Chapter 6 (textbook) Flashcards
(30 cards)
A coulter counter is a….
device that directly counts microbes as they pass through a tube in front of an electronic detector
Which method is the best for counting fecal bacteria from a stream to determine the safety of the water for drinking?
Membrane filtration
which of the following is most useful in representing population growth on a graph?
A) log reproduction of the growth curve
B) Semilogarithmic graph using log scale on y axis
C) an arithmetic graph of the lag phase followed by a logarithmic section for the log, stationary, and death phases
D) none of the above
B) semilogarithmic graph using log scale on y axis
In a defined medium…
A) the exact chemical composition is known
B) Agar is available for microbial nutrition
C) blood may be included
D) organic chemicals are excluded
A) exact chem. comp. is known
Which term best describes an organism that cannot exist in the presence of oxygen
Obligate Anaerobe
Barophiles... A) cannot cause disease in humans B) live at normal temp. C) die if put under water D) thrive in warm air
A) cannot cause disease in humans
ORganisms that preferentially may thrive in icy waters are described as…
psychrophiles
Which of the following are not a growth factor? A) Cholesterol B) Vitamins C) water D) Heme
C) water
Microaerophiles that grow best with a high concentration of CO2 in addition to low oxygen are called…
Capnophiles
What is the most reactive of the four forms of toxic oxygen?
Hydroxyl Radical
Superoxide dismutase detoxifies what?
Superoxide (toxic form of oxygen)
“in a the laboratory, a sterile inoculating loop is moved across the agar surface in a dulture dish, thinning a sample and isolating individuals” this statement describes what?
Streak Plate
Which of the following can grow in a Petri Plate on a laboratory table?
An Aerobic Bacterium
Lyophilization can be describes as
freeze drying
all cells require a source of ______ for redox reactions
electrons
A toxic form of oxygen, _____ oxygen is a molecular oxygen with electrons that have been boosted to a higher energy state
singlet
All cells recycle the essential element ____ from amino acids and nucleotides
nitrogen
_____ are small organic molecules that are required in minute amounts for metabolism
Growth factors
The lowest temp at which a microbe continues to metabolize is called its___________
min. growth temp
Cells that shrink in hypertonic solutions such as saltwater are responding to _______ pressure
osmotic
Obligate _______ exist in salt ponds because of their ability to withstand high osmotic pressure
halophiles
________ pigments protect many phototrophic organisms from photochemically produces singlet oxygen
Carotene
Microbes that reduce N2 to NH3 engage in Nitrogen ______
Fixation
A student observes a researcher streaking a plate numerous times flaming the loop between streaks. The researcher is likely using the ______ method to isolate the microorganism
streak
