256 LEAVES 



E. 13. Contrast large leaves with small leaves as to advantages 

 and disadvantages. 14. State the advantage and disadvantage of 

 large and small foliage area, indicating what limits the amount 

 thereof. 



Suggested Study. — Select some common weed which is famUiar 

 to you and write a description of what seem to you the particularly 

 advantageous features of its roots, stems, and leaves. 



Section 56. A. i. Define transpiration and explain why it is 

 not a function. 2. State the disadvantages of transpiration. 3. State 

 the advantages of transpiration. 4. Explain how transpiration may 

 be an advantage at one time and a disadvantage at another. 



B. 5. Describe the general relation of water to the plant, making 

 a comparison with animals, and stating its threefold use to plants. 



C. 6. Define respiration. 7. To what extent are leaves like 

 lungs ? 8. Explain the difference between respiration and breathing. 



9. Explain how air reaches parts of plants that are under water. 



10. State similarities and differences between respiration and burning. 



D. II. Name the three principal classes of food, and distinguish 

 between them as to how and where they are made. 12. Name the 

 materials out of which carbohydrates are made, and state the source 

 of each. Are these materials' organic or inorganic ? 13. What is 

 the basis of the classification of food into the three classes indicated ? 

 14. Discuss the physical properties of sugar and starch as related to 

 movement through the plant body. 15. Discuss the composition -of 

 the molecules of carbohydrates. 16. Explain why the belief arose 

 that the breathing of plants is the reverse of that in animals. 17. Dis- 

 tinguish between the functions of chlorophyll and protoplasm in ' 

 photosynthesis. 18. State the use of the mineral solutes which enter 

 the plant, and give an example of a mineral and its use. 19. Describe 

 the first observable product of photosynthesis. 20. Describe an 

 experiment to show that an illuminated part of a leaf will 

 produce starch while a darkened part will not. 21. Define photo- 

 synthesis. 



E. 22. Give a sumniary as to the gaseous exchanges of the plant. 

 Section 57. A. i. Describe the structure and function of the 



epidermis of a leaf. 



B. 2. Describe stomates and guard-cells. 3. Describe the action 

 of guard-cells in opening and closing the stomates, defining turgid 



