Question

Write a short note on flashing light experiment.

Answer 1

Sol:
I think this question is not covered in any of the chapter of any of the board syllabi.Anyway your answer is here.

Warburg performed some experiments on chlorella and expressed his results as amount of photosynthesis per total elapsed time.
*Warburg used sectors which cut out half the incident light in each revolution. So, time during which cells were illuminated was half of the elapsed time of the experiment. 
*At high intensity of light and high amount of carbon dioxide concentration, he found that a given amount of light reduced more carbon dioxide when allowed to fall on the cells intermittently than when allowed to fall on the cells continuously. 
*The improvement in the yield of the intermittent over the yield in continuous light depended on the frequency of flashing. 
*He concluded that reduction of carbon dioxide continues in the dark or it is faster during the flash light. This indicates that after a period of darkness, a flash of bright light will increase the concentration of reacting substances for the dark reaction to continue. But this does not happen in continuous exposure to bright light. 

hope it helps plz mark as brainliest

Answer 2

Answer:

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Write a short note on flashing light experiment.

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Flashing (Intermittent) Light Experiment

• It was performed by Warburg. He established that the rate of photosynthesis was found to be greater in intermittent light as compared to continuous light. It indicates the existence of two steps in photosynthesis, a light dependent reaction and another light independent reaction (the dark reaction enzymatic reaction).

• Both red and blue light are equally effective in photosynthesis but red light is more efficient. For biosynthesis of chlorophyll, raw material required are succinyl Co-A and glycine.
• CRASSULACEAN ACID METABOLISM (CAM) (Diurnal acid cycle):

1. Certain plants called CAM plants (with Crassulacean Acid Metabolism - CAM) have scotoactive stomata. These plants fix CO, during night but form sugars only during day (when RuBisCO is active e.g., Sedum, Kalanchoe, Pineapple. Opuntia
2. CO₂ is fixed during night (dark) to OAA using PEP carboxylase. This CO₂ comes from respiration (breakdown of starch) and also from the atmosphere. Malic acid gets stored in vacuoles.

• The CAM plants also contain the enzymes of Calvin cycle. During day time, malic acid breaks into pyruvate and CO... While CO, enters the Calvin cycle, pyruvate is used up to regenerate PEP.
• The succulents, therefore synthesize plenty of organic acids from CO, during night (when stomata are open) and plenty of carbohydrates during the day (when stomata are closed).
• Like Calvin cycle, CAM cycle also operates in the mesophyll cell. None of these have shown chloroplast dimorphism as is found in C, plants.

• It should be remembered that the slow growing desert succulents exhibiting CAM cycle have the slowest photosynthetic rate, while the species possessing C, pathway possess the highest rates.
• Thus, CAM plants are although not as efficient as C, plants, they are definitely better suited to the adverse conditions (ie., conditions of extreme desiccation).

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Photorespiration is not related to aerobic respiration as aerobic respiration occurs throughout the day and night in all types of cells, but photorespiration occurs in presence of light in green cells only. ATP is produced in aerobic respiration unlike photorespiration where ATP is consumed. Photorespiration utilizes a part of light energy and saves the plant from photo-oxidative damage.

The minimum temperature at which most plants starts photosynthesis is 0-5°C. It is as low as - 35°C for gymnosperms. Maximum temperature at which photosynthesis can occur is 50-55°C for desert plants and 70-75°C for hot spring algae.

Oxygenic photosynthesis: In green plants and cyanobacteria water is used as a source of reducing power. Photolysis of water results in release of oxygen as by-product. This photosynthesis which involves oxygen release is called oxygenic photosynthesis eg. BGA, diatoms dinoflagellates and green plants.

Anoxygenic photosynthesis: In bacteria evolution of oxygen during photosynthesis has not been demonstrated as they are incapable of using H₂O as reducing power. Instead it is obtained from H.S. thiosulphate etc. eg. Green and purple bacteria.