Microbial Growth Quiz
Preview:
In which phase is the bacteria most metabolically active?
A. Lag Phase
B. Log Phase
C. Exponential Phase
D. Death phase
A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?
A. thermophiles
B. acidophiles
C. mesophiles
D. psychrotrophs
What compound has the highest concentration in a cell?
A. CH4
B. CO2
C. H2O
D. glucose
Prokaryotes do not have
A. DNA
B. cell walls
C. membrane bound organelles
D. ribosomes
E. coli undergoes binary fission approximately every 20 minutes. If a culture started with 1000 cells, how many cells would be there be after 3 hours? (Given Nt=Ni x 2n)
A. 1000 x 29
B. 1000 x 23
C. 20 x 21000
D. 20 x 23
Which of the following is the reason jams and dried meats often do not require refrigeration to prevent spoilage?
A. low pH
B. toxic alkaline chemicals
C. naturally occurring antibiotics
D. low water activity
The stage in population growth with the highest rate of cell division is the
A. stationary phase
B. lag phase
C. exponential phase
D. enlargement phase
Which of the following is the best definition of generation time in a bacterium?
A. the length of time it takes to reach the log phase
B. the length of time it takes for a population of cells to double
C. the time it takes to reach stationary phase
D. the length of time of the exponential phase
pH requirement for molds and yeast?
A. 6.5-7.5
B. 5-6
C. 7-8
D. 3
These microorganisma can grow at a temperature range of 10 to 50 oC
A. psychrophiles
B. psychrotrophs
C. mesophiles
D. thermophiles
Which term best describes a bacteria that cannot exist in the presence of oxygen?
A. Obligate aerobe
B. Facultative aerobe
C. Obligate anaerobe
D. Facultative anaerobe
Which group of organisms is most likely to infect humans
A. psychrophiles
B. mesophiles
C. thermophiles
D. hyperthermophiles
Which statement is correct?
A. Archea have internal membrane- bound
B. Most yeasts reproduce by budding
C. Fungi are photosynthetic microorganisms
D. Bacteria need lower moisture content to grow than molds
Extremely high temperatures can cause a decline in bacterial growth because
A. heat increases metabolic rate and creates more waste products.
B. heat slows down metabolic rate.
C. heat denatures enzymes/proteins, DNA, and causes leaky membranes.
D. heat prevents DNA from replicating.
During the stationary phase, bacteria are
A. dying at a faster rate than reproduction.
B. doubling in number every generation.
C. reproducing at the same rate as they are dying.
D. making proteins, ribosomes, and obtaining nutrients.
