Membrane Proteins Flashcards Preview

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Flashcards in Membrane Proteins Deck (25)
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1
Q

diffusion

A

spontaneous movement of a substance from 1 region to another, often w/ net movement from high conc. to low conc.

2
Q

facilitated diffusion

A

passive transport of a substance across a membrane w/ assistance of transmembrane carrier proteins or channel proteins

3
Q

carrier protein

A

specialized membrane proteins that change shape during the transport process

4
Q

channel protein

A

enable ions or polar molecules to move across lipid bilayers efficiently in response to existing gradient

5
Q

active transport

A

movement of ions/molecules across membrane against an electrochemical gradient

  • requires energy & assistance of transport protein
  • must counteract entropy ↓
6
Q

protein models

A

(1) fluid mosaic model

(2) sandwich model

7
Q

freeze-fracture electron microscopy

A

innovative technique for visualizing surface of plasma membranes

8
Q

peripheral membrane protein

A

protein that binds to membrane w/out passing through & a protein does not span entire lipid bilayer & associates w/ only one side of bilayer

  • some only found in interior cell
  • others only found on exterior cell
  • often attached to transmembrane proteins
  • come off easily
9
Q

integral membrane protein

A

protein that spans membrane & has segments facing both interior & exterior surfaces

  • hydrophobic embedded part
  • some transmembrane parts

aka. transmembrane protein

10
Q

detergent

A

small amphipathic molecule used to solubilize hydrophobic molecules in aq. solution

11
Q

electrochemical gradient

A

combo of ion’s [] gradient & electrical (charge) gradient across a membrane that affects ion diffusion across membrane

electrical + chemical -> diffusion

12
Q

channel proteins

A

types of pores in cell membrane

  • enable ions / polar molecules to move across lipid bilayer in response to existing gradient
  • selective: permits particular types of ions or small molecules to pass through only
13
Q

gated channel

A

channel protein that opens/closes in response to specific stimulus

(ie) aquaporin & ion channel
(ie) voltage & ligand gated

14
Q

aquaporin

A

type of channel protein in which water moves cross plasma membrane over 10x faster than w/out aquaporin

“water-pores”

15
Q

ion channel

A

specialized protein channel that allows certain ions to diffuse across plasma membrane down an electrochemical gradient
- form pores in membrane, which is where ions move through

16
Q

passive transport

A

powered by diffusion along electrochemical gradient

  • no need energy
  • use gradients as force

(ie) facilitated diffusion

17
Q

secondary active transport

A

gradient set up by pump provides energy required to pwr movement of diff. molecule against its particular gradient

  • link passive to active
  • glucose movement in small intestine against [] gradient
  • Na+ down gradient, glucose against gradient
  • no ATP

aka. cotransport

18
Q

pump

A

protein membrane that can:

(1) hydrolyze ATP
(2) change shape
(3) pwr active transport of specific ion/small molecule across plasma membrane against electrochemical gradient
- independent of gradients

19
Q

primary active transport

A

critical for membrane potential

20
Q

channel fcn

A

(1) passive transport
(2) facilitated diffusion
(3) electrochemical gradient

21
Q

carrier protein fcn

A

(1) passive transport
(2) facilitated diffusion
(3) electrochemical gradient

22
Q

voltage gated

A

charge (+/-) depends on open/close

23
Q

ligand gated

A

depends on if ligand (binds to receptor) is on channel or not

24
Q

membrane-associated proteins

A

(1) peripheral membrane protein
(2) integral membrane protein
(3) glycoprotein

25
Q

glycoprotein

A

only present on exterior of cell or inside of golgi

  • creates diff. blood types
  • cell receptors