Plants produce oxygen in photosynthesis. Where does the oxygen come from?

Question

a. the sun
b. chlorophyll
c. glucose
d. water
e. a turn of the Calvin / Benson cycle

Answer 1

d) The oxygen comes from water. The actual mechanism is still not completely understood. In chlorophyll there is what's called the 'oxygen evolving complex'. This complex uses the sun's energy to strip protons from the water and release oxygen gas as a waste product.

Plants use carbon dioxide to make glucose. Oxygen is not the byproduct of the conversion of CO2. Those oxygens go into the glucose molecule.





Follow tinkertailorcandlestickmaker's link to Wikipedia. You will see that oxygen is NOT produced from carbon dioxide:

3 CO2 + 9 ATP + 6 NADPH + 6 H+ → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+ + 3 H2O

But produced from water:

2 H2O + 2 NADP+ + 2 ADP + 2 Pi + light → 2 NADPH + 2 H+ + 2 ATP + O2

Answer 2

D. Plants split water molecules using energy in the light-dependent reactions. They keep the H+ and associated electron to use and discard the oxygen. A. The sun gives light which is the energy that drives photosynthesis and splits the water, but it's not the source of the oxygen. B. Chlorophyll absorbs the light energy and passes an electron down the electron transport chain, producing the energy to split water, but it's not the source of the oxygen either. C. Glucose is the end product of photosynthesis. E. The Calvin cycle builds glucose. Water has already been split and oxygen released in the preceding light-dependent reactions.

Answer 3

It is taken from the carbon dioxide and water as a waste product of photosynthesis. Sun energy and chlorophyll are needed for process but are not where oxygen comes from.

Calvin Benson makes glucose in the dark.

That makes them all wrong.

Answer 4

I don't know who Calvin or Benson is, but I will choose:

f. none of the above.

The oxygen released by plants through photosynthesis comes mostly from carbon dioxide in the air. The plants take the carbon dioxide, strip of the carbon to provide the primary mass for plant growth, and release the oxygen.

Answer 5

Water

Answer 6

Photosynthesis uses light energy and carbon dioxide to make sugars like glucose.
Carbon dioxide + water + light = sugar + oxygen

The oxygen comes from the Carbon dioxide and water.
d) is the answer closest to correct.

Answer 7

this oxygen comes from water.

during light reaction stage of photosynthesis, photolysis(ie.breaking down of water in the presence of light) takes place.
i.e water gets broken into 2hydrogen ions,half molecule of oxygen nd releases 2 electrons.this oxygen is either released into the air or used 2 respiration by plants

Answer 8

This has already been answered, but since there are conflicting answers, I'll cast a vote for DanE's answer, the oxygen comes from both co2 and water, (d) is the closest answer.

Answer 9

it actually comes from D) water....in the LIGHT phasethe water when exposed to heat and light breaks up to give out hydrogen and water which is also known as the splitting up of water.....






sHaKiRa

Answer 10

photolysis of water
H2O-->2H+O
O+O-->O2