Micro Exam 1 Test Questions – Flashcards
Unlock all answers in this set
Unlock answersTransmembrane protein Integral protein Peripheral protein |
t: protein that spans the entire biological membrane; type of intergral protein i: protein that is permanently attached to the biological membrane p: temporarily adhere to the biological membrane; attach to integral |
Nicholson-Singer fluid mosaic membrane model |
membrane/proteins are capable of lateral motion some proteins embedded in membrane in prokaryotic or eukaryotic still considered most viable model of membrane since 1972 |
2 structures for membrane stabilization |
1. Sterol- planar molecule, eukaryotic, cholesterol 2. hopanoid- 5 rings structure, prokaryotic, diploptene hopanoid |
Membrane functions (6) |
1. Semipermeable barrier 2. Regulation (metabolite uptake, waste release) 3. Redox reactions (electron transport systems) 4. Coordination of binary fission and sporulation (septum formation) 5. Synthetic reactions 6. Chemotaxis/sensing apparati |
3 types of synthetic reactions |
- lipids - peptidoglycan - secretory proteins |
How do molecules pass through a biological membrane? |
Phagocytosis Endocytosis Exocytosis |
Passive diffusion vs. facilitated transport |
p: water/co2 can simply diffuse high to low through membrane f: need transport or carrier protein when available |
Other terms for facilitated diffusion |
Transporters Permeases Facilitators Carriers |
Sources of energy in a cell |
ATP- adenosine triphosphate PMF- proton motive force (electrochemical gradient) |
2 types of transporters |
MFS- major facilitator superfamily IDS- ion dependent transport system ** depend on concentration gradient** |
Cotransport systems (3) |
Utilize energy of PMF 1. Symport- same way down channel, prokaryotic sugars/ eukaryotes 2. Antiport- one in, one expelled 3. Uniport- one one material down channel |
Efflux system |
part of antiport expulsion of antibiotic or waste |
ABC transport system |
ATP binding cassette 3 regions: 1. Solute binding protein (SBP)- attaches to appropriate protein and brings to mouth of channel (g+ can diffuse away, g- close because of periplasm) 2. Membrane spanning domain (MSD)- 2 barrel channel through protein, 12 alpha helices lining 3. Nucleotide binding domain (NBD)- binding of ATP |
Group translocation system |
Prokaryotes only chemically alters substrate 12 alpha helices in transmembrane protein phosphorylation energy from PEP |
Do prokaryotes or eukaryotes have more proteins? |
Prokaryotic - 800 Eukaryotic- 225 |
Bactoprenol |
transports NAM and NAG across the cell membrane in the synthesis of peptidoglycan |
Secretory systems (4) |
Translocase (expulsion) Sec system Type III (injectisome) Signal sequence |
Sec system |
- secA translocase- secretion and insertion of proteins in the cell membrane - leader sequence of 15-20 amino acids |
Type III secretion system |
- AKA: injectisome - in gram negative bacteria - produce a toxin that inserts into eukaryotic cell |
Characteristic structures when the cell membrane invaginates |
- still continuous with cell membrane - see by electron microscopy - structures: tubes, vesicles, bundled tubes, stacks, lamellae |
Another name for glycocalyx |
EPS- extracellular polymeric substance |
Types of glycocalyces |
1. capsule- distinct gelatinous layer for protection/attachment 2. slime layer- diffuse and irregular layer for protection/attachment |
Visualization of glycocalyx |
external to cell wall do not stain well - negative/background stain (stain everything were not interested in) - india ink |
3 bacteria causing pneumonia |
Klebsiella pneumoniae Streptococcus pneumoniae Mycoplasma pneumoniae |
Glycocalyx colonies (2) |
1. smooth- AKA mucoid, mucous/stringy 2. rough- little extracellular matrix material |
Chemical composition of glycocalyx |
primarily sugar polymers (polysaccharides) few amino acids (polypeptides) |
What makes up polysaccharides? |
glucans and dextrans (glucose) |
What genus gives a proteinacious glycocalyx? |
Bacillus spp. |
Glycocalyx functions (6) |
1. Adhesions/adherence 2. Protection against dessiccation 3. Protect against bacteriophage infecton and noxious chemicals 4. Carbohydrate reserve (?) 5. Protection against elimination by phagocytosis (virulence mechanism) 6. Classification and type specific markers for Streptococcus pneumoniae |
Biofilm (definition and 3 examples) |
polysaccharide encased mass of bacteria coating a surface - can only cause disease if encapsulated ex) Streptococcus mutans - dental plaque Streptococcus pneumoniae - low bar pneumonia (elderly) Haemophilis influenzae- infections in children (ear) |
Classification by type specific markers |
K or Vi antigens |
Dental caries |
dental plaque Streptococcus mutans most common infectious disease due to excess sucrose attaches to teeth, anaerobic environment, sugar ferments, acid prodcued, tooth erosion |
Types of pili/fimbriae |
1. Conjugal, fertility, sexual- has to do with genes (uncommon) 2. Somatic/body- designated by type and function |
CFA & PAK |
CFA: colonization factor antigen in E. coli PAK: causes thrush |
Functions of pili |
1. gene transfer (conjugation) 2. Anti-phagocytic 3. Adherence |
Adherence mechanisms among prokaryotes (2) |
Afimbrial: due to glycoclayx, adhesins embedded Fimbrial: due to fimbriae/pili, adhesins at end of pilus with O markers |
E. coli fimbrial systems (5) |
1. ETEC- enterotoxinogenic ecoli- binds to enterocytes in intestinal epithelium 2. EIEC- enteroinvasive ecoli 3. EAEC- enteroaggregative ecoli 4. EPEC- enteropathogenic ecoli 5. EHEC- enterohemorrhagic ecoli (O157) |
