MIC 205- Characteristics Of Bacteria (GRAM + / - )

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Mic 205 Final Study Guide- Characteristics Of Bacteria; Gram +/-

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- one of most important sites for attack by antibiotics-cause symptoms of disease in animals-provides structure + shape; protects it from lysis and noxious chemicals
 
cell wall
2 main wall types:
 
gram +gram -
divides bacteria into 2 groups depending on if they retain crystal-violet-iodine stain
 
Gram Stain
purple/blue-wall contains thicker layer of peptoglycan
 
Gram +
pink/red-not as much peptoglycan, and has extra outer membrane
 
Gram -
*thick cell walls- extend beyond cell wall + capsule of encapsulated bacteria*may regulate movement of ions in and out cell*lysosome- digests intact peptidoglycan by cleaving glycosidic bonds that link sugars together
 
gram +
*on outside of peptidoglycan layer-chemically distinct from usually biological membranes-can resist damaging chemicals
 
Outer bilayer membrane of Gram - cell wall
-on outer membrane-unique to G--LPS covalently attached to thin peptidoglycan layer (cell wall) by lipoproteins
 
LPS (lipopolysaccharide)
- gap b/w cell membrane and outer membrane of G-- metabolically active space
 
periplasm
*thick peptidoglycan layer*purple - retain the crystal violet-iodine of g-stain
 
gram +
*thin peptidoglycan layer  + outermembrane*red/pink - do not retain crystal violet, stained w/ counter stain
 
Gram -
-encloses cell cytoplasm-in both G +/-
 
cytoplasmic membrane
contains proteins (up to 200 different kinds)
 
phospholipid bilayer in cytoplasmic membrane
what carries out most membrane functions?
 
proteins in bilayer
-secretion of extracytoplasmic proteins-responses to environmental signals
 
functions of cytoplasmic membrane        
phospholipid bilayer is _________ to most substances
 
impermeable
-function as pores, channels, or carriers-movement can be passive or active
 
membrane proteins (transport systems)
- found in both G +/-- contains genetic information-ribosomes-proteins and enzymes-bacterial chromosome-plasmids-genome
 
cytoplasm
prokaryotes sometimes possess smaller extrachromosomal pieces of DNA called _____ - not critical for survival under normal conditions
 
plasmids
usually one large circular molecules of DNA
 
bacterial chromosome
total DNA content
 
genome
- no nuclear membrane!-nucleic acids-found in G +/-contains bacterial genome (DNA)
 
  Nucleoid or nuclear region
-small extrachromosomal circular DNA molecule-found in both G +/- bacteria-not required for life or reproduction in normal environment-can contain genes that encode resistance to antibiotics, heavy metals, and virulence genes
 
plasmid
-composed of protein and RNA-found in both G+/-- synthesize proteins (important sites of action of antibiotics)-Inclusions (usually reserve materials - storage of materials)
 
Ribosomes
acellular infectious agentconsists of nucleic acid (genome) enclosed in protein coat (capside-virally encoded)
 
viruses
what is an example of a slow viral infection?
 
HIV
only reproduce inside living host cells 
 
viruses -obligate intracellular parasites
some replicate in cytoplasm and some in nucleus-viral replication site in host cell is dependent upon type of _____
 
viral nucleic acid
viruses infect every known cell type- 
 
microbial, plant and animal
viral nucleic acid structure
 
either DNA or RNA, never both
-come as RNA-bring in their own enzymes and copy their RNA to DNA
 
retroviruses
protein coat surrounding nucleic acid
 
capsid
only found in SOME viruses
 
Envelope
glycoproteins
 
spikes
Virus life cycle:_____ & entry into host cellvirus hijacks _____ & ______ abilities of cell for __________makes ____ and arranges escape from cell
 
attachmentbiosyntheticprotein synthesizingreplication of nucleic acidviral proteins
DNA replication, transcription , and translation occur in cytoplasm
 
prokaryotes-have cell wall-only viral nucleic acid inters cell
DNA replication and transcription in nucleustranslation in cytoplasm
 
eukaryotes
five main stages: (bacteria + animal virus)
 
1. attachment2. penetration3. viral synthesis4. assembly & packaging5.virus release from infected host cell
-replication-production of viral protein & nucleic acid-how this occurs depends on whether the infection viral nucleic acid is DNA or RNA.
 
viral synthesis
what is an example of assembly and packaging of new virus particles?
 
capsid
cell lysis
 
bacteriophage
enveloped viruses bud off
 
animal viruses
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