Sara placed a healthy potted plant in a dark room for 48 hours to perform an experiment on photosynthesis. She plucked one of the leaves and tested it for starch. The leaf did not turn blue-black on adding Iodine solution.
(a) Why was the plant placed in the dark for 48 hours?
(b) What is the significance of boiling the leaf in alcohol?
(a) The plant was kept in the dark to destarch it, so that its stored starch was used up during respiration.
(b) Boiling the leaf in alcohol removes chlorophyll, making the colour change with iodine clearly visible.
More ICSE Moderate level questions
Write the overall chemical equation for photosynthesis.
Expand the abbreviations: (a) NADP (b) ADP
Draw a neat, labelled diagram of a chloroplast.
Study the diagram given below and fill in the blanks with suitable words: In order to prove that carbon dioxide is necessary for (a) ............... , a potted plant is placed in dark for 48 hours to (b) ............... the leaves. A part of a leaf is inserted into a conical flask containing potassium hydroxide solution. This is to absorb (c) ............... from the flask. The plant is then placed in sunlight for a few hours. The experimental leaf is tested for starch. The part of the leaf that was inside the conical flask turns (d) ............... , whereas the part of the leaf outside turns (e) ............... in colour.
Name the following: (a) The fully developed part of the ovary containing a mature ovum. (b) A waxy layer on the upper epidermis of leaves meant to reduce Transpiration. (c) The ear ossicle which opens into the oval window of Cochlea. (d) The physiological process which is the starting point of all food chains. (e) An insect which is a classic example of natural selection due to industrial melanism.
A potted plant with variegated leaves was kept in dark for 24 hours and then placed in bright sunlight. Answer the following questions. (a) Which aspect of photosynthesis is being tested in the above diagram? (b) Why was the plant kept in dark for 24 hours? (c) After the starch test what will be the colour of the yellow and green parts of the leaf? Give reasons to support your answer.
The process of conversion of ADP to ATP during photosynthesis is called: (a) Photolysis (b) Phagocytosis (c) Photophosphorylation (d) Polymerisation
Write the overall chemical equation for photosynthesis.
The optimum temperature for photosynthesis is: (a) 10 – 15°C (b) 60 – 65°C (c) 40 – 45°C (d) 25 – 35°C
Draw a neat, labelled diagram to show that oxygen is released during photosynthesis.
Expand the abbreviation-NADP.
Write the overall chemical equation for photosynthesis
