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MCP Unit 1 > Lecture 7: Overview Of Membrane Structure > Flashcards

Lecture 7: Overview Of Membrane Structure Flashcards

0
Q

Are membranes held together by covalent interactions?

A

No

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1
Q

Which functional groups allow a cell to be identified by its membrane makeup?

A

Proteins, lipids, carbs

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2
Q

Are biological membranes (a)symmetric?

A

Asymmetric

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3
Q

Under physiological conditions, are membranes fluid or rigid?

A

Fluid

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4
Q

Which forms do amphipathic lipids assume in an aqueous environment?

A

Micelles

Lipid bilayers

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5
Q

Phospholipids, the lipid components of biological membranes, are comprised of which 4 components?

A

Fatty acid(s)
Backbone (sometimes glycerol)
Phosphate
Alcohol head group

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6
Q

What is the phospholipid backbone in phosphoglycerides?

A

Glycerol

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7
Q

What is the phospholipid backbone in sphingomyelin?

A

Sphingosine

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8
Q

What two elements comprise phospholipid head groups?

A

Phosphate and alcohol

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9
Q

Which four alcohols commonly form phospholipid head groups?

A

Serine
Ethanolamine
Choline
Inositol

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10
Q

List two other membrane lipids

A

Glycolipids

Cholesterol

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11
Q

What is the hydrophobic part of phosphoglycerides?

A

Fatty acid chains

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12
Q

What is the hydrophilic part of phosphoglycerides?

A

Phosphorylated alcohol

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13
Q

What is the hydrophobic part of sphingomyelin?

A

Fatty acid chains

Hydrocarbon chain of sphingosine

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14
Q

What is the hydrophilic part of sphingomyelin?

A

Phosphoryl choline

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15
Q

What is the hydrophobic part of glycolipid?

A

Fatty acid chain

Hydrocarbon chain of sphingosine

16
Q

What is the hydrophilic part of glycolipid?

A

1+ sugars

17
Q

What is the hydrophobic part of cholesterol?

A

Everything except -OH

18
Q

What is the hydrophilic part of cholesterol?

A

-OH group

19
Q

Which four forces drive spontaneous formation of lipid bilayers in aqueous solution?

A

Hydrophobic effect - primary
Van der waals forces - close packing of tails
Electrostatic + H-bond - between polar head groups and water molecules

20
Q

Is transverse diffusion of membrane lipids fast or slow?

A

Slow

Protein mediated

21
Q

Is lateral diffusion of membrane lipids fast or slow?

A

Fast

22
Q

Do longer hydrocarbon chains make a membrane more fluid or more rigid?

A

More rigid

More van der waals interactions

23
Q

Does unsaturation of hydrocarbon chains make a membrane more fluid or more rigid?

A

More fluid

Can’t pack as tightly

24
Q

Does cholesterol increase or decrease membrane fluidity?

A

Decreases fluidity
Makes membrane more rigid
Blocks large motions

25
Q

How does cholesterol help membranes stay fluid over the range of physiological temperatures, even though it decreases membrane fluidity?

A

Doesn’t allow as much movement… But also keeps lipids from packing too tightly so membranes can’t solidify into gel phase

26
Q

Which two factors determine how well a molecule will be able to pass through a membrane without assistance?

A

Polarity and size

27
Q

How does liposome delivery of a drug work?

A

Drug is packaged into liposomes, targeted with membrane tag

28
Q

How are peripheral membrane proteins attached?

A

Bound to surface of membrane or to other integral membrane proteins

29
Q

How are integral membrane proteins attached?

A

Penetrate lipid bilayer

30
Q

In what structure do integral membrane proteins usually cross the membrane?

A

Alpha helices

31
Q

What feature predicts whether a protein will be an integral membrane protein and how many times it will pass the membrane?

A

Polarity of distinct regions

32
Q

In the fluid mosaic model of membranes, what type of diffusion of membrane proteins is possible?

A

Lateral only. No transverse

33
Q

In the fluid mosaic model, what is the solvent for membrane proteins?

A

Lipid bilayer is solvent

34
Q

Why don’t lipid rafts fit into the fluid mosaic model well?

A

Less fluid, more resistant to detergent solubilization

35
Q

In what four processes do lipid rafts participate?

A

Signal transduction
Protein sorting
Recognition
Viral entry or exit from cell

MCP Unit 1 (7 decks)

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