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

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
*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
-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
prokaryotes sometimes possess smaller extrachromosomal pieces of DNA called _____ - not critical for survival under normal conditions
usually one large circular molecules of DNA
bacterial chromosome
total DNA content
- 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
-composed of protein and RNA-found in both G+/-- synthesize proteins (important sites of action of antibiotics)-Inclusions (usually reserve materials - storage of materials)
acellular infectious agentconsists of nucleic acid (genome) enclosed in protein coat (capside-virally encoded)
what is an example of a slow viral infection?
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
protein coat surrounding nucleic acid
only found in SOME viruses
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
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?
cell lysis
enveloped viruses bud off
animal viruses

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