Photosynthesis vs. Photorespiration

Photosynthesisnoun

(biology) Any process by which plants and other photoautotrophs convert light energy into chemical energy,

Photosynthesisnoun

principally, oxygenic photosynthesis, any process by which plants and algae convert water and carbon dioxide into carbohydrates and waste oxygen using solar energy.

Photosynthesisnoun

also, non-oxygenic photosynthesis, used by purple and green bacteria, heliobacteria, and acidobacteria.

Photosynthesisnoun

The process of constructive metabolism by which carbohydrates are formed from water vapor and the carbon dioxide of the air in the chlorophyll-containing tissues of plants exposed to the action of light. It was formerly called assimilation, but this is now commonly used as in animal physiology. The details of the process are not yet clearly known. Baeyer's theory is that the carbon dioxide is reduced to carbon monoxide, which, uniting with the hydrogen of the water in the cell, produces formaldehyde, the latter forming various sugars through polymerization. Vines suggests that the carbohydrates are secretion products of the chloroplasts, derived from decomposition of previously formed proteids. The food substances are usually quickly translocated, those that accumulate being changed to starch, which appears in the cells almost simultaneously with the sugars. The chloroplasts perform photosynthesis only in light and within a certain range of temperature, varying according to climate. This is the only way in which a plant is able to organize carbohydrates. All plants without a chlorophyll apparatus, as the fungi, must be parasitic or saprophytic.

Photosynthesisnoun

synthesis of compounds with the aid of radiant energy (especially in plants)

Photosynthesis

Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's metabolic activities. This chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek phōs (φῶς), , and sunthesis (σύνθεσις), .

Photorespirationnoun

(biology) the light-dependent release of carbon dioxide and uptake of oxygen in photosynthetic organisms; an unavoidable side reaction of photosynthesis

Photorespiration

Photorespiration (also known as the oxidative photosynthetic carbon cycle, or C2 photosynthesis) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis. The desired reaction is the addition of carbon dioxide to RuBP (carboxylation), a key step in the Calvin–Benson cycle, but approximately 25% of reactions by RuBisCO instead add oxygen to RuBP (oxygenation), creating a product that cannot be used within the Calvin–Benson cycle.