Exam 2

Question 1

How can plants absorb water?

Answer 1

roots, leaves, and as vapor through pores

Question 2

Properties of water that allow transport within a plant

Answer 2

cohesion, adhesion, surface tension

Question 3

How can cells alter their solute potential?

Answer 3

• active transport of solutes across the membrane
• break down reserved starches into glucose

Question 4

When does the radius of curvature decrease?

Answer 4

when water recedes into cell wall spaces

Question 5

Osmosis

Answer 5

movement of water across a selectively permeable membrane

Question 6

Solute potential is also known as…

Answer 6

osmotic potential

Question 7

Pressure potential is usually positive in ______ and negative in __________.

Answer 7

positive in cells and negative in xylem

Question 8

Tracheids

Answer 8

• long, slender xylem
• lateral movement of water through pit pairs

Question 9

vessel elements

Answer 9

• short, wide xylem
• vertical movement of water through sieve plates

Question 10

guttation

Answer 10

when pressure builds in the roots and sap is pushed up through the plant to the leaves, where it escapes through pores

Question 11

hylathodes

Answer 11

pores present along leaf margins that don’t have guard cells

Question 12

cohesion-tension theory

Answer 12

negative pressure develops in the leaves as water evaporates, and that tension pulls water through the xylem

Question 13

apoplastic pathway

Answer 13

water travels through the root cortex to the xylem via the apoplastic space, never entering cells

Question 14

symplastic pathway

Answer 14

water travels through the root cortex by going cell to cell via plasmodesmata

Question 15

endodermis

Answer 15

protective layer of cells around the vascular tissue with selectively permeable membranes

Question 16

casparian strip

Answer 16

lignin and suberin deposits that prevent apoplastic movement

Question 17

field capacity

Answer 17

the amount of water that soil can hold after it has been saturated and drained (-0.03 MPa)

Question 18

permanent wilting point

Answer 18

when water begins to bind so tightly to soil particles that it is no longer accessible to plants (-1.5 MPa)

Question 19

plant available water

Answer 19

the range between field capacity and permanent wilting point where plants can access water without the soil being saturated

Question 20

formula for water potential

Answer 20

Ψ water = Ψ solute + Ψ pressure + Ψ gravity

Question 21

formula for solute potential

Answer 21

Ψ solute = -RTc (
R = gas constant
T = temp
c = concentration

Question 22

formula for negative pressure caused by water adhesion to cell walls

Answer 22

P = -2Tcos(a) / r
r = radius of curvature
T = surface tension

Question 23

formula for water vapor potential

Answer 23

Ψ wv = 0.46 x T x ln [%RH/100]
T = temp

Question 24

cytoplasmic sleeve

Answer 24

extension of cytoplasm from one cell to another

Question 25

mass exclusion limit

Answer 25

large proteins and sugars cannot travel symplastically

Question 26

cytoplasmic streaming

Answer 26

coordinated movement of various components within the cytosol

Question 27

microtubules

Answer 27

polymers of tubulin

Question 28

microfilaments

Answer 28

polymers of actin

Question 29

myosins

Answer 29

allow movement on microfilaments

Question 30

kinesins

Answer 30

allow movement on microtubules

Question 31

motor proteins

Answer 31

one end binds to the cytoskeleton, and the other to a vesicle for transport

Question 32

soil-plant-atmosphere contimuum

Answer 32

water moves from soil to plant to atmosphere