MICROBIOLOGY EXAM 2 PRACTICE TEST
QUESTIONS WITH CORRECT ANSWERS 2025/2026
Elements that are required in relatively large amounts by microorganisms are called...
A.multivitamins
B. meganurtients
C. macronutrients
D. macromolecules - CORRECT ANSWER -C. macronutrients
When a microorganism is placed in a(n) ________ solution, water will eneter into the cell and
cause it to burst unless something is done to prevent it.
A. hypotonic
B. isotonic
C. hypertonic
D. osomotic - CORRECT ANSWER -A. hypotonic
If cells are grown in media containing amino acids labeled with radioactive nitrogen, most of the
radioactivity will be found in the cells...
A. DNA
B. proteins
C. phospholipids
D. DNA and proteins
E. DNa and phosophlipids - CORRECT ANSWER -D. DNA and proteins
Micooraginams that grow best at temperatures between 45-70 degrees celsius are called:
A. Thermophiles
B. Psycrophiles
,C. Thermophobes
D. Mesophiles - CORRECT ANSWER -A. Thermophiles
Which of the following is an advantage of the standard plate count?
A. can readily count cells that fomr aggregates
B. determines the number of viable cells
C. can be performed on very dilute samples, such as lake water
D. provides immediate results
E. can be used to count heat-sensitive bacteria - CORRECT ANSWER -B. determines the number
of viable cells
The total number of viable microorganisms remains constant in stationary phase because:
A. there is a balance between cell division and cell death
B. there is a cessation of cell division even though the cells may remain metabolically activie
C. either a or b
D. niether a or b - CORRECT ANSWER -C. either a or b
Which of the following is NOT a direct method to measuree microbial growth?
A. direct microscopic count
B. standard plate count
C. filtration on a support membrane followed by incubation on medium
D. metabolic activity
E. most probably number - CORRECT ANSWER -D. metabolic activity
Media counting some ingredients of unknown chemical composition are called ______ media
A. undefined
, B. complex
C. defined
D. synthetic - CORRECT ANSWER -B. Complex
Which of the following is the best definition of generation time?
A. the length of time needed for lag phase
B. the length of time needed for a cell to divide
C. the minimum rate for 10 new cells to form
D. the duration of exponential growth phase
E. the timeneeded for nuclear division - CORRECT ANSWER -B. the length of time needed for a
cell to divide
A gene is best defined as...
A. a segment of DNA
B. three nucleotides that code for an amino acid
C. a sequence of nucleotides in DNA that codes for a functional product
D. a sequence of nucleotides in RNA that codes for a functional product - CORRECT ANSWER -C.
a sequence of nucleotides in DNA that codes for a functional product
How many nucleotide bases are found in the code for each amino acid?
A. 2
B. 3
C. 4
D. varies with the paricular amino acid - CORRECT ANSWER -B. 3
QUESTIONS WITH CORRECT ANSWERS 2025/2026
Elements that are required in relatively large amounts by microorganisms are called...
A.multivitamins
B. meganurtients
C. macronutrients
D. macromolecules - CORRECT ANSWER -C. macronutrients
When a microorganism is placed in a(n) ________ solution, water will eneter into the cell and
cause it to burst unless something is done to prevent it.
A. hypotonic
B. isotonic
C. hypertonic
D. osomotic - CORRECT ANSWER -A. hypotonic
If cells are grown in media containing amino acids labeled with radioactive nitrogen, most of the
radioactivity will be found in the cells...
A. DNA
B. proteins
C. phospholipids
D. DNA and proteins
E. DNa and phosophlipids - CORRECT ANSWER -D. DNA and proteins
Micooraginams that grow best at temperatures between 45-70 degrees celsius are called:
A. Thermophiles
B. Psycrophiles
,C. Thermophobes
D. Mesophiles - CORRECT ANSWER -A. Thermophiles
Which of the following is an advantage of the standard plate count?
A. can readily count cells that fomr aggregates
B. determines the number of viable cells
C. can be performed on very dilute samples, such as lake water
D. provides immediate results
E. can be used to count heat-sensitive bacteria - CORRECT ANSWER -B. determines the number
of viable cells
The total number of viable microorganisms remains constant in stationary phase because:
A. there is a balance between cell division and cell death
B. there is a cessation of cell division even though the cells may remain metabolically activie
C. either a or b
D. niether a or b - CORRECT ANSWER -C. either a or b
Which of the following is NOT a direct method to measuree microbial growth?
A. direct microscopic count
B. standard plate count
C. filtration on a support membrane followed by incubation on medium
D. metabolic activity
E. most probably number - CORRECT ANSWER -D. metabolic activity
Media counting some ingredients of unknown chemical composition are called ______ media
A. undefined
, B. complex
C. defined
D. synthetic - CORRECT ANSWER -B. Complex
Which of the following is the best definition of generation time?
A. the length of time needed for lag phase
B. the length of time needed for a cell to divide
C. the minimum rate for 10 new cells to form
D. the duration of exponential growth phase
E. the timeneeded for nuclear division - CORRECT ANSWER -B. the length of time needed for a
cell to divide
A gene is best defined as...
A. a segment of DNA
B. three nucleotides that code for an amino acid
C. a sequence of nucleotides in DNA that codes for a functional product
D. a sequence of nucleotides in RNA that codes for a functional product - CORRECT ANSWER -C.
a sequence of nucleotides in DNA that codes for a functional product
How many nucleotide bases are found in the code for each amino acid?
A. 2
B. 3
C. 4
D. varies with the paricular amino acid - CORRECT ANSWER -B. 3
