5 Written questions
5 Matching questions
- Explain water transport against gradients in plants:
- What is an exodermis?
- Water movement through soil is driven via what?
- What properties of water generates the physical forces to pull water up through the plant?
- a a layer on the outside of the epidermis that is not water permeable
- b 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)
- c surfaces tension and adhesion at the evaporative surfaces of leaves
- d pathway of water moving through a network of cells connected via the plasmodesmata going to the cortex driven by hydrostatic pressure
- e bulk flow
5 Multiple choice questions
- water molecule attraction to a solid such as a cell wall or a glass tube
- it is pulled up from the roots via a negative hydrostatic pressure
- difference in water vapor concentration in the air spaces in the leaf and the external air
- pathway of water into one cell from another cell, cell to cell only pathway to cross the cell membrane driven by water potential gradient
5 True/False questions
Explain how water in soil depends on soil type and structure → difference in water vapor concentration in the air spaces in the leaf and the external air
Water has a high laten heat of vaporization. What is this and why is it important for plants? → 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
What is the driving force of water loss through the leaf? → the absolute concentration difference (moles/cubic meters) this is effected by temperatures
Fisk's first law: → diffusion rate is directly proportional to the concentration gradient
What main things effect water potential? → type of median, the begging state of the cell (flaccid or turgid), and the pressure