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प्रश्न
How does the light-dependent reaction differ from the light-independent reaction? What are the end product and reactants in each? Where does each reaction occur within the chloroplast?
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उत्तर
Light-dependent photosynthesis is called Hill reaction or Light reaction. The Light independent reactions are called the Biosynthetic phase.
| Light-dependent reaction | Light independent reaction |
| 1. It is called Hill reaction or Light reaction. | 1. It is called the Dark reaction or Biosynthetic pathway or the Calvin cycle. |
| 2. The reaction is carried out in Thylakoid membranes (Grana) of the chloroplast. | 2. This reaction is carried out in the stroma of the chloroplast. |
| 3. Photosynthetic pigments absorb the light energy and convert it into chemical energy ATP and NADPH2. | 3. CO2 is reduced into carbohydrates with the help of light-generated ATP and NADPH2. |
| 4. It is carried out in the presence of light. | 4. It is carried out in the absence of light. |
In the light-dependent reaction, the chlorophyll absorbs the light energy and converts it into chemical energy ATP and NADPH2. In the light-independent reaction, CO2 is reduced into carbohydrates with the help of light-generated ATP and NADPH2. The light-dependent reaction is carried out in the Grana of the chloroplast. The Light independent reaction is carried out in the stroma of the chloroplast.
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संबंधित प्रश्न
Describe an experiment to prove that sunlight is necessary for photosynthesis.
A potted destarched plant was taken in order to prove that light is necessary for photosynthesis.
(i) What is meant by 'destarched plant'? How can it be destarched?
(ii) Using the destarched plant describe step by step how you would proceed to prove that in the absence of light the leaf cannot manufacture starch.
A leaf is a food factory. Explain.
On a bright sunny day, water weeds growing in an aquarium were actively giving off bubbles of gas. Use this information to answer questions that follow:
- Name the process occurring in the water weed that has resulted in the evolution of these bubbles.
- Of what gas do these bubbles consist?
- Briefly describe the reactions occurring in the leaves of the water weeds leading to the evolution of these bubbles.
- Give an overall balanced chemical equation to represent the process named in (i) above.
What is meant by a destarched plant? How can it be destarched?
A healthy croton plant bearing variegated leaves was kept in a dark cupboard to destarch it after which it was placed in sunlight for a few hours. One of the leaves was then plucked and an outline of the leaf marking the green and the non-green regions was drawn. The leaf was then tested for starch. Using the above information, answer the following questions:
- State the aim of the above experiment.
- Name the chemical used for testing the presence of starch.
- Why is the leaf boiled in water and alcohol before testing for the presence of starch?
- What change is seen on the leaf after the starch test?
- Give the chemical equation to represent the process of starch formation in plants.
A candidate in order to study the importance of certain factors in photosynthesis took a potted plant and kept it in the dark for over 24 hours. Then in the early hours of the morning, she covered one of the leaves with black paper in the center only. She placed the potted plant in the sunlight for a few hours, and then tested the leaf which was covered with black paper for starch.
- What aspect of photosynthesis was being investigated?
- Is there any control in this experiment? If so, state the same.
- Why was the plant kept in the dark before the experiment?
- Describe step by step how the candidate proceeded to test the leaf for the presence of starch.
Name the following:
In-plant cells, carbohydrates are stored in which form.
Name the following:
The chemical substance used to test the presence of starch in the cell of a leaf.
Define Photosynthesis.
State whether true or false. If false, correct the statement.
Photosynthesis produces glucose and carbon dioxide.
State whether true or false. If false, correct the statement.
Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
Write the reaction for photosynthesis?
The reactions of photosynthesis make up a biochemical pathway.
What is the end product of light and dark reactions of photosynthesis?
The reactions of photosynthesis make up a biochemical pathway.
Explain how the biochemical pathway of photosynthesis recycles many of its own reactions and identify the recycled reactants.
______ food is made in their green stems.
Expand the abbreviation - NADP.
Name four essentials for photosynthesis.
Write the exact location of palisade cells.
