Micro Chapter 4 Answers – Flashcards
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Unlock answersProkaryotes (Pre Nucleus) -Bacteria & Archaea |
-DNA NOT enclosed within membraine -Singular circular arrangment -DNA is NOT associated w/Histones-has other proteins -LACK membrane enclosed organelles -Cell walls: PEPTIDOGLYCAN -BINARY FISSION reproduction -Very small: 1-10 microns -Psuedomurein cell walls in ARCHAEA |
Eukaryote -fungi, protista, animalia, plantae |
-DNA in NUCLEUS, NUCLEAR membrane -DNA associated w/HISTONES & nonhistones -MEMbrane enclosed organelles: mitochondria, ER, golgi, lysosome, some chloroplasts -Polysachharide cell walls if present -MITOTIC spindle reprod.= MITOSIS -Very big: 10-1000 microns |
| Bacteria shapes |
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Cocci Arrangments Diplococci: Streptococci: Tetrads: Sarcinae: Staphylococci: |
-cocci that remain in pairs -divide & remain attatched in chainlike -divide in 2 planes & remain in groups of 4 -divide in 3 planes & cubelike grps of 8 -grape like clusters
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Bacilli Arrangments appear as single rods, long twisted chains less grouping then cocci 1) Diplobaccili 2)Streptobacili 3)Coccobacilli
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1) appear in pairs 2) CHAINS 3)oval and look just like cocci |
SPiral -have one or more twists, never straight 1) Vibrios 2) Spirilla 3) spirochetes |
1) curved rods 2) helical shape- use FLAGELLA to move 3) helical & flexible- use AXIAL FILAMENTS to move |
MONOMORPHIC Pleomorphic |
Bacteria is determined by heredity = maintain a single shape = can have many shapes |
| Bacteria size |
- usually .2-1.0 microns x 2.8 microns?
text says .2-2.0 microns in diamter 2-8 microns in length |
Glycocalyx (sugar coat) (prokaryotes secrete this on their surface) Capsule: if the substance is organized and FIRMILY attatched to cell wall. Can be determined by NEGATIVE STAINING |
-OUtside cell wall -STICKY -Capsule: neatly organized -SLIME LAYER: unorganized and loose -Extracellular polysaccharide allows cells to ATTACH -Capsules prevent phagocytosis -VERY important in BIOFILMS
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Flagella of Prokaryote -Prokaryotic cells have this Gram (-) has how many rings? Gram (+) has how many rings? |
-Outside cell wall -made of chains of Flagellin -Attatched to a protein HOOk -Anchored to wall & membrane by basal body -Helicobacter pylori- stomach ulcers
(-)2 pairs (+) 1 -only inner ring |
Spirochetes move by 1) axial filaments
best known for Treponema pallidum (syphillis) Borrelia burgdorferi (lyme diseasea)
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- Endoflagella -bundles of fibrils that arise at end of cell beneath outer sheath -Rotation causes entire bacterium to move forward in corkscrew motion - motion allows it to go thru mucus & gain acces to hosts blood and lymph systems thru tissues and membranes |
Fimbriae & Pilli -gram negative bacteria -shorter, thinner & straighter than FLagella -used for attatchment and transfer of DNA rather then movement |
Pilin= structure consisting of protein, arranged in helical around central core- divided into two types. FImbriae & pilli
Fimbriae- used for attatchment -form biofilms -help bacteria stick
Pilli- not MAIN role of attcmt but CONJUGATION -transfer DNA from one cell to another
FImbria absent, then no disease can happen bc it cant colonize *help colonize mucous membranes (ex: gonorea) |
Bacterial cell wall - may allow certain Bacterial to cause disease |
- semi rigid structure -respoonsible for SHAPE -surrounds plasma membrane & protects cell from outside envt -prevents osmotic lysis -PEPTIDOGLYCAN walls in bacteria= site of action for antibiotics
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| Peptidoglycan assembled in cell wall |
