Biology
The figure given below represents an experimental set up with a weighing machine to demonstrate a particular process in plants. The experimental set up was placed in bright sunlight. Study the diagram and answer the following questions.
(a) Name the process intended for study.
(b) Define the above mentioned process.
(c) When the weight of the test tubes A and B is taken before and after the experiment, what change is observed? Justify.
(d) What is the purpose of keeping the test tube B in the experimental setup?
(e) What is the purpose of putting oil in the test tube?
Answer
(a) Transpiration
(b) Transpiration is a process by which water is lost in the form of water vapour from aerial parts of the plant.
(c) Weight of test tube A before the experiment was more than its weight after the experiment. This is because water from test tube A has evaporated due to transpiration.
Weight of test tube B remains the same before and after the experiment, because no loss of water occurs in test tube B.
(d) Test tube B is used here as a control. This makes the observation of the change in test tube A easy.
(e) The purpose of putting oil in the test tube is to prevent loss of water from the test tube by evaporation.
Related Questions
An apparatus as shown below was set up to investigate a physiological process in plants. The setup was kept in sunlight for two hours. Droplets of water were then seen inside the bell jar. Answer the questions that follow:
(a) Name the process being studied.
(b) Explain the process named above in (a).
(c) Why was the pot covered with a plastic sheet?
(d) Suggest a suitable control for this experiment.
(e) Mention two ways in which this process is beneficial to plants.
(f) List three adaptations in plants to reduce the above mentioned process.
Given below is the figure of a stoma. Study the same and answer the following questions:
(a) Label the guidelines A and B.
(b) Write the exact location of the above mentioned structures.
(c) Mention one important role of structure A.
(d) Write three important roles of structure B.
(e) Redraw the same figure when structures A are in flaccid condition. When does flaccid condition occur ?
Given ahead is the diagram of an experimental set up to study the process of transpiration in plants. Study the same and then answer the questions that follow:
(a) Name the colour of dry cobalt chloride paper.
(b) Is the experimental leaf a monocot or a dicot? Give a reason to support your answer.
(c) Why are glass slides placed over the dry cobalt chloride papers?
(d) After about half an hour what change, if any, would you expect to find in the cobalt chloride paper placed on the dorsal and ventral sides of the leaf? Give a reason to support your answer.
An outline sketch of a tree is shown in a diagram below. Study the same and answer the questions that follow:
(a) Name and define the phenomenon labelled A in the diagram.
(b) Write the significance of the process mentioned in A for the plants.
(c) What do the direction of arrows in B and C indicate? Name the phenomenon.
(d) Draw a neat and labelled diagram of an opened stomata.