make (70S) and form tight molded shape that is strong |
ribosomes | -super structures containg 3-4 long molecules
-ribosomal RNA (rRNA): 60%
-ribosomal proteins: 40% |
plasmids application | used in genetic engineering rendily manipulated and transferred from cell to cell |
plasmids replication | duplicated and passed on to offspring during cell division, independent of chromosome replication |
genetic structures | DNA, RNA |
mycobacterium | genus have several pathogens including ones causing TB and leprosy
acid-fast bacteria |
Gram stain beaded skin dyes | can't penetrate very well |
Acid fast stain name two | 1. M. tuberculosis
2. M. leprae
M.=Mycobacterium |
acid-fast stain is a diagnostic tool for what? | 1. tuberculosis (mycobacterium tuberculosis)
2. leprosy (M. leprae) |
What does Gram stain tell us? | -shape of cell
-whether gram is positive or negative |
-Important basis of bacterial classification and identification
-practical aid in diagnosing infection and guiding drag treatment | Gram stain importance and practicalness |
Gram-negative | -lose crystal violet and stain red form safranin counterstain |
Gram-positive | -retain the crystal violet dye and stain purple |
The thickness of what is important from a gram stain | PG (peptidoglycan)
1. Gram-positive
2. Gram-negative |
Gram stain | -differential stain that distinguishes cell with a Gram-positive cell wall from those with a Gram-negative cell wall |
outer membrane (OM) in gram negative bacteria | more info to come |
lipopolysacchrid | 3 components:
-list here: |
try to understand the process of lactose | -not fermented by all organisms the lack of enzyme is reponsible inability to ferment lactose organisms in a way |
size of Ribosomes | 70S consists of 2 subunits large (50S) and small (30S)
-procaryotic ribosomes are different from eucaryotic ribosomes in size and number of proteins (70S vs. 80S) |
What cells have ribosomes? | all |
plasmids genetic information encoded by plasmids | -not essential to bacterial growth and metabolism
-may encode antibiotic resistance tolerance to toxic metals enzymes and toxins that allow the cells to survive better
important for the spread of drug resistance |
-smaller, circular double-stranded DNA
-free or integrated info the chromosome
-copyy number can vary from 1-500 | plasmids |
What do procaryotic cells have instead of a nucleus | chromosomes |
RNA | Ribonucleic acid
Ribosome RNA (rRNA)
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomes: protein synthesis |