Q. If a plant is releasing carbon dioxide and
taking in oxygen during the day, does it
mean that there is no photosynthesis
occurring? Justify your answer ?
Ans. Respiration is the process of oxidation
of food substances that release carbon
dioxide; it takes place throughout the day.
Photosynthesis is the process of fxing the
atmospheric carbon dioxide into organic
compounds (carbohydrates) with release of
oxygen gas as by product. Photosynthesis
takes place during the day in presence of
The CO2 released during respiration is
absorbed by plants for photosynthesis
during day causing net release of oxygen
only. If a plant is releasing carbon dioxide
and taking in oxygen during the day, it
means that either rate of photosynthesis is
too slow to counter balance the release of
CO2 by respiration or photosynthesis is not
taking place at all.