carrie norin so bravely stated:
Remembering a bit from high school, aren't we talking about ATP/ADP -
photosynthesis vs. respiration? Or are photosynthesis and respiration
concurrent and not separated by night and day.

photosynthesis and respiration can simultaneously occur - there are
certain plants that have specific adaptations (usually due to heat,
dessication, light, etc.) that either spatially (C4) or temporally
(CAM plants, which I think is causing the confusion here) separate the
influx of CO2 and the process of converting it to sugar. remember
that all living things respire, and so the sugars that plants produce
through photosynthesis that don't go to their structure (cellulose,
lignin, etc.) or shared with symbiotes (mycorrhizal fungi, etc.) are
burned for energy.

total generalizations:
photosynthesis takes water and CO2; using the energy from light
converts them to sugar and O2 (waste).
(aerobic) respiration takes sugar and O2; within the organism they get
converted to ATP and CO2 (waste).

Thanks for taking the time to answer my question, Carrie.

--
You can lead a horse to water, but you can't hold his head under 'til
the bubbles stop.
-
XX: Buddy