Foundations of Microbiology
What type of organism causes disease in host?
Pathogen
Which structure is found ONLY in eukaryotic cells?
nucleus
ATP is directly required for which type of transport?
active transport
Gram-positive bacteria retain crystal violet due to what feature?
thick peptidoglycan layer
Total magnification is calculated by multiplying which two lenses?
ocular lens and objective lens?
Which process violates the principle of spontaneous generation?
biogenesis
Prokaryotic DNA is BEST described as which of the following?
single circular chromosome
Which process allows diffusion of gases across membranes?
passive diffusion
Lysozyme damages bacteria by targeting which structure?
peptidoglycan in the bacterial cell wall
A simple stain would be MOST useful for determining which feature?
cell shape, size, and arrangement
Fermentation differs from respiration in its use/not use of what molecule?
electron transport chain/oxygen
Which feature MOST clearly distinguishes prokaryotes from eukaryotes?
absence of membrane-bound organelles
Active transport differs from passive transport in which key way?
the requirement of energy (ATP) and movement against a concentration gradient
Endospores are MOST accurately described as what?
dormant survival structure
Why is oil immersion REQUIRED at 100× objective magnification?
Increasing resolution by reducing light refraction
Normal microbiota are MOST important for which function?
prevention of pathogen colonization
competitive exclusion
Prokaryotes divide via
Binary Fission
A cell placed in a hypertonic solution will MOST likely do what?
shrink
A Gram-negative bacterium appears pink due to which step of staining?
alcohol/acetone decolorization removing crystal violet
During Gram staining, failure to decolorize would MOST affect which cells?
Gram-negative cells
An increase in disease incidence worldwide is BEST explained by which factor?
global travel and population density
The endosymbiotic theory is supported by which observation
Mitochondria and chloroplasts have their own DNA and ribosomes
High NaCl environments inhibit bacterial growth primarily due to what effect?
osmotic stress, causing water to leave the cell
What is the process of preparing a smear and staining?
Smear > Fix > Stain
crystal violet, iodine, alcohol, safranin
If an image is dark and blurry, which microscope adjustment should be checked FIRST?
The diaphragm or light intensity control