Chapter 11 (Transport in Plant) Flashcards
What is osmosis?
Movement of water from high water potential to low water potential across partially permeable membrane.
When does osmosis happen?
Osmosis happens when partially permeable membrane separates two solutions.
What is the name of an artificial partially permeable membrane?
Visking Tubing which has microscopic holes
Where is the visking tubing used?
In kidney dialysis machines
What is the relation between water concentration and water potential?
Directly proportional
Why water potential is low in sucrose solution?
Because water molecules are attracted to the sugar molecules.
What is water potential?
How free the water molecules are able to move.
Water in —– can move freely.
Pure water
The more concentrated solution, ——- the water potential.
Lower
Which keeps the shape of the cell?
Cell wall
What happens when cell absorb water?
The cell swells up, and becomes turgid.
What happens when the cell lost water?
The cell loosens up, and becomes flaccid.
What happens when a cell lost excessive water?
The membrane and cytoplasm split away from the cell wall, and become plasmolyzed.
What does the pressure inside the cell provide?
It supports the non-woody parts of a plant, such as leaves, and hold stems upright. so leaves can carry out photosynthesis properly.
Why is wilting protective action?
It cuts down water loss by reducing the exposed surface area of the leaves and closing the stoma.
Which increases the SA for root?
Root hairs
How does most water pass out of the leaves?
As water vapors
What is transpiration?
Loss of water vapor from the leaves.
What is the transpiration stream?
The flow of water from roots to leaves through xylem vessels in the plant.
What are the functions of the transpiration stream?
- Supplies water to the leaves cell for photosynthesis
- Carries mineral ions dissolved in the water
- Provide water to keep the plant cells turgid
- Allows evaporation from the leaf surface, which cools the leaf
Why do animal cells have low water potential?
Animals’ cells do not have strong walls to resist the changes in internal pressure caused by large movements of water.
What does xylem transport?
Water and mineral ions
What does xylem contain?
Xylem contains dead cells arranged end-to-end, forming a continuous vessels.
What happen to vessels when they become matured?
They contain no cytoplasm, instead they form a lumen which the water passes.
