Unit 2 - Transport - Feb 24

Question 1

Diffusion

Answer 1

when small mostly-nonpolar molecules and very small polar molecules (e.g., water) can pass directly through the membrane (high->low concentration)

Question 2

Osmosis

Answer 2

movement of water across a semipermeable membrane (toward higher solute concentration - can defy gravity)

Question 3

Hypertonic, Isotonic, Hypotonic solution

Answer 3

Hypertonic: high in solute
Isotonic: equal in solute and water
Hypotonic: low in solute
-Very Hypotonic: blood cell would burst

Question 4

Integral Membrane Proteins

Answer 4

amphipathic proteins that can integrate into the lipid bilayer

Question 5

Transmembrane domains

Answer 5

usually contain hydrophobic amino acid residues

Question 6

Peripheral Membrane Proteins

Answer 6

proteins reversibly associated with either internal/external side of membrane

Question 7

Ion Channels

Answer 7

can open to allow a specific solute to diffuse (esp. ions). They are either open or closed and open-closed status is often regulated

Question 8

Transporters

Answer 8

undergo a conformational (shape) change, binding solutes on one side of the membrane and releasing them on the other

Question 9

Passive Transport

Answer 9

when a solute moves down its concentration gradient spontaneously by diffusion (no energy)

Question 10

Active Transport/Pumping

Answer 10

using energy in some form (esp. ATP) to move solute against concentration gradient

Question 11

Facilitated Diffusion

Answer 11

Diffusion using a transporter or channel

Question 12

Simple Diffusion

Answer 12

just diffusion without anything necessary

Question 13

Sodium-Potassium Pump

Answer 13

uses energy of ATP hydrolysis to create essential electrochemical gradient in animals cells, pumping Na+ ions out and K+ ions in.

Question 14

Due to the sodium potassium pump, Na+ is _ _ the cell and K+ Is _ _ the cell

Answer 14

higher outside, higher inside

Question 15

Coupled Transport

Answer 15

One molecule moves down concentration gradient, releasing energy in a way that drives another molecule to move against concentration gradient (coupled movement)

Question 16

Transporter and Channels are SELECTIVE

Answer 16

selective: binds/recognizes or allows passage of some things but not others (ex. size limit - amino acids and nucleotides but not nucleic acids and proteins)