Bacteriology 1 Flashcards
What is a bacterium?
Single-celled microorganism that belongs to the prokaryote kingdom.
T/F: Bacteria have a nucleus.
False, no nucleus or membrane bound organelles.
How does cell division occur in prokaryotes?
Binary fission
T/F: A prokaryotic chromosome is circular and contains no histones.
True
How do bacteria grow?
They grow in aerobic, anaerobic or microaerophilic conditions, and some require cells to grow.
Name a few types of bacterial morphology/ shapes.
Cocci (spherical), Bacillus (rod-shaped), helical/ spiral shaped, curved/ comma shaped.
In gram positive bacteria, what compound is contained in the cell wall?
Lipoteichoic acid
In gram negative bacteria, what compound is contained in the outer membrane?
Lipopolysaccharide (LPS)
In mycobacteria, what unique component is located in the cell wall?
Mycolic acid
T/F: In gram positive, gram negative, and mycobacteria there is peptidoglycan in the cell wall.
True
In gram positive bacteria, what is Lipoteichoic acid used for?
Antigenicity
T/F LPS is an endotoxin found in gram negative bacteria and is antigenic.
True
What color do Gram positive bacteria stain?
Purple
Positive= Purple
What color do Gram negative bacteria stain?
Pink
Negative has an “n”, Pink has an “n”
What is the purpose of the alcohol wash when staining?
Decolorization
Acid fast staining is due to the presence of what?
Mycolic acid
Acid fast positive organisms are said to be stained pink. What is the name of the primary stain used?
Carbol fuchsin
When gram staining, what is the name of the counterstain used?
Safranin
When acid fast staining, what is the name of the counterstain used?
Methylene Blue
Why do acid fast negative bacteria get stained blue?
They get decolorized due to the absence of mycolic acid.
What are flagella used for?
Locomotion or motility.
Describe the structure of Amphitrichous flagella.
2 total, one on either side.
Where are the flagella located on Peritrichous?
Numerous all the way around
What are Pili/ fimbriae?
Small thread-like structures on bacterial surface.
What do Pili do?
Facilitate adherence to the host tissue through specific receptors.
What is a capsule?
Thick polysaccharide layer outside of the cell wall.
What is a capsule used for?
Sticking cells together, as a food reserve, as protection against desiccation and chemicals, helps bacteria to evade phagocytosis.
What is a survival mechanism for some gram positive bacteria?
Endospores
T/F: Spores are highly resistant dormant form of bacteria.
True
When are endospores produced?
When bacteria are exposed to adverse conditions & when essential nutrients are depleted.
Name the different phases of bacterial growth.
Lag phase, log phase, stationary phase, death phase.
How can bacterial growth be measured by?
Colony counting, turbidimetry, flow cytometer, hemocytometer chamber.
What is another name for the log phase?
Exponential phase
What kinds of bacteria require oxygen for growth?
Aerobic, microaerophilic, capnophilic
What kinds of bacteria do NOT require oxygen for growth?
Obligate anaerobe, aerotolerant anaerobe
What kinds of bacteria do not require oxygen, but can utilize it for growth?
Facultative anaerobe
