MCB 259: PLANT PHYSIOLOGY 1998, Quiz 3
According to van't Hoff's law the magnitude of the osmotic pressure is
a) proportional to the solute concentration
b) proportional to the inverse of the solute concentration
c) equal to the inverse of the temperature
A) the vacuole fuses with the cytosol,
B) the plasmalemma is destroyed,
C) the plasmalemma detaches from the cell wall
The waterpotential in the vacuole of a visibly plasmolyzed cell is eaqual to
Traube's cells come into existence and grow, if you place a crystal of a Cu2+ salt in a solution of K4[Fe(CN)6]. The membranes of these artificial cells are permeable/impermeable (circle the correct alternative) to water, but permeable/impermeable to Cu2+.
What causes the water uptake into Traube's cells?
a)turgor pressure, b)osmosis, c)matrix potential, d) all of the above?
What is the turgor pressure of the plant cell?
A) The difference between the hydrostatic pressure inside the cell and outside.
B) The tension of the cell wall minus the osmotic pressure.
C) the water potential of a plant cell surrounded by distilled water.
A fully turgescent cell with a 1 M concentration of osmotically active substances is transferred from destilled water into a 1 M solution of sucrose.
How high are the highest trees? (approx., circle correct answer)
approx.: 30m; 50m; 100m; 250m; 500m; 1000m; 2500m; 5000m
The endodermis is
Where on the way from soil => root => stem => leaves => gas phase inside the leaves => boudary layer => air surrounding the plant usually is the greatest drop in water potential? Circle region with highest drop.
Water flows (if it flows at all)
from places with positive to places of negative water potential (correct/incorrect)
from places with negative to places with more negative water potential (correct/incorrect)
always to places with a more positive water potential (correct/incorrect)
The main force that drives the flow of water through the plant is generated by
A) transpiration of water from the leaf cell wall which generates a tension (negative pressure) in that pulls up a continuous water column through xylem and root
B) osmotic water influx into the apoplast of the cells inside the endodermis which generates the root pressure
C) peristaltic movements of the stem
D) primary active water transport.
Why is in Renner's experiment a branch with leaves more effective in pulling water through a constricted piece of wood than a vacuum pump?
The permanent wilting point of most plants is reached at a soil water potential
A) of about -15 MPa, B) of about -13 bar, C) of about -130 bar, D) of about -1.5 MPa
E) less (more negative) than -100 bar
The outermost layer of a young root (with root hairs and before the onset of secondary thickness growth) is called A) Pericycle, B) Endodermis, C) Rhizodermis, D) Epidermis.
The water holding (or field-) capacity is an important soil characteristic.
Which of the following air water interfaces can sustain a larger difference in hydrostatic pressure?