Xylem Cells?

Question

On my biology homework, one of the questions state, "Account for the movement of liquids through xylem cells." There is nothing that leads up to the question or that could help me out. I would really appreciate it if somebody would answer this for me or at least explain the question in different words. Thank-you.

Answer 1

Water transported up from the roots must replace water lost by transpiration.

WATER POTENTIAL: Xylem sap rises against gravity, driven by a gradient of water potential. Water flows from an area of high potential to an area of low potential.
ROOT PRESSURE: When transpiration is low, ions pumped into the stele decrease water potential and cause water uptake by the stele. This uptake force is called root pressure. It Cannot keep pace with transpiration, and can only force water up a few meters.

TRANSPIRATION-COHESION-ADHESION THEORY:

a). water exits leaf through stomata.
b). this water loss is replaced by evaporation from mesophyll cells, lowering their water potential, causing them to take water from neighboring cells.
c). the process connects back to the tracheids causing water to be taken from the xylem.
d).Water travels from the tracheids to the air following a water potential gradient.
e). Waters cohesive and adhesive properties and the small diameter of xylem aid in its movement of up the tube.
f). This pull decreases water pressure in the xylem causing the roots to take water from the soil.

Answer 2

The question asks how water is transported through the xylem. Transpiration at the leaves pulls the water up from the root. When there is little transpiration, root pressure become more important. The major for water movement in the xylem is transpiration.

Answer 3

It is in the root and stalk and leaves of a plant, it transplants water throughout hte plant. The cells die and lose the upper and lower part of the cell wall, giving a tube. The cell wall is then hardened to support the water transfer. The xylem is now just the cell wall. In the root of a plant it is in the center and is in the shape of a cross. In the stalk it is towards the outer side of the plant and is on the inside to the phloem. In the leaves, it is in the vains and is on top of the phloem. The phloem is the tube that carries nutrients to the plant's leaves.

Answer 4

when in doubt ask wikipedia (but always check their references!!)

http://en.wikipedia.org/wiki/Xylem

Answer 5

PASSIVE TRANSPORT

they give a vague description, and YOU SHOOT ONE RIGHT BACK AT THEM. show them b*tches what you made of...