5 Written questions
5 Matching questions
- Explain how elasticity can be different in plants with different functional needs
- Sum up the importance of water potential:
- Why doesn't water boil under the tension created during transport in the xylem?
- What is an exodermis?
- What is the driving force of water loss through the leaf?
- a the cohesion and adhesion properties of water make the liquid to vapor activation high in water, within the xylem the energy is not available to under go the change
- b the absolute concentration difference (moles/cubic meters) this is effected by temperatures
- c a layer on the outside of the epidermis that is not water permeable
- d in plants with very elastic cell walls there can be a change in water potential resulting in a large change in water volume, they can swell with increased water availability.
- e to maintain positive tugor pressure to increase the mechanical rigidity of the cells and tissues allowing for cell growth via the stretching of cell walls
5 Multiple choice questions
- it is influenced by both diffusion and bulk flow and driven by water potential gradients. It occurs spontaneously with these forces.
- it is the relative expression of the free energy associated with water, it is the difference between the potential as a given state and the potential of substance at a standard state
- 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
- this is driven by a gradient in water vapor concentration
- this is the energy required to go from liquid to vapor. This can help to cool the plant, allowing it to lose heat when it gets to hot.
5 True/False questions
What can reduce tensile strength in a water column? → this is driven by a gradient in water vapor concentration
Symplast: → 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
What 3 different pathways does water move through? → apoplast, symplast and transmembrane
What is soil hydraulic conductivity? → the ease at which the water moves through the soil (remember spaces between soil particles)
What is surface tension? and why is this important in water? → it is the energy used to increase the surface area, the amount of surface area occupied by the interface of air and water. this is important because remember that water is more attracted to itself then to air molecules. (This is what can create contact angels) water generally wants to minimize the surface area at the air water interface