Recent estimates suggest that a human body is made up of ~37 trillion (that’s 3.

Question

Recent estimates suggest that a human body is made up of ~37 trillion (that’s 3.7 × 1013) individual cells. However, for each human cell, there are approximately three microbial cells (bacteria, archae, fungi, etc; 500-1000 species!) living in or on the body. Estimate the mass of this human “microbiota,” using the following assumptions:

Each microbial cell is a cylinder 2mm in diameter and 8mm long (volume of a cylinder is p r2 × l); and

The density of the microbial cells is that of water (1g/cm3)

Explanation / Answer

Number of human cells= 3.7 X 10 13

Hence, Number of Microbial cells = 3 X  3.7 X 10 13 = 1.11 X 10 14 ( since it is mentioned, for each human cell, there are approximately three microbial cells (bacteria, archae, fungi, etc; 500-1000 species!) living in or on the body. )

Volume of each microbial cell (assuming it is cylindrical) = pi X r2 X l

= (22/7 X 12 X 8) cubic mm = 25.1428 cubic mm

= 0.025 cubic cm ( since 1 cubic cm = 1000 cubic mm)

Mass of each microbial cell = Density X Volume ( since Density = Mass/ Volume)

= ( 1 X 0.025) g/cm3 = 0.025   g/cm3

Hence, total mass of the human microbiota= 0.025 X 1.11 X 10 14 = 2.775 X 1012

Related Questions

Navigate

• Browse (All)
• Browse R
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.