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Q & A: Plant respiration and photosynthesis

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Most recent answer: 05/16/2013
Q:
what are the differences between respiration (in plants) and photosynthesis?
- Lim Zhao Liang (age 8)
Tampines North Primary School, SIngapore
A:
Hi Lim Zhao,

Plants, like all other living organisms, need to make use of stored chemical energy in order to perform their life functions -- to grow, to transport nutrients, to reproduce, and to protect themselves. They do this all the time, using free oxygen from the air and use the sugars that they have stored inside to make carbon dioxide and water. Sounds backwards from what a plant ought to be doing! Plants are special in that they also perform an almost reverse reaction, that of converting carbon dioxide and water and other nutrients found in the soil into sugars plus oxygen, via photosynthesis, aided by the molecule chlorophyll.

Here's a to learn more about this fascinating reaction.

Plants can only perform photosynthesis during the daytime, and leafy trees drop their leaves in the autumn in temperate climates, so they are unable to perform photosynthesis in the winter. They still perform respiration in order to use stored energy and survive during these times, though.

Tom

(published on 10/22/2007)

Follow-Up #1: Oxygen from Tulsi

Q:
The plant Tulsi gives out oxygen day and night making use of Ozone is it true? If so, the chemical formula, please.
- Bhikhu Patel (age 75)
San Jose CA USA
A:
I suspect not.   Green leaves of plants manufacture oxygen by inhaling carbon dioxide from the atmosphere and using sunlight in a process called photosynthesis.  I haven\'t heard of plants consuming O3. Take a look at

for some more information.

LeeH

(published on 05/16/2013)

Follow-up on this answer.