What is the rate of photorespiration?
The rate of photorespiration (5.7 ± 0.3 mg CO2·dm−2·−1) during photosynthesis in 21% O2 at 25 C and 3,500 footcandles was over three times the rate of dark respiration and was independent of CO2 concentrations from 0 to 300 μl/l.
What are the factors that affects the rate of photorespiration?
Factors affecting photorespiration High temperature and high light intensity increase photorespiration remarkably. Photorespira- tion rate decreases linearly with the lowering of atmospheric 02 concentration because 02 is indispensable for producing glycolate in the process of photorespiration.
Does photorespiration slow photosynthesis?
C3 Photosynthetic Pathway One of the products of this reaction, 2-phosphoglycolate (PG) is further metabolized in the photorespiratory carbon oxidation cycle, which leads to the release of CO2 in the light, a process called photorespiration. Photorespiration reduces net photosynthesis in two ways.
How much energy does photorespiration release?
There is neither the synthesis sugar nor of ATP. Rather, it results in the release of CO2 with the utilisation of ATP. It leads to a 25 percent loss of the fixed CO2. So, photorespiration does not release energy.
Why photorespiration is high at high light intensity?
Photorespiration only occurs under high light intensities. It also requires high temperatures and high oxygen levels to occur. In C4 plants, the process does not occur. In C3 plants, if the intensity of light is high and O2 levels are high along with high temperature, photorespiration is likely to occur.
Why does photorespiration increase with temperature?
With the rising temperature, the solubility of CO2 decreases more rapidly than O2, so there is more O2 available, hence the rate of photorespiration increases.
What factors speed up or slow down the rate of photosynthesis?
Answer and Explanation: The environmental factors that speed up or slow down the rate of photosynthesis are temperature and the availability of sunlight and carbon dioxide. …
What increases the rate of photosynthesis?
If carbon dioxide and light levels are high, but temperature is low, increasing temperature will have the greatest effect on reaching a higher rate of photosynthesis.
Why does photorespiration decrease the efficiency of photosynthesis?
Photorespiration reduces the efficiency of photosynthesis for a couple of reasons. First, oxygen is added to carbon. In other words, the carbon is oxidized, which is the reverse of photosynthesis—the reduction of carbon to carbohydrate.
What is the percentage of energy loss during photorespiration?
It’s long been thought that more than 30 percent of the energy produced during photosynthesis is wasted in a process called photorespiration.
How does light intensity affect photorespiration?
Photorespiration rate increases at a higher temperature, lowered CO2 and higher O2 concentration. In C3 plants, if the intensity of light is high and O2 conc. is high along with high temperature, photorespiration rate increases.
Does photorespiration decrease in hot conditions?
Photorespiration is especially costly at high temperature because the oxygenation reaction is stimulated by high temperature more than is the carboxylation reaction.
Why do hot and dry conditions favor photorespiration?
Why do hot and dry conditions favor photorespiration? Because plants close their stomata, inhibiting CO2 uptake and increasing the O2 concentration in leaves. does not bind oxygen.
Why did the rate of photosynthesis decrease from 35 to 45?
This changes the shape of the active site for the enzymes, which means that the reactants can no longer fit into the enzyme’s active site, thus resulting in the rate of photosynthesis decreasing. The denaturing temperature depends on the type of plant but is usually around 35-45°C.
Which one of the following factors is most likely to limit the rate of photosynthesis at this time?
Three factors can limit the rate of photosynthesis: light intensity, carbon dioxide concentration and temperature.
How does photorespiration affect the rate of photosynthesis?
Why is photorespiration a wasteful reaction?
Biochemical studies indicate that photorespiration consumes ATP and NADPH, the high-energy molecules made by the light reactions. Thus, photorespiration is a wasteful process because it prevents plants from using their ATP and NADPH to synthesize carbohydrates.
Is energy consumed in photorespiration?
Photorespiration wastes energy and decreases sugar synthesis, so when rubisco initiates this pathway, it’s committing a serious molecular faux pas.
Does photorespiration occur at night?
Photorespiration is the respiration which occurs during the daytime.
Why is photorespiration more likely in warm weather?
Why is photorespiration more likely to occur during warm weather? a. The rubisco enzyme is very temperature sensitive and becomes less efficient in warmer temperatures, allowing it to fix O2 instead of CO2.