5 Written questions
5 Matching questions
- What is the pit membrane of the xylem and why is it important to water transfer?
- What constitutes your stomatal complex?
- In most plants as turgor pressure approaches zero what happens to the relative cell volume?
- What are aquaporins and why are they important in plants?
- If bulk flow is driven by pressure gradient how is it responsible for movement of water through soil?
- a it is decreased by about 5-10% (elasticity of the cell)
- b guard cells and subsidary cells found in the dumbell shaped guard cells of monocots
- c they are integral membrane proteins that form water selective channels. They are faster then travel through the lipid bilayer and can alter the rate of flow but not the direction (still passive). They can also be gated to allow for active regulation of water
- d pressure is created by water via curvatures, water is going to want to move to areas of larger spaces with smaller curvatures
- e this is a porous layer between the 2 pit pairs, made of 2 primary walls and a middle lamella. This membrane helps to prevent the spreading of gas bubbles within the xylem
5 Multiple choice questions
- water molecule attraction to a solid such as a cell wall or a glass tube
- surface tension, adhesion and cohesion. the capillarity of a liquid
- transfer of water traveling between cell walls and any extra cellular spaces that have water in it on it's way to the root cortex driven by hydrostatic pressure
- the ease at which the water moves through the soil (remember spaces between soil particles)
- difference in water vapor concentration in the air spaces in the leaf and the external air
5 True/False questions
Symplast: → pathway of water moving through a network of cells connected via the plasmodesmata going to the cortex driven by hydrostatic pressure
Diffusional resistance of transpirational pathway consists of what two components? → There are no metabolic pumps to drive water, it only occurs when water is coupled with ion (solutes) to carry it. This can occur because the loss of the free energy by the solute is greater then the gain of free E of the water. (negative net change in E is produced)
Sum up the importance of water potential: → the measurement of free energy of water per unit of volume. (J/m^3)
What are the 4 mechanisms and driving forces acting on water transport within the plant and between plant and the environment? → the absolute concentration difference (moles/cubic meters) this is effected by temperatures
What is the driving force of water loss through the leaf? → apoplast, symplast and transmembrane