Exam 3: Ch 10 Biomembrane Structure Flashcards Preview

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Flashcards in Exam 3: Ch 10 Biomembrane Structure Deck (40):
1

membrane transport proteins

enable ions, sugars, aa and vitamins to cross the semi permeable phospholipid bilayer

2

receptors

proteins in the cell membrane that allow the cell to recognize chemical signals to adjust metabolism or gene expression

3

cytoskeleton

a network of protein filaments in the cytosol

provide mechanical support for shape and cell movement

4

fluid mosaic model

individual lipids can move horizontally in the membrane and spin in place (but not flip orientation)

membrane fluidity

noncovalent van der waals interactions

5

most common phospholipid in membranes

phosphoglycerides

6

amphipathic membrane structure

fatty acid hydrophobic hydrocarbon tails

polar hydrophilic heads

7

3 types of membrane lipid

phospholipids

sphingolipids

sterols

8

amphipathic things spontaneously form...

micelles

liposomes

membrane bilayers

9

artificial membranes lack _____

proteins

10

lipid raft

less fluid patches of membrane

more cholesterol (stability)

contain plasma membrane proteins involved in transmitting extracellular signals to the inside

11

sphingolipids have different head groups than phospholipids

phosphotidylinositol

signaling molecule

DIAG - diacyl glycerol triphosphate

12

why dont cells fall apart if the membrane is so fluid?

cell walls (plants/bacteria)

ECM

cholesterol

13

type of structure formed by pure phospholipids depends on...

length of tails

degree of saturation

temperature

14

leaflet

half of the phospholipid bilayer

15

phosphatidylcholine

type of phosphoglyceride

most abundant phospholipid in membrane

choline polar head group (OH + phosphate)

16

phospholipases

enzymes that celave ester bonds

produce lysophospholipids (only 1 acyl tail) that are signaling molecules

recognized by receptors and affect physical properties of the memb.

17

plasmalogens

ether linkage - greater chemical stability

human brain and heart

18

structure of sterols

4 rings

cholesterol has an OH on one ring

19

effect of sterols on membranes

structural support

prevent extremely tight packing to allow more fluidity

20

fluorescence recovery after photobleaching (FRAP)

phospholipids with a fluorescent substituent are used to monitor lipid movement

shows lateral movement of proteins and lipids

21

do sphingomyelins form more gel-like and thicker bilayers than phosphoglycerides?

yes

22

bilayers made of cylindrical lipids (long tails and large head groups) are ____, while bilayers made from cone lipids (small head groups) are ______

flat, curved

23

flippase

ATP powered transport proteins

flip exoplasmic lipids (phospholipids) from cytosolic leaflet to exoplasmic leaflet where they function

ex. phosphatidylserine flipped to exoplasmic side where it activates enzymes involved in blood clotting

24

lipid droplet

vesicles made of triglycerides and cholesterol esters that originate from the ER and serve as lipid storage

25

extracellular domain functions

bind extracellular molecules like signaling proteins, ions, and small metabolites

26

intramembrane domain functions

form channels/pores

organize membrane proteins into larger assemblies

27

intramembrane domain functions

anchoring cytoskeletal proteins to the membrane to trigger intracellular signaling pathways

organizing membrane proteins into larger assemblies

28

integral membrane proteins (transmembrane)

span the bilayers and have 3 domains (cytosolic, exoplasmic, transmembrane)

can be attached to ECM

transmembrane domain made of alpha helices and beta sheets

29

lipid-anchored membrane proteins

bound covalently to 1+ lipid molecules

hydrophobic domain embedded in one leaflet and serves as the anchor

30

peripheral membrane proteins

bound to the memb. indirectly by interactions w/ integral or lipid-anchored memb. proteins or directly by interactions w/ head groups

can be attached to ECM too

31

single-pass transmembrane protein

has only 1 membrane spanning alpha helix

ex. Glycophorin A

32

multipass transmembrane protein

an important group has 7 membrane spanning alpha helices

ex. G protein-coupled cell-surface receptors (bacteriorhodopsin)

33

aquaporin

highly conserved proteins that transport water, glycerol, and other hydrophilic molecules

multipass (6 alpha helices) tetramers of 4 identical subunits

ex. glycerol channel Glpf

34

aquaporin 0

most abundant protein in the plasma membrane of fiber cells in the lens of the eye

annular phospholipids - form a tight ring

35

multiple beta strands in _____ form membrane spanning barrels

porins

hydrophilic interior and hydrophobic exterior

36

2 examples of lipid-anchored membrane proteins

Ras (GTPase superfamily)

Rab (GTPase superfamily)

37

orientation of transmembrane glycoproteins/glycolipids

carbohydrate chains in exoplasmic domain

makes them available to interact with ECM, lectins, growth factors, and Ab

38

proteins can be removed from membranes by ______ or high-____ solutions

detergents, high-salt solutions

39

detergent

amphipathic molecules that disrupt membranes by intercalating into them

ex. bile salts, SDS

40

critical micelle concentration (CMC)

concentration of detergent at which micelles form