Question

1. Where do gases enter plants? What gases are needed for photosynthesis? Which gas or gases exit a leaf? 2. How does water move up the xylem? What properties of water are involved in this transpiration process?

Answer 1

Explanation:

1. stomata

1 (a) Carbon dioxide enters stomata while water and oxygen exit, through a leaf's stomata they allow carbon dioxide in, but they also let precious water escape.

1 (b) Plants use carbon dioxide, oxygen and water in photosynthesis

2 Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem

2(a)Transpiration is the evaporation of water at the surfaces of the spongy mesophyll cells in leaves, followed by loss of water vapour through the stomata . Transpiration produces a tension or 'pull' on the water in the xylem vessels by the leaves. Water molecules are cohesive so water is pulled up through the plant