Mas Transport In Plants Flashcards
What conditions affect water inside plants
Temperature
Light intensity
Humidity
Wind
What occurs to the stomata when the temperature is to high
Water gains kinetic energy
So evaporates at faster rate
What affect does humidity have on the opening of the stomata
Lots of water vapour
So WP m is formed and is greater outside
So reduces the m
What is meant by transpiration
Loss of water vapour from the stomata by evaporation
What happens when water vapour evaporates out of the stomata of leaves
Decreases the volume and pressure
What happens when transpiration occurs
Water potential gradient is formed.
More water if forced to replace it upwards
What happens to the roots when transpiration occurs
Volume of water increases
So does pressure
Why is the roots under negative pressure/tension
When water is pulled up the xylem/water column
Why can the water molecules stick together
Because they are bonded by hydrogen bonds
How is a column of water created in the xylem
When there is cohesion between the water molecules
Cause if the hydrogen bonds
What do the water molecules adhere to
Walls of the xylem
Why do the water molecules adhere to the xylem
Helps to pull water column upwards
Why does the xylem get narrow
When the water is pulled through the xylem
What is the xylem made up of
Dead cells
Lignin
Hollow
What is the role of translocation
The movement of sucrose and amino acids in a plant
Where is the sucrose made from during translocation
Respiration
What is found in the companion cell
H+ ions
What is the phloem made of
Sieve tube elements
Companion cells
What is an adaptation of companion cells
Have many mitochondria
Provides ATP for active transport
What are sieve tube elements made from
Living cells
No nucleus
Why also sieve tube elements have fewer organelles
For maximum flow
What is the movement of sucrose from the SOURCE into thé companion cell
High in source low in companion cell
Moves down gradient
Via facilitated diffusion into companion cell
What mode of transport does sucrose take from the source
Facilitated diffuse
Where is sucrose made
Photosynthesis
What is the movement of the hydrogen ions from the companion cell to the plasmodesmata
Active transport
Using ATP
Low concentration in companion cell compared to outside
What direction do the H+ ions move when they enter the plasmodesmata
Down concentration gradient
Via carrier protein
What allows the H+ ions to move from the plasmodesmata to the sieve tube elements
Carrier proteins
Where do we see the action of a Co transport protein
Sucrose and the H+ ion
Which transports sucrose into sieve tube elements
What allows the transport of of sucrose into the sieve tube elements
Co transport protein
What does an increase of sucrose in the sieve tube elements do to the water potential
Decreases
What decreases the water potential in the sieve tube
When there is an increase in sucrose
Where does the water come from when the water potential is reduced cause if the sucrose
Xylem vessels via osmosis
What does an increase in the water volume mean in the sieve tube elements
Increases the hydrostatic pressure
So it is forced down the sink
What does the high hydrostatic pressure do
Forces water down sink
What occurs in the sink cell
Respiration
What is the movement of sucrose when it wants to enter the sink cell
Active transport
What happens to the water potential when sucrose transports in via active transport
It decreases
A decrease in the water potential of the sink cell causes what happen
Movement of water via osmosis from sieve tube elements into sink cell
What happens when the volume decreases towards the sink cell
Hydrostatic pressure decreases
What encourages the movement of soluble organic substance to move
Difference in the hydrostatic pressure
