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A pressure potential of 1.5 MPa is equivalent to about how many pounds per square inch?
A30
B70
C140
D210
Answer & Solution
Correct answer: D. 210
1. One megapascal converts to about 140 pounds per square inch.
2. Multiplying 1.5 megapascals by 140 pounds per square inch per megapascal gives 210 pounds per square inch.
3. So a turgor pressure of 1.5 MPa equates to 210 pounds per square inch.
4. For comparison, most automobile tyres are kept at 30 to 34 pounds per square inch, so a turgid cell is far above tyre pressure.
5. The value 140 is the conversion factor itself and is the trap for a reader who forgets to multiply by 1.5.
6. The value 30 is the tyre comparison rather than the cell pressure.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.5 Transport of Water and Solutes in Plants_
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