Home › ICAR JRF › Plant Sciences › Plant Form and Physiology › Why is transpiration described as a passive proc…
Why is transpiration described as a passive process?
ABecause it happens only while stomata are shut
BBecause it moves water in either direction
CBecause it stops whenever humidity is high
DBecause it needs no metabolic energy as ATP
Answer & Solution
Correct answer: D. Because it needs no metabolic energy as ATP
1. Transpiration is the loss of water vapour to the atmosphere through stomata.
2. It is passive, which means metabolic energy in the form of ATP is not required for the water to move.
3. The energy driving it is the difference in energy between the water in the soil and the water in the atmosphere.
4. Being passive does not mean uncontrolled, since transpiration is tightly regulated through the stomata.
_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_
Related questions
Which defence compound of the cassava root becomes toxic only after a herbivore eats it?A tree exposed to constant strong wind shows which developmental response?Jasmonates elicit the synthesis of volatile compounds that attract which agents?In ripening fruit, ethylene stimulates which conversion?Low soil moisture raises the level of abscisic acid, which then does what?Gibberellins are described as a group of about how many closely related hormones?The effect of cytokinins was first reported after adding what to plant embryos in culture?Which is the only naturally occurring auxin that shows physiological activity?