BIOL 2051 LAB FINAL PRACTICE QUESTIONS WITH DETAILED EXPLANATIONS 2026

BIOL 2051 LAB FINAL MOCK TEST WITH
ANSWER RATIONALES 2026

◉ + control for motility test medium
Answer: Escherichia coli (motile)


◉ - control for motility test medium
Answer: Staphylococcus epidermidis (non-motile)


◉ Direct microscope count
Answer: -uses cell counting chamber (hemocytometer)
-counts both living and dead cells


◉ Units for direct microscope count
Answer: cells/mL


◉ Organism tested by direct microscope count
Answer: Saccharomyces cerevisiae


◉ Standard plate count (AKA viable cell count)
Answer: -counts only living cells

,-based on assumption that 1 living cell will give rise to a colony


◉ Units for standard plate count
Answer: cfu/mL


◉ Organism tested (by bench 4) for standard plate count
Answer: broth culture of Escherichia coli


◉ Tubidimetric assay
Answer: -counts both living and dead cells
-turbidity increases as # of cells increases
-measure amount of light at 600 nm; amount of light transmitted
through broth decreases as # of cells increases
-used to create a standard curve (line graph) correlating
ABSORBANCE (y-axis) with total cfu (x-axis)


◉ Organism tested by turbidimetric assay
Answer: dilution of Escherichia coli


◉ Survival
Answer: -temperature
-UV

, ◉ Growth
Answer: -pH
-salinity


◉ Thermophile
Answer: 45-80° C


◉ Extreme thermophile
Answer: >80° C


◉ Mesophile
Answer: 20-45° C


◉ Psychrophile
Answer: <20° C


◉ UV of _____ nm is most damaging to nucleic acids.
Answer: 260


◉ Organism that can quickly repair UV-damaged DNA
Answer: Deinococcus radiodurans