Transport in plant

Question 1

bulk flow

Answer 1

the group movement of molecules in response to a difference in pressure between two location

Question 2

osmosis

Answer 2

the passive transport off water across a selectively permeable membrane in response to solute concentration gradients, a pressure gradient, or both

Question 3

water potential

Answer 3

the potential energy of water, representing the difference in free energy between pure water and water in cells and solutions, it is the driving force for osmosis

Question 4

megapascals (Mpa)

Answer 4

a unit of pressure used to measure the water potential

Question 5

solute potential

Answer 5

the effect of dissolved solutes on water potential ( the potential energy of water)

Question 6

pressure potential

Answer 6

the influence of physical pressure on water potential (the potential energy of water)

Question 7

turgor pressure

Answer 7

the internal hydrostatic pressure within plant cells

Question 8

turgid

Answer 8

osmotic condition of a plant cell when it contains sufficient water to press the plasma membrane against the cell wall and prevent further wall expansion

Question 9

flaccid

Answer 9

dropping or inelastic through lack of water

Question 10

wilting

Answer 10

the drooping of leaves and stems caused by a loss of turgor

Question 11

plasmolysis

Answer 11

condition due to outward osmotic movement of water , in which plant cells shrink so much that they retract from their walls

Question 12

symplast

Answer 12

the compartment represented by a plant’s living parts; collectively, the interior of cells

Question 13

symplastic pathway

Answer 13

the route taken by water that moves through the cytoplasm of plant cells (the symplast)

Question 14

apoplast

Answer 14

the compartment made up of plant cell walls and spaces between cells

Question 15

apoplastic pathway

Answer 15

the route followed by water moving through plant cell walls and intercellular spaces (the apoplast)

Question 16

transmembrane pathway

Answer 16

the path followed by water when it enters root cells by crossing the cells’ plasma membranes or enters cells through membrane aquaporins

Question 17

endodermis

Answer 17

the innermost layer of the root cortex; a selectively permeable barrier that helps control the movement of water and dissolved minerals into the stele

Question 18

Casparian strip

Answer 18

a thin, waxy impermeable band that seals abutting cell walls in roots, the strip helps control the type and amount of solutes that enter the stele by blocking the apoplastic pathway at the endodermis and forcing substances to pass through cells (the symplast)

Question 19

xylem sap

Answer 19

the plant vascular tissue that distributes water and nutrients

Question 20

transpiration

Answer 20

the evaporation of water from a plant, principally from the leaves

Question 21

cohension-tension theory of water transport

Answer 21

the mechanism that transports water upward from roots to shoot parts in the xylem of vascular plants; due to cohesion of water molecules, the evaporation (transpiration) of water from shoot parts such as leaves creates a continuous negative pressure (tension) that draws water upward from roots.

Question 22

root pressure

Answer 22

the pressure that develops in plant roots as the result of osmosis, forcing xylem sap upward and out through leaves

Question 23

guttation

Answer 23

the exudation (discharge) of water from leaves as a result of strong root pressure

Question 24

Crassulacean acid metabolism (CAM)

Answer 24

a biochemical variation of photosynthesis that was discovered in a member of the plant family Crassulacean. Carbon dioxide is taken up and stored during the night to allow the stomata to remain closed during the daytime, decreasing waterloss

Question 25

translocation

Answer 25

in vascular plants, the long-distance transport of substances by xylem and phloem

Question 26

phloem sap

Answer 26

the solution of water and organic compounds that flows rapidly through the sieve tubes of plants

Question 27

source

Answer 27

in plants, any region (such as a leaf) where organic substances are being loaded into the sieve tube system of phloem

Question 28

sink

Answer 28

any region of a plant where organic substances are being unloaded from the phloem and used or stored

Question 29

pressure flow mechanism

Answer 29

in vascular plants, pressure that builds up at the source end of a sieve tube system and pushes solutes by bulk flow towards a sink, where they are removed