Notes-36

Question 0

Passive transport

Answer 0

• solute molecule diffuses across a membrane down a concentration gradient
• doesn’t require direct expenditure of energy by cell

Question 1

3 levels of transport in plants

Answer 1

• uptake & release of water & solutes by individual cells
• short-distance cell-to-cell transport at the tissue & organ level
• long-distance transport of sap in xylem & phloem at whole-plant level

Question 2

Transport proteins

Answer 2

may facilitate diffusion by serving as carrier proteins or forming selective channels

Question 3

Carrier proteins

Answer 3

bind selectively to a solute molecule on 1 side of the membrane, undergo conformational change, & release solute molecule on opposite side of membrane

Question 4

Selective channels

Answer 4

passageways by which selective molecules may enter & leave a cell

Question 5

Active transport

Answer 5

• solute molecule is moved across a membrane against the concentration gradient
• requires energy process
• conducted by active transporters