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28 Cards in this Set
- Front
- Back
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What is a bacterium?
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A single microorganism Prokaryotic-No nucleus Numerous Many are beneficial Few can cause damage |
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What is the only organelle in the cytoplasm of a bacterium? |
ribosome (small 70s) |
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What is the in the chemically complex bacterial cell wall? |
Peptidoglycan |
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What are other characteristics of bacteria? |
No cytoskeleton Binary Fission (no sex. reproduction) Aerobic/anaerobic/microaerophilic Some require cells to go Singular circular chromosome No histones |
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How often do bacteria divide? |
30 minutes = completed septum = 2 cells 60 minutes = 4 ells 90 minutes = 8 cells 120 minutes = 16 cells |
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What different types of morphology can bacteria have? |
Cocci-round Coccobacilli Bacilli-rod Helical-spiral (spirochetes) Curved- coma shaped |
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What is pleomorphic? |
Seen in many shapes |
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What is unique about gram positive bacteria? |
lipoteichoic acid (antigenicity-can trigger immune response) *thick cell wall |
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What is unique about gram negative bacteria? |
outer membrane containing lipopolysaccharide (LPS-virulence factor) *Thin cell wall |
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What does the Lipid A component do gram negative bacteria do? |
Endotoxin part of LPS that can activate the immune system and exert harmful effects on the host. Polysaccharide component contributes to antigenicity |
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What type of bacteria stains violet/blue? |
Gram positive |
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What makes the bacteria retain the violet/blue color? |
The thick wall of peptidoglycan prevents the crystal violet and grams iodine from escaping |
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What type of bacteria stains pink? |
Gram negative |
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Why does the bacteria stain pink? |
The thin peptidoglycan wall allows the crystal violet and grams iodine to pass through but hold the safranin stain |
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What color do acid fast organism stain and why? |
pink because the mycolic acid in the cell wall retains the carbol fuschin stain |
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What type of organisms are acid fast positive? |
gram positive |
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What makes the acid fast negative organism turn blue? |
Decolorizing (acid alcohol) makes it turn blue due to the absence of mycolic acid |
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Why is the structure on the surface of the bacteria important? |
It enhances virulence Can be used for identification |
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What are the different types of bacterial structures? |
Pili or Fimbriae Capsule Endospores |
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What do the pili/fimbriae do for the bacteria and what are examples of bacteria that have these? |
Small thread like structures facilitate adherence to host tissues through receptors and contribute to antigenicity Ex: Bordetellabronchiseptica and E. coli |
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What is the capsule useful for the bacteria? |
A thick polysaccharide layer used for: sticking cell together food reserve protection against desiccation evading phagocytosis |
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Why are endospores important for bacteria and what is an example of a bacteria that forms them? |
It's a survival mechanism for some Gram positive bacteria Highly resistant dormant form Produced when bacteria are exposed to adverse conditions Ex: Clostridium Bacillus |
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What can bacterial growth be measured by? |
Colony Counting Turbidimetry Flow Cytometer Hemocytometer Chamber (wbc counter) |
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What are the different phases of bacterial growth? |
Lag phase (beginning plateau) Log phase (exponential-increase) Stationary phase (middle plateau) Death phase (end-decline) |
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What is another way to identify bacteria? |
Their need for oxygen and nutrients |
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What are bacteria called that REQUIRE oxygen for growth? |
aerobic microaerophilic capnophilic |
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What are bacteria called that DON'T require oxygen or don't utilize it for growth? |
obligate anaerobe aerotolerant anaerobe |
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What are bacteria called that don't require oxygen but CAN utilize it for growth? |
facultative anaerobe |
