KEY CONCEPT The vascular system allows for the transport of water, minerals, and sugars.

1. KEY CONCEPTThe vascular system allows for the transport of water, minerals, and sugars.

2. Xylem contains specialized cells. vessel elements are short and wide tracheid cells are long and narrow xylem cells die at maturity tracheid vessel element Water and dissolved minerals move through xylem.

3. Plants passively transport water through the xylem. Cohesion is the tendency of water molecules to bond with each other. • The cohesion-tension theory explains water movement. • Adhesion is the tendency of water molecules to bond with other substances.

4. absorption occurs at roots • Water travels from roots to the top of trees. • cohesion and adhesion in xylem • transpiration at leaves

5. water vapor exits leaf stomata helps pull water to the top branches • Transpiration is the loss of water vapor through leaves.

6. Phloem contains specialized cells. sieve tube elements have holes at ends companion cells help sieve tube elements unlike xylem, phloem tissue is alive Phloem carries sugars from photosynthesis throughout the plant.

7. plants actively transport sugar from the source sugar flows to the sink due to pressure differences phloem xylem sugars Water moves from the xylem into the phloem by osmosis, due to the higher concentration of the sugars in the phloem. The water flow helps move sugars through the phloem. 2 Sugars move from their source, such as photosynthesizing leaves, into the phloem. 1 water The sugars move into the sink, such as root or fruit, where the are stored. 3 • The Pressure-flow model explains sugar movement.

8. Water moves through the plant’s roots in the xylem that • Acts like tiny pumps • Carry sugar to the roots • Have matured and died • Have no cell walls

9. The cohesion-tension theory proposes that water rises through plants because of • Metabolic energy expended by plants • The physical properties of water • Pressure changes between sources and sinks • Transpiration from roots

10. Water vapor escapes from plants by the process of • Capillary action • Transpiration • Cohesion • Adhesion

11. Phloem tissue is made up mainly of • Xylem cells and stomata • Dead cells and sugar sinks • Vessel elements and tracheids • Sieve tube elements and companion cells

12. What does the pressure-flow model explain? • How pressure is kept the same throughout a plant • How water moves through a plant • How sugars are produced by photosynthesis • How sugars move through a plant