What is photorespiration and its mechanism?
Photorespiration is a process which involves loss of fixed carbon as CO2 in plants in the presence of light. It is initiated in chloroplasts. This process does not produce ATP or NADPH and is a wasteful process. Photorespiration occurs usually when there is the high concentration of oxygen.
How does photorespiration occur?
Photorespiration generally occurs on hot, dry, sunny days causing plants to close their stomata and the oxygen (O2) concentration in the leaf to be higher than the carbon dioxide (CO2) concentration. As a plant’s environment becomes hot, dry, and bright, its stomata, where carbon dioxide enters the leaf, tend to close.
What is RuBP photorespiration?
The first step of photorespiration is oxygenation. It is catalyzed by RUBISCO and converts RUBP to one molecule fo 3PGA and one molecule of 2PG, which is a 2 carbon compound with one phosphate group. The oxygenation reaction is influenced by environmental factors.
Why is C4 pathway called?
Some plants have evolved a supplementary carboxylation reaction catalyzed by phosphoenolpyruvate carboxylase where minimal oxygenation occurs. Such plants are known as C4 plants because the first products of CO2 fixation are carboxylic acids (oxaloacetic acid and malic acid) containing four carbon atoms.
Is C2 cycle photorespiration?
Mechanism of photorespiration /C2 cycle: The process of photorespiration at the initial stage occurs inside the chloroplast. Its primary substrate is an early product of photosynthesis, the glycolate. Since glycolate is a 2-carbon compound the process is also termed as C2 cycle.
What is true photorespiration?
Photorespiration is a process in plants in which occurs when the carbon dioxide concentration drops to a low level. Photorespiration results in a loss of carbohydrate production for plants.
Which condition is for photorespiration?
Photorespiration is favoured by the high oxygen and low carbon dioxide conditions.
Which of the following is formed during photorespiration?
Photorespiration wastes energy and steals carbon Two molecules are produced: a three-carbon compound, 3-PGA, and a two-carbon compound, phosphoglycolate.
What is the difference between respiration and photorespiration?
Hint: Respiration is the process in which intake of oxygen and release of carbon dioxide happen and photorespiration is the process in which the enzyme RuBisCo oxygenates RuBP by wasting the energy produced by photosynthesis….
| Respiration | Photorespiration |
|---|---|
| It is a catabolic process. | It is also a catabolic process. |
Why is Calvin cycle called C3 cycle?
The most common set of carbon fixation reactions is found in C3-type plants, which are so named because the major stable intermediate is the 3-carbon molecule, glyceraldehyde-3-phosphate. These reactions, best known as the Calvin cycle (Figure 6.2.