Advertisements
Advertisements
प्रश्न
How would you demonstrate that green plants release oxygen when exposed to light?
Advertisements
उत्तर
- Place some water plants (Elodea or Hydrilla) in a beaker containing pond water and cover them by a short-stemmed funnel.
- Invert a test tube full of water over the stem of the funnel. (Ensure that the level of water in the beaker is above the level of the stem of the inverted funnel.)
- Place the apparatus in the sun for a few hours (in Fig). Bubbles of the gas will collect in the test tube.
- Test the gas in the test tube. A glowing splinter bursts into flame, which shows the presence of oxygen.
संबंधित प्रश्न
The diagram alongside refers to an experiment in which the apparatus was set up with the light source 10 cm away from the plant. After 15 minutes the number of bubbles evolved per minute from the cut stem was recorded. The light source was moved to 20 cm away from the plant, left for 15 minutes and the number of bubbles evolved per minute was again recorded. The experiment was repeated with the light source at distances of 40, 60, 80 and 100 cm away from the plant. Plot a graph for the results obtained and answer the following questions.
(i) From the graph it seems likely that the rate of bubbling per minute at 50 cm would have been
(a) 2.0 (b) 2.5 (c) 3.0 (d) 3.5
(ii) The gas produced by the plant during the experiment was
(a) air (b) oxygen (c) carbon dioxide (d) nitrogen (e) hydrogen
(iii) The gas collected comes due to the breakdown of
(a) glucose (b) starch (c) water (d) air (e) ATP
(iv) If ice cubes were added to the water, the rate of bubble formation would
(a) Stay the same.
(b) Increase because more water is added.
(c) Decrease because the temperature drops.
(d) Decrease because water freezes.
(e) Cannot tell from the information given.
(v) If some sodium bicarbonate is added to the water the rate of bubble formation
(a) Increases because more respiration occurs.
(b) Increases because more photosynthesis occurs.
(c) Increases because the gas becomes less soluble.
(d) Decreases because carbon dioxide acts as a limiting factor.
(e) Decreases because respiration decreases.
How do non-green plants such as fungi and bacteria obtain their nourishment?
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.
Name any one organism that could be shown at No .5
Given alongside is the diagram of an experimental set-up:
- What is the objective of this experiment?
- Will it work satisfactorily? Give reason.
- What alteration(s) will you make in it for obtaining expected result?
- Would you take any steps before starting the experiment? Describe this step and explain its necessity.
Given alongside is the diagram of an experimental set-up:
What alteration (s) will you make in it for obtaining expected result?
Where are the chlorophyll pigments present in a cell?
Differentiate Between:
Light reaction and Dark reaction.
Name the following:
The green colouring matter of the plants.
Complete the following sentence with appropriate word:
Carbon dioxide enters the leaf through _______.
