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प्रश्न
(i) Draw a neat and well-labelled diagram of the Chloroplast.
(ii) List the events taking place in the photo-chemical phase of Photosynthesis.
(iii) If you are planning an experiment to show the effect of light on photosynthesis :
(a) Will you select white light or green light? Justify your answer.
(b) Why would you select a destarched plant?
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उत्तर
(ii) The photochemical phase of photosynthesis is light-dependent. A series of chemical reactions occur is quick succession initiated by light, therefore the phase is called photochemical phase. It takes place in chlorophyll-containing thylakoids of chloroplast.
It occurs in the following steps :
(a) The chlorophyll on exposure to light energy becomes activated by absorbing photons.
(b) This energy is used in splitting the water molecules (photolysis) as below :
H2O → H+ + OH–
(c) OH– ions through a series of steps produce water (H2O) and oxygen (O2). Water may be used inside the plant but O2 released into the atmosphere.
(d) H+ combines with CO2 in dark reaction to produce glucose.
(iii)
(a) I will select white light because photosynthesis is maximum in white light while it is minimum in green light as the green light is reflected by green plants.
(b) I will select the destarched plant so I can demonstrate the synthesis of starch through the iodine test.
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संबंधित प्रश्न
Choose the correct answer:
Which one of the following features of plant leaves plays an important part in photosynthesis?
The figure below represents an experiment performed to demonstrate a particular aspect of photosynthesis. The apparatus was kept in sunlight for almost the whole day. The numeral ‘1’ represents a certain condition inside the flask and the numeral ‘2’ represents a chemical responsible for this condition.
(i) What is the object of the experiment?
(ii) What is the special condition inside the flask?
(iii) What is the chemical substance numbered ‘2’?
(iv) In what way will the three leaves (A, B, and C) differ at the end of the experiment, when tested with iodine solution?
A well-watered healthy potted plant with variegated leaves was kept in darkness for about 24 hours. It was then set up as shown in the diagram and exposed to light for about 12 hours. At the end of this time, leaf X and leaf Y were tested for starch. Study the diagram and answer the questions that follow:
(i) Why was the plant initially kept in darkness for 24 hours?
(ii) What is the function of the sodium hydroxide solution in the flask?
(iii) Select the correct leaf from the five available choices shown in the diagram as A, B, C, D, and E. Rewrite the correct answer for the filling in the appropriate letter from the questions that follow:
1. After the starch test, leaf X would look like.
2. After the starch test, leaf Y would look like.
Explain the term Carbon cycle.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Too much light destroys chlorophyll.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
PhotoLysis is the reaction which means the breaking up of water molecules.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
The process of photosynthesis takes place in the dark.
Define the following term:
Thylakoids
Distinguish between the following pairs on the basis of the word indicated in the bracket ( ).
Stoma and Stroma (structure)
