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81 Cards in this Set
- Front
- Back
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Prokaryote
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genetic material not bound by nuclear envelop but loosely arranged in the cytoplasm called nucleoid
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Eukaryote
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genetic material bounded by nuclear envelope = nucleus
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Virus
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protein capsid + genetic material
*can only replicate within host cell |
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Prion
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host cellular protein that changes to an abnormal conformation and can cause other normal proteins to have the same conformational change
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Eubacteria
Size Type of genetic material |
0.2 micrometer x 0.2 - 20 micrometers
ds DNA - usually circular |
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capable of self replication?
Cellularity? |
Yes
*Exceptions: Rickettsia, Coxiella, Chlamydia Unicellular |
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nuclear envelope?
membrane bound organelles? Ribosomes? |
No
No 70S |
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Cell Wall?
Membranes? |
Yes - *except Mycoplasma & Ureaplasma
Inner (cytoplasmic membrane) & Outer *gram + and acid fast |
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Eukaryotes = fungi, protozoa, helminths, arthropods
Size? Genetic material? |
2 micrometers - 0.8 m
ds DNA - linear |
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Capable of self replication?
Cellularity? |
Yes
Unicellular or multicellular |
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nuclear envelope?
membrane-bound organelles? Ribosomes? |
Yes
Yes 80S |
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Cell Wall?
Membranes? |
Yes (fungi & plants) & No (animals)
Cytoplasmic |
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Viruses - many groups
Size? Genetic material? |
0.01 - 0.2 micrometers
DNA or RNA/ ds OR ss |
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Capable of self replication?
Cellularity? Membranes? |
No
Non-cellular Some have a lipid envelope |
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Morphological types of bacteria:
diplococci steptococci staphylococci bacilli coccobacilli vibrios spirals |
See pictures on pg. 13 of syllabus
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cytoplasmic mesosomes
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extensions of cell membranes that are important in formation of septae between daughter
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plasmids
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extrachromosomal genetic elements found in many bacteria that often contain genes for toxins and antibiotic resistance enzymes
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peptidoglycan
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continuous matrix of linear polysaccharides crosslinked by peptides
*present in all bacteria except Mollicutes (include Mycoplasma & Ureaplasma) |
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True or False:
cell wall prevents the cell from rupturing despite the high osmotic pressure |
True
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What enzyme can be used to disrupt polysaccharide linkages to produce viable cells without cell walls?
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Lysozyme
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spheroblasts
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gram negative cells with cell wall disrupted
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protoblasts
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gram positive with cell wall disrupted
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L form
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cell wall-free bacteria formed in vivo due to the action of antibiotics
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Peptidoglycan is synthesized by enzymes located _____?
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in the cytoplasmic membrane
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The polysaccharide portion consists of which 2 repeating units?
and are called? |
N-acetyl glucosamine and N-acetyl muramic acid
(NAG - NAM) called: glycans |
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Glycans are covalently bound to tetrapeptides that contain:
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D and L amino acids
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Tetrapeptides of different polysaccharide chains are crosslinked by enzymes called_____?
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transpeptidases
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What is the mode of action for Penicillin and other beta-lactam antibiotics?
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bind covalentyl to bacterial transpeptidases to inhibit crosslinking of the polysaccharide chains which leads to cell lysis
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Cell envelope includes:
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cytoplasmic membrane + cell wall + outer membrane (if present)
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Gram negative cell envelope characteristics
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thin peptidoglycan layer
outer membrane |
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Outer membrane structure
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LPS
Porins Lipoprotein |
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LPS has 3 covalently linked components which are?
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Lipid A
core polysaccharide O Antigen (polysaccharide side chain) |
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Lipid A
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complex lipid which anchors LPS to the outer surface of the outer membrane
**Toxic to humans |
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Core polysaccharide
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same in most bacteria
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O antigen
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long chain consisting of repeating 3-sugar units; different sugar composition in different bacteria
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Porins
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can be selective; permit small MW compounds to diffuse across the outer membrane
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Lipoproteins
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small MW protein which covalently links the outer membrane to the peptidoglycan layer
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periplasmic space
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area between the outer membrane and cytoplasmic membrane in gram negatives
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gram positive envelope
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thick peptidoglycan cell wall with NO outer membrane
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Gram + cell wall contains high concentrations of ______ ____ which anchors the cell wall to the cytoplasmic membrane.
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lipotechoic acid
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Acid fast envelope
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similar to gram + but contains a high concentration of waxy, long chain fatty acids called: MYCOLIC ACID
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Acid fast bacteria include:
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Mycobacterium tuberculosis and leprae
some actinomycetes |
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What does the term acid fast mean?
