In respiration energy is released fromsugars when electrons associated with hydrogen are transported to oxygen (theelectron acceptor), and water is formed as a byproduct. The mitochondriause the energy released in this oxidation in order to synthesize ATP. Inphotosynthesis, the electron flow is reversed, the water is split (not formed),and the electrons are transferred from the water to CO2 and in theprocess the energy is used to reduce the CO2 into sugar. Inrespiration the energy yield is 686 kcal per mole of glucose oxidized to CO2,while photosynthesis requires 686 kcal of energy to boost the electrons from thewater to their high-energy perches in the reduced sugar -- light provides thisenergy.
Plants get carbon dioxide from the air through their leaves. The carbon dioxide diffuses through small holes in the underside of the leaf called stomata. (singular: stoma. plural: stomata)
The lower part of the leaf has loose-fitting cells, to allow carbon dioxide to reach the other cells in the leaf. This also allows the oxygen produced in photosynthesis to leave the leaf easily.
Carbon dioxide is present in the air we breathe, at very low concentrations. Even though it forms about .04% of the air, it is a needed factor in light-independent photosynthesis.
In higher concentrations, more carbon is incorporated into carbohydrate, therefore increasing the rate of photosynthesis in light-independent reactions.
Oxygen Cycle | Definition of Oxygen Cycle by Merriam …
Plants absorb water through their roots, and carbon dioxide through their leaves. Some glucose is used for respiration, while some is converted into insoluble for storage. The stored starch can later be turned back into glucose and used in respiration. Oxygen is released as a by-product of photosynthesis.
Oxygen is a chemical element with symbol O and atomic number 8
This process continues throughout the life cycle of a plant.
The ability of plants to produce foods is credited to the presence of chlorophyll and chloroplasts in the leaves.
This tutorial introduces photosynthesis
When teaching units on and or the , direct evidence of their occurrence is sometimes difficult to provide in a compelling form the laboratory. This exercise allows students to work directly with organisms and, via RUSS, an entire lake . Increasing concentrations in student built microcosms tested with water chemistry kits and daytime RUSS data provide evidence for photosynthetic activity. Decreasing oxygen concentrations in student built microcosms with fish and nighttime RUSS data provide evidence of respiration. The net balance of photosynthesis and respiration plays a major role in determining the level of oxygen present in lakes, particularly at depth in lakes. Oxygen levels at different depths differ if a lake is thermally stratified. Furthermore, as a byproduct of their larger will generally illustrate changes in oxygen concentration more dramatically than lakes which are less rich in nutrients and biomass.
BBC - GCSE Bitesize: Photosynthesis
The advantage that comes from this two-stage process is that the active pumping of carbon into the bundle sheath cell and the blocking of oxygen produce an environment with 10-120x as much CO2 available to the Calvin cycle and the tends to be optimally utilized. The high CO2 concentration and the absence of oxygen implies that the system never experiences the detractive effects of .