Why do plants give out oxygen in the day and carbon dioxide in the night?

Answer 1

Plants are living things and their metabolism constantly 'burns' food using Oxygen and producing CO2, they do this all the time, day and night.

However, during the day plant is bombarded by photons (i.e. light). The light allows the plant to photosynthesise, turning CO2 and water into Hydrocarbons for food and releasing Oxygen.

The amount of Oxygen produced is surplus to its metabolic requirements and is therefore released into the atmosphere.

At night photosynthesis closes down because there is no light so the plant consumes oxygen and releases CO2 like animals.

However, please note that there are a special group of plants (plants that live in desert climates) that have modified how and when they take up CO2.

In this special group of plants (called CAM plants) the CO2 enters the plant at night and is stored by the plant in special structures. This stored CO2 is then used for photosynthesis during the day but the plant takes in no new CO2 during daytime.

The CAM plants do this so as to prevent water loss during the hot daytime hours.

Answer 2

CO2 is used by the plants during sunlight in photosynthesis, which takes place during day time only. On the other hand, respiration which produces CO2 takes place day and night. Since CO2 is not utilized during night, it comes out of the plant at night.

Answer 3

plants give off oxygen in the day because of sunlight an we take in the oxygen and give off carbon dioxide.

Many plants do indeed take in CO2 at night.

In addition to performing photosynthesis which is Fixation of carbon to produce sugars (food) plants also carry on respiration (just like animals do). To do this they use some of the food (sugars) they created by photosynthesis and oxidize (using the same oxygen they produce by photosynthesis) it in order to produce energy to perform the myriad of energy intensive functions needed to be done by the plant. To take one example Trees must build strong fibers in order to grow tall and withstand the wind. To accomplish this they create cellulose and lignin which are polysaccharides (complex sugars). This is an energy intensive process and the energy comes from respiration. Some plants carry on such functions mainly at night.

Answer 4

At night, sunlight is not there to provide energy to create food. Plants still have metabolic processes to perform and use cellular respiration (as animals do), taking in oxygen and giving out carbon dioxide. This is on a much smaller scale than the daylight processes.

Answer 5

Because plants use the starches that they make with photosynthesis to grow to metabolise these takes oxygen in the same way as it does in animals. Plants grow and use oxygen at night.

Answer 6

Because there is no sunlight required for photosynthesis.Therefore,instead of producing oxygen,they consume oxygen and produce carbon dioxide.

Answer 7

During the day time, there is light coming from the sun. Plants need light to photosynthesise. At night, there is no light, so they can't photosynthesise. Instead, they respire

Answer 8

Because with out the sun they dont get as much replenishment.!