-alternating NAM & NAG molecules linked to form carbohydrate "backbone" - Adjacent polypeptides are linked -4 amino acids attatched to NAMs in backbone -Penicllin interfers w/final linking of the peptidoglycan rows by peptide cross bridges -the wall weakens bc of this and cell undergoes lysis |
| Gram positive Cell Walls |
- MANY thick layers of peptidoglycan -contain teichoic acids |
| Gram Negative Cell wall |
-1 or very few layers of peptidoglycan & OUTer membrane -peptidoglycan is bonded to LIPOPROTEINS in outer membrane -NO teichoic acids -more suseptible to mechanical breakage -outer mem: LIPOpolysach., lipoproteins & phospholipids strong negative charge & barrier to antiobiotics -has porins |
| Difference bw Gram+ wall and Gram- wall |
+ -THICk peptidoglycan -Teichoic acids
- =Thin pep. -Outer membrane -periplasmic space |
GRam stain Mechanism -mechanism is based on differences in structures of cell wall 1)Crystal Violet- iodine crystals form in cell, dye enters cytoplams of both + and - gram -the iodine (the mordant) forms large crystals 2)Alcohol then dehydrates the peptidoglycan of gram+ to make more impermeable to crystal-violet iodine -on gram(-) it desolves outer membrane of thin pep. layer - |
Gram (+) -alcohol dehydrates peptidoglycan -CV-I crystals dont leave -Pink/Red
Gram (-) -Alcohol dissolves outer membrane & leaves holes in thin peptidoglycan -CV-I washes OUT Purple stain |
Atypical Cell Walls -have ACID-FAST cell walls
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-similar to gram (+) -WAXY LIPID (mycolic acid) bound to peptidoglycan -*Mycobacterium -* Nocardia -*Cant be gram stained -can b sstained w Carbolfuch. & heated -retain RED color -if mycolic acid layer is removed from stain wall of acid fast bacteria then it will stain GRAM+ in gram stain |
Atypical Cell Walls 1) Mycoplasmas 2) Archaea |
1) Lack cell walls -Sterols in plasma membrane (cholestorol in cell wall) -Pnemonia is wall less )fried egg appearance)
2) Wall LESS -or walls of PSEUDOmurein -(lack NAM and D amino acids) |
| Damage to cell Walls |
-Lysozyme digests disaccharide in peptidoglycan -active in most gram + bacteria (makes them vulnerable to lysis) -tears, mucus & saliva
-Penicillin INHIBITS peptide bridges in peptidoglycan |
Plasma Membrane -bilayer, selective permeable -Outer membrane only in Gram (-) -membrane is as viscous as olive oil -Proteins move to function -Phospholipids rotate & move laterlly |
In Prokaryotes: made of phospolipids - less rigid bc lack sterols -EXCEPT: Mycoplasms In Eurkaryotes: Carbs, sterols (cholestorl) |
Plasma Membrane -Selectively Permeable -Enzymes for ? -Chromatophores or Thylakoids -important for breakdown of nutrients & production of ATP |
- allows ppassage of some molecules -ATP prduction -Photosynthetic pigments.Found in infoldings that extend to cytoplasm
POLAR heads: 2 surfaces on lipid bilayer NONpolar tails: interior of bilayer |
| Damage to the Plasma Membrane does what? |
| Alcohols, quaternary ammonium (detergents) and antiobiotics cause leakage of cell contents |
Mvemt across Membranes 1) Simple diffusion 2) Faciliative Diffusion -dont need energy for this
3)Osmosis 4)Osmotic Pressure |
1)(perfume) mvmt of SOLUTE from HIGH concentration to LOW conc. 2)Solute combines w/transporter protein in membrane 3) Mvmt of WATER across a selectively permeable membrane from HIGH WATER to LOWER water concentration -OR from LOW SOLUTE conc. to HIGH solute 4) Pressure needed to stop mvmt of water across membrane |
1)Simple Diffusion & Facilited: NO energy required bc of going from HIgh SOLVENT to LOW 2) Osmosis: High SOLVENT to low |
1) cells rely on this to transport SMALL molecules like O2, CO2
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Mvmt of Materials across Membranes 1) Active Transport 2) Group Translocation |
1) Requires a transporter protein & ATP- NEED GLucose 2) Requires a transporter protein & PEP |
| Cytoplasm |
- Substance INSIDE plasma membrane -Contains Nuclear Region |
The PROKARYOTIC Ribosome
Eukaryotic Ribosome
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- Protein synthesis -70S
-80S |
