Transport In Plants Flashcards
Function of phloem?
Transports sugars up or down the plant.
What is the apoplast pathway?
The pathway in which water passes through the spaces in the cell walls and between cells.
What is the symplast pathway?
Water enters the cytoplasm through the plasma membrane. Water then passes from cell to cell through the plasmodesmata.
What is the vacuolar pathway?
Water is not confined to cytoplasm but can also pass through vacuoles.
Best conditions for transpiration fast rate?
High light intensity
High temperature
Windy
High water availability in soil.
What will slow down the transpiration rate?
High humidity
Function of xylem?
Transports water and minerals up the plant.
What are the 3 water pathways?
The apoplast, symplast, vacuolar.
How does water move in the apoplast pathway?
By mass flow
What is the plasmodesmata?
The gaps in the cell walls containing cytoplasm that connects one cell to the next.
Which component of the plant cell is partially permeable?
The plasma membrane
What is transpiration?
The loss of water vapour from the aerial parts of the plant, mostly through the stomata in the leaves.
Why does transpiration occur mostly in the day.
The stomata is open for gaseous exchange for photosynthesis during the day
What is the first step of water leaving the leaf?
Water enters leaf through xylem. Moves by osmosis into cells of spongy mesophyll
What is the second step of water leaving the leaf.
Water evaporates from the cell walls of the spongy mesophyll
What is the third step of water leaving the leaf?
Water vapour diffuses through the open stomata.
Why is transpiration essential?
Transports essential minerals up the cell
Maintains cell turgidity
Supplies water for growth, cell elongation and photosynthesis.
Can cool down the plant in a hot day.
Structure of companion cell?
Many organelles particularly many mitochondria for energy for active transport. A companion cell for every sieve tube.
Why does high light intensity speed up transpiration rate?
Stomata are open to allow for gaseous exchange for photosynthesis.
Why do windy conditions speed up the rate of transportation.
Wind carries away water vapour that has diffused out the leaf. This maintains a higher water vapour potential in the leaf.
Why do high temperatures speed up the transpiration rate?
Increase the rate of evaporation from cell surfaces to increase water vapour potential in the leaf.
Increases rate of diffusion through the stomata as water molecules have more kinetic energy.
Maintains a low water potential in the air.
Explain the need for a transport system in multicellular plants.
Small surface area to volume ratio- diffusion would be too slow.
Demand for water and sugars is high- need a transport system to move water and minerals up to the leaves and sugars from the leaves from the rest of the plant. Unable to absorb water from the air and sugars from the roots.
What is the structure of Xylem.
Long tube like structures. No end walls between cells. Dead cells with no cytoplasm. - to allow more space for water. Supported my lignin which strengthens and waterproofs walls.
What are the vascular tissues
Phloem tissues and xylem tissues
What are dicotyledonous plants.
Those that have two seed leaves. The vascular tissue is distributed throughout the plant. The xylem and Phloem and found in vascular bundles.
Structure of phloem?
Contains sieve tubes and companion cells.
Structure of sieve tubes?
Joined end to end by sieve plates. Has pores to allow for ease of flow of solutes. Has no nucleus and thin cytoplasm.
Structure of a root cell?
Long tip, large surface area and lots of hairs.