13 - Plant Transport Flashcards
How do roots take up all of the ions that are in the soild? the plant is hypertonic to the soil so there is a concentration gradient
specifically creates a charge gradient, the plant activel exports H+ nions from the cell via an ATP pump, there fore causeing the intracellular charge of the cell to become electronegative drawing in cations through diffusion throught the transmb channel
how do roots uptake negatively charged molecules like NO3-
through an H+ cotransporter the NO3- goes up its concentration gradient, as wll as large molecules like sugar + H+
Why does H2O move through the plant?
during the day?
Night?
negative pressure during the day b/c of evaporation
night = ionic concentration in root cells = osmotic pull
7 - epidermis
8 - cortex
9 - endodermis
10 - parenchyma
11 - phloem
12 - Xylem
13 - pith
How is the arrangement of vascular tissue different in monocot and dicot stems?
In monocots, vascular bundles are scattered throughout the ground tissue, with many at the periphery and decreasing numbers toward the center of the stem. By contrast, the vascular bundles in dicots are arranged in a single ring toward the periphery of the stem, with none in the center.
How is the arrangement of vascular tissues in a monocot root different from a dicot root?
In monocots, the vascular bundle has a central pith, which is surrounded by a cylinder of xylem, surrounded by a cylinder of phloem. By contrast in the vascular bundle of a dicot the xylem is a star-shaped, centrally located column with strands of phloem located between the arms or points of the xylem.
Potatoes contain food in the form of starch, which ground tissue are you eating when you eat mashed potatoes?
parenchyma
The part of rhubarb that people eat is the petiole of a large leaf. Which tissue provides support for rhubarb?
collenchyma
Which ground tissue is a major component of the blades of spinach leaves?
parenchyma
Which ground tissue makes the shell of a nut hard?
sclerenchyma
The _____________ prevents substances from leaking back out of teh xylem
casperian strip
describe the casperian strip
waxy
impenitrable via transmb route or apoplastic route
acts as a guard for the roots
list the three routes that water and minerals get into roots, which one is the most direct
- apoplastic - through the cellular walls - doesn’t get direct access
- symplastic - through the plasmodesmata - direct route
- transmembrane - accross cells - not direct
The ___________ route gains minerals and water entry though the casparian strip via ___________
symplastic
plasmodesmata
Why doesnt the plant have its casparian strip just inside of the pidermis versus the endodermis?
it increases the surface area of absorption
How does the concentration of potassium affect guard cells?
- stomata opening and closing as the ions enter and leave the stomata bring along with it H2O.
- the movement of the K+ ions brings with it water, and is caused by light changes
- this is under hormonal control
Define transpiration
- water evaporation via xylem cohesion and adhesion to the polar cllulose of the walls of the X
- also keeps the temp regulated of the plant
where are the sinks of the plant?
growing things -
also storage for excess
Define translocation
movement in Phloem of sugars hormoes from sourse to sink
the bulk flow is facilitaed by positive pressure
Where is the source cell for sugar production
where chlorophyll is taking sunlight and turning it inot sugar
what is the difference b/t the mech of bulk transport oin xylem vs phloem?
X = negative pressure
P = positive pressure
A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This living cell would be a part of which structure?
Select one:
A. The root cortex
B. A guard cell
C. The root epidermis
D. The casparian strip
E. The endodermis
The endodermis
Which of the following is NOT part of the transpiration-cohesion-tension mechanism?
Select one:
A. Water is remarkably cohesive
B. Removal of water from the xylem exerts a pull on the water column
C. Water evaporates from the walls of mesophyll cells
D. The high pressure created by the K+ concentration gradient aids in the pull on the water column
The high pressure created by the K+ concentration gradient aids in the pull on the water column
Which statement about phloem transport is NOT true?
Select one:
A. Phloem sap flows due to pressure
B. The location of the source and sink can change
C. At the sink solute is always actively transported
D. At the sink water returns to the xylem
At the sink solute is always actively transported
