PHOTOSYNTHESIS AND RESPIRATION. 103 



before and after leaving a green plant within it ? State the relative 

 quantity of the various gases, and how the presence of each can be 

 detected. Explain briefly how you would attempt to measure the 

 quantity of each gas present in the mixture. 



21. Bubbles of gas arise when a green water-plant in a bowl of 

 ordinary tap-water is placed in sunlight. What is this gas, and how 

 is it produced ? Give as full an explanation as you can of the effect of 

 (a) replacing the tap- water by previously boiled water ; (6) intro- 

 ducing lumps of ice into the original bowl of water. 



22. What process is meant by the term Photosynthesis? State as 

 briefly as possible the conditions necessary for such a process. Describe 

 accurately an experiment you have seen which demonstrated that 

 a plant was carrying on the process. 



23. Describe any experiments which throw light on (a) the passage 

 of fluids through membranes by osmosis, (6) the passage of gases by 

 diffusion through small openings. What have these experiments to do 

 with plant life ? 



24. Describe as many experiments as possible showing the effect of 

 temperature on the physiological processes of plants. 



25. Sketch a course of work on a green leaf for an elementary class 

 which is not provided with microscopes. 



26. Describe the minute structure of a small bit of a green leaf. 

 Show that it is specially fitted for absorbing and liberating certain 



27. A seed (e.g. a Bean) is germinated in a dark cupboard. Describe 

 the seedling plant developed under these conditions, arid point out 

 in what respects it differs from a plant grown in the light. 



28. How would you obtain, and prepare for examination, living, 

 under the microscope, the green cells of a foliage-leaf ? Draw carefully, 

 and describe in detail, the structure of such a cell, naming the different 

 parts, and mentioning, so far as you can, their uses. 



29. What conditions are essential in order that a green leaf may 

 form starch ? Give an account of the experimental evidence on which 

 your answer is based. 



30. Explain as fully as you can the reasons for the lanky appear- 

 ance exhibited by many plants when grown in the shade of trees. 



31. To what substance do the green parts of plants owe their colour, 

 and what is the use of this substance to the plant ? 



32. What is meant by respiration in plants ? Describe any anatomical 

 features in one of the higher plants which are suited to facilitate the 

 respiratory processes. 



33. How would you identify the gases of which the atmosphere is 

 composed ? Do you know how to determine the proportion by volume 

 in which the two principal gases exist? Which of the gases of the 