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refers to stains that penetrate the waxy cell wall cannot be washed out with acidified alcohol
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True or False:
Substance in acid fast bacteria cell wall inhibit the killing of mycobacteria by phagocytosis |
True
*This allows them to survive and grow within macrophages for months or years and stimulate T cell responses |
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Flagella are long, helical cell appendages usually consisting of a single protein called _______.
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Flagellin
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Flagella are not found in which bacterial morphology?
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cocci
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True or False;
Motility is an important virulence factor in bacterial infections |
True
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Polar flagella
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flagella located at the ends only
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Peritrichous flagella
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flagella is distributed over the entire surface of the cell
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Rotation of the flagella occurs via the _________.
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flagellar basal body
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Rotation in the correct direction causes ________ motion. Rotation in the opposite direction causes ______ motion.
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translational (locomotion)
tumbling (little net movement) |
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Fimbriae or Pili
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nonmotile protein filaments which extend from the surface of some types of bacteria
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Pili are important for ________ which is an important virulence factor.
Give examples of bacteria who require pili for virulence. |
adherence
N. gonorrhoeae and invasive strains of E. coli |
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Bacteria that contain conjugative plasmids express ______ pili.
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conjugative or sex pili
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A bacteria containing the F plasmid is called ___ and will transfer DNA to a ___.
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F +
F - |
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Some bacteria have a polysaccharide or polypeptide layer outside the cell envelope called a _____.
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capsule
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Bacterial colonies that express _____ generally have large glistening, mucoid colonies.
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capsules
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The capsular layer protects bacteria from ______ by host neutrophils and macrophages. If antibodies ______ the bacterium it will become susceptible to phagocytosis.
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phagocytosis
opsonize |
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Give up to 4 examples of encapsulated bacteria.
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S. pneumoniae*
Klebsiella pneumoniae* Bacillis anthracis** Yersinia pestis** *polysaccharide capsule **polypeptide capsule |
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Name 5 secreted components which are important in bacteria survival and pathogenesis.
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Exotoxins
Proteases Siderophores Bacteriocins Antibiotics |
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Metabolically inactive forms of bacteria which are highly resistant to heat and dessication are ?
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Endospores
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Only gram + rods of the genera _____ and ______ produce endospores.
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Bacillus
Clostridium *tend to produce powerful toxins and cause fatal diseases (anthrax, tetanus, gangrene, botulism) |
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_________ occurs when a bacterium in the normal vegetative state is exposed to adverse conditions such as depletion of nutrients.
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sporulation
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More than 30 sporulation genes are activated that results in formation of a thick coat called the ________ around chromosomal DNA.
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Cortex
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Sporulation genes also result in decreased water content, accumulation of calcium and an amino acid precursor called _______ ____.
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Dipicolinic acid
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True or false.
Endospores are completely dormant but can be killed at high temperatures, such as in boiling water. |
FALSE
Endospores are completely dormant and can survive high temperatures such as boiling water. |
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________ occurs as a result of exposure of endospore to heat or incubation in a good growth environment causing ATP production and RNA synthesis to allow the spore to ________ and reture to the normal, vegetative state.
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Activation
germinate |
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Most spore-forming organisms are _______ organisms which can be introduced into the host by improperly canned food or by injury.
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normal soil organisms
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Name genotypic characteristics used to classify bacteria.
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DNA homology
G+C ratio Ribosomal RNA sequences DNA and protein sequences |
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Name phenotypic characteristics used to classify bacteria.
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Staining characteristics
Morphology Sporulation Oxygen dependence/tolerance Motility Growth requirements Enzyme activities Substrate utilization patterns Colony characteristics |
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Name medically important genera for each of the following principle groups of bacteria.
Spirochetes |
Treponema
Borrelia Leptospira |
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Mycelial (actinomycetes)
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Mycobacterium
Actinomyces Nocardia Streptomyces |
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Obligate intracellular parasites
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Rickettsia
Coxiella Chlamydia |
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Gram + Cocci
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Streptococcus
Staphylococcus |
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Gram + Non-sporulating rods
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Corynebacterium
Listeria Erysipelothrix |
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Gram + Sporulating rods
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Bacillis
Clostridium |
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Gram - Cocci
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Neisseria
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Gram - Non-enteric rods
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Spirillum
Pasteurella Brucella Yersinia Francisella Haemophilus Bordatella Legionella |
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Enteric rods:
Facultative anaerobes |
Escherichia coli
Salmonella Shigella Klebsiella Proteus Vibrio |
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Enteric rods:
Obligate aerobes |
Pseudomonas
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Enteric rods:
Obligate anaerobes |
Bacteroides
Fusobacterium Mycoplasma |
