Read This! The cuticle covering the upper and lower epidermis of land plants is made of a waxy substance that repels water in much the same way as wax on a paper cup. 14. What is the purpose of having a water-tight covering? The waxy cuticle keeps the water inside then is later used for photosynthesis. 15. Look carefully at the lower surface of the leaf in Model 2. a. What structure is found between guard cells? b. How would you describe this structure? c. How would this affect the ability of the leaf to retain water especially in dry conditions? 16. Suggest a way in which the stoma and guard cells arrangement might work to control the amount of water that is leaving the leaf. 17. What is the relationship between the stoma and an air space? Model 1, what gases might you find inside the air spaces? 19. During the time that stomata (the plural of stoma) are closed gases cannot enter or leave. Explain how this would affect the plant's ability to do photosynthesis. 20. In grammatically correct sentences, trace the path of the reactants for photosynthesis as they enter the leaf. 21.In grammatically correct sentences, trace the path of the products of photosynthesis as they exit the leaf.

14. The purpose of having a water-tight covering, such as the waxy cuticle on the surface of land plants, is to prevent excessive water loss from the plant. The cuticle acts as a barrier that repels water, helping the plant retain moisture and preventing dehydration, especially in dry conditions.<br /><br />15. a. The structure found between guard cells is called the stomatal pore or stoma.<br />b. The stomatal pore is a small opening surrounded by the guard cells.<br />c. The presence of the stomatal pore between the guard cells affects the leaf's ability to retain water by allowing the exchange of gases. When the stomatal pores are open, water vapor can escape from the leaf, leading to water loss. In dry conditions, the stomatal pores may close to minimize water loss.<br /><br />16. The stoma and guard cells arrangement work together to control the amount of water leaving the leaf by regulating the opening and closing of the stomatal pores. When the stomatal pores are open, water vapor can escape from the leaf, leading to water loss. Conversely, when the stomatal pores are closed, water loss is minimized, helping the leaf retain moisture.<br /><br />17. The relationship between the stoma and an air space is that the stoma is an opening surrounded by guard cells, while the air space is the space between the cells of the leaf. Gases such as carbon dioxide, oxygen, and water vapor can be found inside the air spaces.<br /><br />19. When stomata are closed, gases cannot enter or leave the leaf. This would affect the plant's ability to do photosynthesis because carbon dioxide, which is essential for photosynthesis, cannot enter the leaf. Additionally, oxygen, a byproduct of photosynthesis, cannot be released from the leaf.<br /><br />20. The reactants for photosynthesis, carbon dioxide and water, enter the leaf through the stomata. Carbon dioxide diffuses into the air spaces of the leaf, while water is absorbed by the roots and transported to the leaf through the xylem vessels.<br /><br />21. The products of photosynthesis, glucose and oxygen, are produced in the chloroplasts of the leaf cells. Glucose is transported out of the leaf through the phloem vessels, while oxygen is released into the air spaces and diffuses out of the leaf through the stomata.