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Question
During photosynthesis, the oxygen in glucose comes from
Options
CO2
water
both CO2 and water
oxygen via air
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Solution
CO2
RELATED QUESTIONS
A potted plant was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours. One of the leaves was covered with black paper in the centre. The potted plant was then placed in sunlight for a few hours.
(i) What aspect of photosynthesis was being tested?
(ii) Why was the plant placed in the dark before beginning the experiment?
(iii) During the starch test, why was the leaf
(1) boiled in water
(2) boiled in methylated spirit
(iv) Write a balanced chemical equation to represent the process of photosynthesis.
(v) Draw a neat diagram of a chloroplast and label its parts.
Define the following:
Plant pigments
The figure given below represents the vertical section of a leaf.
( i) Name the parts labeled 1 to 5.
( ii ) What do the two arrows (dotted and solid) indicate in the daytime and at night?
( iii) Could you add one more arrow in the figure? If yes, what for?
( iv) How many leaf veins have been shown in this section?

Complete the following by filling in the blanks numbered 1 to 10 with the appropriate word/term:
Photosynthesis involves light reaction and dark reaction. During light reaction, the chlorophyll present in the (1) ______ gets activated by absorbing light energy. This energy splits (2) ______ molecules to (3) ______ and oxygen and releases two electrons. This process is called (4) ______. The (5) ______ ions are picked up by NADP to form (6) ______. The ADP is converted to (7) ______. This process is called (8) ______. During the dark phase, the compound produced at the end of the light reaction reacts with carbon dioxide to form (9) ______. This product is converted to starch. The process is called (10) ______.
The diagram alongside represents an experiment conducted to prove the importance of a factor in photosynthesis.

Study the same and then answer the questions that follow:
(i) Name the factor being studied in his experiment.
(ii) Why was the plant kept in a dark room before conducting the experiment?
(iii}Why was the experimental leaf then kept in
1. boiling water 2. methylated spirit?
(iv) Name the solution used to test for the presence of starch in the leaf.
(v) What will we observe in the experimental leaf at the end of the starch test?
(vi) Give a balanced chemical equation to represent the process of photosynthesis.
Identify the false statement and rewrite it correctly by changing the first or last word only.
Green plants are consumers.
Draw a neat and well-labeled diagram of the apparatus you would set up to show that oxygen is given out during photosynthesis.
Mesophyll contains chlorophyll.
Read the following sentences about photosynthesis:
- Sunlight, carbon dioxide, chlorophyll and water are necessary.
- Oxygen is absorbed.
- Leaves carry out photosynthesis.
- Proteins are made during photosynthesis.
Choose the correct pair of sentences that are true to photosynthesis.
Sunflowers open the petals in bright light during the daytime but close the petals in dark at night. This response of sunflowers is called ______.
