BIOL 120A Chapter 4: Chapter 4 Detailed Notes
Document Summary
The loss of water vapor from leaves is the force behind the movement of water in xylem. The casparian strip is a layer of suberin on the radial and transverse that prevents the apoplastic movement of water into the stele. Once water is in the xylem of the stele its movement upward in the plant is driven by the pull of transpiration as well as some properties of the water molecule itself, cohesion and adhesion. As transpiration occurs in the leaf it creates a cohesive pull on the whole water column downward from the leaf through the xylem to the root and water uptake occurs to replace the water lost through transpiration. Metabolism is the sum total of all chemical reactions occurring in living organisms. Metabolic reactions that synthesize compounds are referred to as anabolic reactions. Energy is defined by physicists as the ability to do work and is governed by certain physical principles.
