Biology 1002 Section 3: Transport

apoplast

Everything external to the plasma membrane of a plant cell, including cell walls, intercellular spaces, and the space within dead structures such as xylem vessels and tracheids.

symplast

consists of the entire mass of cytosol of all the living cells in a plant, as well as the plasmodesmata, the cytoplasmic channels that interconnect them

apoplastic route

water and solutes move along the continuum of cell walls and extracellular spaces

Sympoplastic route

Move along the continuum of cytosol. Substances must cross a plasma membrane once, when they first enter the plant, then can move from cell to cell via plasmodesmata.

transmembrane route

water and solutes move out of one cell, across the cell wall, and into the neighboring cell

cotransport

Occurs when active transport of a solute indirectly drives transport of other substances. Plants use energy in H+ ion gradient.

opening and closing of stomata

In what process are K+ ions and K+ ion channels important?

bulk flow

The movement of a fluid due to a difference in pressure between two locations.

tracheids, vessel elements and sieve-tube elements

Long distance bulk flow occurs in which plant cells?

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

surface tension

the force that acts on the surface of a liquid and that tends to minimize the area of the surface

Transpiration

loss of water from a plant through its leaves and other aerial parts

Light, Co2 depletion, internal clock in guard cells

What 3 stimuli cause the opening of stomata at dawn?

Xerophytes

Plants adapted to arid climates are called _______

Casparian strip

waterproof strip that surrounds plant endodermis cells

hydrogen bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

cohesion-tension hypothesis

transpiration provides the pull for the ascent of xylem sap, and the cohesion of water molecules transmits this pull along the entire length of the xylem from shoots to roots

turgid

When guard cells are _______ the stomata pores open

flaccid

When guard cells are ________ the stomata pores close

circadian rhythm

the biological clock; regular bodily rhythms that occur on a 24-hour cycle

Translocation

the transport of organic nutrients in the phloem of vascular plants

phloem sap

The sugar-rich solution carried through a plant's sieve tubes.

Sugar source

an organ that is a net producer of sugar, such as mature leaves

sugar sink

A plant organ that is a net consumer or storer of sugar, such as growing roots, buds, stems, fruits.