Chap 4 Pt 2

Question 1

Membrane Transport

Answer 1

; Process of obtaining (stuff enters) and eliminating substances (stuff exits) across the plasma membrane

Question 2

Passive Process

Answer 2

Does not require energy
Depend on substances moving down concentration gradient
Two types: diffusion and osmosis

Question 3

Active Processes

Answer 3

Require energy
Two types: active transport and vesicular transport

Question 4

Diffusion

Answer 4

Net movement of a substance from area of greater concentration to area of lesser concentration

Question 5

Diffusion, why?

Answer 5

Why? Molecules and ions in constant motion
–kinetic energy

Question 6

Passive Processes: Rate of Diffusion Influenced By

Answer 6

“Steepness” of concentration gradient
Measure of the difference in concentration between two areas
Steeper gradient (biggest difference) faster diffusion

Question 7

Temperature

Answer 7

Reflects kinetic energy or random movement
More movement with higher temperature faster diffusion

Question 8

Passive Process: Simple Diffusion 1

Answer 8

Molecules pass between phospholipids
Small and nonpolar solutes

Question 9

Simple Diffusion 2

Answer 9

O2 and CO2, fatty acids, ethanol, urea
Not regulated by plasma membrane!!!!

Question 10

Simple Diffusion 3

Answer 10

Movement dependent on concentration gradient
Continues to move as long as gradient exists

Question 11

Facilitated Diffusion

Answer 11

Transport process for small charged or polar solutes
**Requires assistance from plasma membrane proteins

Question 12

Facilitated Diffusion

Answer 12

Two types
Channel-mediated diffusion
Carrier-mediated diffusion

Question 13

Channel-mediated diffusion 1

Answer 13

Movement of small ions through protein channels

Question 14

Channel mediated diffusion 2

Answer 14

**Channels specific for each ion

Question 15

Leak channels

Answer 15

Continuously open

Question 16

Gate Channel

Answer 16

Usually closed
Opens in response to stimulus for fraction of second

Question 17

Carrier - mediated diffusion 1

Answer 17

Small polar molecules assisted across membrane by carrier protein

Question 18

Carrier - mediated diffusion 2

Answer 18

Binding of substance causing change in carrier protein shape

Question 19

Carrier - mediated diffusion 3

Answer 19

Releases substances on other side of membrane

Question 20

Osmosis

Answer 20

Movement of water (solvent), not solutes

Question 21

Osmosis 2

Answer 21

Passive movement of water through selectively permeable membrane

Question 22

Osmosis 3

Answer 22

Membrane allows passage of water
Membrane prevents passage of most solutes
Water moves from greater concentration of water to lower concentration of water
Water moves from lower concentration of solutes to higher concentration of solutes

Question 23

2 types of soluble (1) permeable

Answer 23

solutes
Pass through bilayer
small and nonpolar solutes (oxygen, carbon dioxide, urea

Question 24

2 types of soluble (2) Nonpermeable

Answer 24

solutes
Don’t pass through bilayer
charged, polar, or large solutes (ions, glucose, proteins)

Question 25

2 ways water crosses membrane (1)

Answer 25

A small portion slips between molecules of phospholipid bilayer

Question 26

2 ways water crosses membrane (2)

Answer 26

Moves through special protein water channels—aquaporins