Which of the following best approximates the mass of a typical bacterial cell?

• A. 1 picogram (1 × 10^{-12} g)
• B. 1 microgram (1 × 10^{-6} g)
• C. 1 milligram (1 × 10^{-3} g)
• D. 1 nanogram (1 × 10^{-9} g)

Answer: (A)

Verified step by step guidance

1. Understand the scale of bacterial cells: typical bacterial cells are microscopic and much smaller than cells of multicellular organisms, so their mass is expected to be very small.
2. Recall that a picogram (pg) is \$1 \times 10^{-12}\( grams, a nanogram (ng) is \)1 \times 10^{-9}\( grams, a microgram (\u03bc g) is \)1 \times 10^{-6}\( grams, and a milligram (mg) is \)1 \times 10^{-3}$ grams.
3. Consider the approximate size and density of a bacterial cell, which is usually around 1 micrometer in length and has a density close to water, meaning its mass is roughly equivalent to the volume in cubic micrometers times the density.
4. Estimate the volume of a typical bacterial cell (e.g., a rod-shaped bacterium) using geometric formulas (such as volume of a cylinder or sphere) and convert that volume to mass assuming the density is about 1 g/cm³.
5. Compare the estimated mass to the given options and identify which order of magnitude (picogram, nanogram, microgram, milligram) best fits the typical bacterial cell mass.