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Flashcards in Plant Transport Deck (20)
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1
Q

Components of water potential

A

total potential = solute potential + pressure potential

2
Q

Movement of water

A

Passive movement toward more negative total water potential

3
Q

Hypotonic solution for plants

A

Turgid cell (normal)

4
Q

Isotonic solution for plants

A

Flaccid cell (limp)

5
Q

Hypertonic solution for plants

A

Plasmolyzed cell

6
Q

Solutes’ effect on potential

A

Negative effect

Binding of water molecules

7
Q

Positive pressure’s effect on potential

A

Positive effect

Pushing water

8
Q

Solutes’ and positive pressure’s effects on water movement

A

Opposing effects on water movement (net 0)

9
Q

Negative pressure (tension)’s effect on potential

A

Negative effect

Pulling water

10
Q

Movement of water into cell

A

Water goes into cell until cell potential=solution potential

11
Q

Passive transportation

A

No energy required
Movement from high to low concentration
Simple diffusion
Facilitated diffusion: channel (charged molecules) or carrier (binds specific molecule)

12
Q

Active transportation

A

Energy required
Movement from high to low concentration
Primary active: transport directly coupled to ATP
Secondary active: solute transported using potential energy from chemiosmosis (H+ gradient)

13
Q

Positive ions moving out of cell (membrane is positively charged)

A

Can be done if the concentration gradient is greater than the charge differential

14
Q

Structural aspects of stomata

A

Guard cells attached to each other at their ends

Radially oriented microfibrils- more support on inside of cell than outside

15
Q

Mechanism of water movement in stomata

A

Pumping K+ in or out of the guard cell changes solute potential and total potential
Osmosis due to potential differences
Guard cells swell or go limp, opening or closing stomata

16
Q

Short distance transport

A

Diffusion: 3 routes
Apoplastic route (non-living parts, within cell walls)
Symplastic route (living parts, within cytoplasm)
Transmembrane route

17
Q

Casparian strip

A

Links endodermal cells in plants

Prevents passage of cations and most solutes into endodermis

18
Q

Transport of sucrose in plant cells

A

Mesophyll cell -> bundle-sheath cell -> phloem parenchyma cell OR companion cell (through cell wall)-> sieve tube element -> phloem parenchyma cell
Sucrose is cotransported against its concentration gradient with H+ from the cell wall space into the sieve tube cell

19
Q

Transport of sucrose from source cell (leaf) to sink cell (root)

A

Loading of sugar from source cell (leaf) into sieve tube (phloem)
Uptake of water: osmosis from xylem (water pressure moves sucrose from high pressure to low pressure)
Unloading of sugar from sieve tube into sink cell (storage root)
Water recycled back into xylem

20
Q

Cohesion-tension theory

A

Long distance transport in xylem: water molecules cohere to each other and adhere to the xylem walls, overcoming gravity
Works by tension (negative pressure): much lower potential at top than at bottom
Too much tension: cavitation (air bubble)