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Flashcards in Chapter 9 Deck (19)
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0
Q

Bacteriorhodopsin

A

Homotrimeric protein with 247 residues
Synthesized by halophillic archaea bacterium
Functions as proton pump, light driven
Retinal (vitamin A) = light absorption group

1
Q

Transmembrane proteins

A

Alpha belies or beta sheets
Must fold to satisfy h-bonding potential of polypeptide backbone
Difficult to crystallize

2
Q

Porins

A

Act as channels through which molecules can diffuse
Found in outer membrane of gram-negative bacteria mostly
Monomers or trimers
Minimum of 16-stranded antiparallel beta barrels that form central channel

3
Q

3 types of lipid linked proteins

A

Prenylated, fatty acylated, GPI proteins

4
Q

Prenylated Proteins

A

Its lipids are built from isoprene units
Most common prenylation site is the C-terminal tetra peptide C-X-X-Y
Y influences the prenylation; is Ala, Met or Ser OR Leu

5
Q

Fatty acylated proteins

A

Myristic acid and palmitic acid = linked to membrane proteins
Many participate in transmembrane signaling

6
Q

GPI-linked proteins

A

Occur in all eukaryotes, abundant in some parasitic Protozoa
Located on exterior of the protein
It’s core tetra saccharide varies depending on its linked protein

7
Q

The fluid mosaic model

A

Accounts for lateral diffusion, integral proteins diffuse laterally in the lipid matrix, unless restricted by other cell components

8
Q

Spectrin

A

Two similar polypeptide chains, an alpha beta dimer, each contain a triple stranded alpha helical coiled coil.
Form part of erythrocyte membrane exoskeleton

9
Q

Spectrin

A

Accounts of 75% of erythrocyte membrane skeleton

Two similar polypeptide chains, an alpha beta dimer, each contain a triple stranded alpha helical coiled coil.

10
Q

Flippases

A

Membrane protein that facilitates flip flop process by facilitated diffusion

11
Q

Phospholipid transferase

A

Membrane protein that facilitates flip flop process by active transport

12
Q

Lipid rafts

A

Consist of closely packed sphingolipids and cholesterol. Diffuse laterally within the membrane, certain proteins associate with the raft (including some that participate in transmembrane signaling)

13
Q

Erythrocytes

A

Red Blood Cells

14
Q

Translocon

A

Multifunctional trans-membrane pore
The channel-forming component of the translocon is a heterotrimeric protein named Sec61 in mammals and SecY in prokaryotes

15
Q

Liposomes

A

Self-sealing solvent filled vesicles bound by a single bilayer.
Serve as models of biological membranes and also hold promise as vehicles for drug delivery.

16
Q

Transverse diffusion

A

Transverse diffusion (a flip-flop) is defined as the transfer of a phospholipid molecule from one bilayer leaflet to the other by active transport (phospholipid translocases) or passive diffusion (flippases)

17
Q

Clathrin

A

A protein that forms a polyhedral framework around vesicles that transport TM, GPI-linked, and secreted proteins from the Golgi to the plasma membrane.
Built from network of triskelions.

18
Q

Lateral diffusion

A

The pairwise exchange of neighboring phospholipid molecules in the same bi-layer leaflet