Fimbrial system bacteria (3) |
Klebsiella pneumoiae Pseudomonas aeruginosa (cystic fibrosis) Candida albicans (eukaryotes, fungus, PAK) |
Tropism (definition and 2 examples) |
act on cell with appropriate receptor Streptococcus pyogenes - receptors in back of the throat Bordetella pertusis- whooping cough, receptors in respiratory tract |
Flagella shapes (5) |
1. Monotrichous: polar, single flagella on one side 2. Amphitrichous- 2 to 4 flagella on both sides 3. Lophotrichous- many flagella on one side 4. Peritrichous- flagella all around, evenly distributed 5. Atritrichous- no flagella, still motile |
Sinusoidal shape of flagella |
same wavelength and amplitude rigid helical |
Pilin |
protein subunits of pili that are unique in every pilus |
3 components of flagella |
Basal body/granule Hook Filament |
Basal body/granule (definition & g+/g-) |
- tube with several sets of rings attached in every bacterial cell w/ flagella - anchors flagellum to cell wall/membrane g-: 2 sets of rings, top & by stator, perimplasmic space g+: one set of rings around stator |
Stator |
part of basal body/granule where motion is generated from PMF rapid rotation embedded in cell membrane |
Hook |
-part of flagella that swings out due to centrifugal force -amino acids/proteins -connects filament to cell surface |
Circumferential slip |
push or pull bacteria from aqueous environment - due to rotation from basal body - drill bit |
Filament |
rigid rotates extends into exterior environment majority of flagella (stringy) |
3 ways to identify flagella |
1. leifsons flagellar stain: salt along flagella visible with light microscopy 2. wet mounts- see organism as it moves through aqueous environment 3. motility detection medium |
Spirochetal Ultrastructure |
type of flagella in spirochetes spirillum morphology AKA: endoflagella & axial fibrils |
Inside spirochetal ultrastructure |
1. peptidoglycan: patches, flexible 2. axial filaments: folded inside cell 3. protoplasmic cylinder: cell membrane, peptidoglycan, outer sheath |
Where is flagella in spirochetal ultrastructure? How does it move? |
- inside (endoflagella) - pairs that overlap - moves by internal rotation- entire body rotates |
Spirochetosis baceria |
Treponema spp. (treponematosis) Leptospira spp. Boriella spp. |
Treponema bacteria (4) |
Treponema pallidum- syphillis Treponema microdentia Treponema denticole Treponema vincentii- ANUG: acute necrotizing ulcerative gingivitis |
Leptospira spp. is from what and causes what disease? |
from contaminated waters causes weils disease |
Lymes disease bacteria |
Borrelia burgdorferi |
Nucleoid characteristics (7) |
1. Chromatin material 2. Electron opaque region by EM 3. Covalently closed double stranded circular DNA 4. Haploid 5. Multiple identical copies 6. Associated with cell membrane 7. Can be stained and seen by light microscopy |
mbp in nucleoid compared to eukaryotic cell |
mbp: million base pairs nucleoid = 4.5 eukaryotic = 40 to 50 |
Supercoiled DNA |
- compactness - replication requires breaking one strand - need enzymes: topoisomerase II/DNA gyrase to wind, topoisomeras IV to unwind - unique to prokaryotes - ex) E. coli is 2-3 nm big, but 1 mm of DNA fits |
Plasmid functions (3) |
1. extrachromosomal DNA (outside chromosome) 2. Non- essential genes 3. Replication |
Episomes |
can jump into chromosomes considered to be extrachromosomal DNA |
Non-essential genes |
- gives advantages in environment - pathogenicity islands- clustered together to form virulence mechanism ex) having an extracellular matrix |
2 types of replication in plasmids |
Relaxed: have necessary information to replicate itself Stringent: replicated with bacterial chromosome present |
Types of plasmids (3) |
1. Engineered genes for genetic engineering workbench 2. Virulence plasmids for pathogenicity islands 3. R (resistance) factors- genes that inactivate antibiotics |
R plasmids |
- R factors (whole plasmid) can be transferred to other bacteria - Self transmissable (itself) vs. mobilizable (help) - R factors are not limited to antimicrobials - All linked, 6-12 antibiotic resistance |
RTF |
resistance transfer factor - genes necessary for replication - conjugation - resistance to antibiotics - resistance to elements: antimony, arsenic, mercury, lead |
Ribosomal function |
protein synthesis joining of amino acids |
Ribosome ultrastructure |
70S: prokaryotic, 30S + 50S 80S: eukaryotic - differences are targets of antibiotics - higher number = faster to settle, higher density - highly conserved rRNA and protein - significance in medicine |
Endospore details (4) |
1. produced by specific genera: bacillus spp. & clostridium spp. 2. Resistance structure: no reproductive value, resistant to extremes 3. Produced under threatening environmental conditions and complex developmental program 4. Long state of dormancy |
Bacillus & Clostridium spp. examples (4) |
Bacillus anthracis Clostridium botulinum- food exotoxin Clostridium tetani- tetanus Clostridium perfringens - gas gangrene |
Sporulation and germination |
s: formation of endospore, low C/N amount g: exit dormant stage and create vegetative cell by cortex cracking |
Identification of endospores (5) |
1. Position 2. Size 3. Shape: central/metacentric, subterminal, terminal 4. Laminated appearence 5. Unique chemical compostion |
Endospore stain and common location |
stain: schaefer-fulton location: soil |
Gonnorhea bacteria |
Neisseria gonorrhoeae |