Chapter 10 Flashcards

1
Q

Lipids

A

heterogenous macromolecules
grouped by solubility in nonpolar solvents -
(no “formula”) (contain C & H & a little O)

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2
Q

What are some functions of lipids?

A
  • Energy storage
  • Insulation, cushioning
  • Cell compartmentalization
  • Hormones and signaling
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3
Q

______________ are Hydrocarbon Derivatives

A

Fatty Acids

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4
Q

What is the nomenclature for unbranched fatty acid

A

Specifies the chain length and number of double bonds, separated by a colon.
(For example, the 16-carbon saturated palmitic acid is abbreviated 16:0)

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5
Q

What is the equation like nomenclature for fatty acids

A

The positions of any double bonds, designated Δ (delta), are specified relative to C-1 by a superscript number indicating the lower-numbered carbon in the double bond. By this convention, oleic acid, with a double bond between C-9 and C-10, is designated 18:1(Δ9) (ex a 20-carbon fatty acid with one double bond between C-9 and C-10 and another between C-12 and C-13 is designated 20:2(Δ9,12).

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6
Q

Fatty acid are long, unbranched _____________ (some branching in bacteria)

A

carboxylic acids

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7
Q

Fatty acids usually have ______ - 20 carbons with even number

A

12

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8
Q

____________ numbering from C-1 at C=O group; Common names based on C=O with adjacent carbons designated alpha, beta, yamma ; terminal –CH3 is w

A

IUPAC

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9
Q

Double bonds in the fatty acids are _____ conformation

A

Cis

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10
Q

The double bonds in fatty acids are usually found at C_, C_, & C_

A

C9, C12, & C15

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11
Q

The longer the fatty acyl chain and the fewer the double bonds, the _________ the solubility in water.

A

lower

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12
Q

_____________ fatty acids pack with favorable interactions

A

Saturated

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13
Q

___________cis fatty acid show less ordered packing due to double bond kink

A

Unsaturated

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14
Q

Less thermal energy disrupts unsaturated fatty acid packing – more unsaturation which results in a _________ melting point

A

lower

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15
Q

Rancidity

A

Double bond cleavage occurs with oxygen exposure

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16
Q

____________ are Fatty Acid Esters of Glycerol

A

Triacylglycerols

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17
Q

The simplest lipids constructed from fatty acids are the ________________

A

triacylglycerols

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18
Q

___________________ are composed of three fatty acids, each in ester linkage with a single glycerol

A

Triacylglycerols

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19
Q

Triacylglycerols Provide Stored Energy and ___________________

A

Insulation

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20
Q

Membrane lipids are _________________: one end of the molecule is hydrophobic, the other hydrophilic

A

amphipathic

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21
Q

Membrane lipids form __________

A

Membrane bilayers

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22
Q

Glycerophospholipids

A

The hydrophobic regions are composed of two fatty acids joined to glycerol

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23
Q

Galactolipids and sulfolipids

A

Contain two fatty acids esterified to glycerol, but lack the characteristic phosphate of phospholipids

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24
Q

Archaeal tetraether lipids

A

Two very long alkyl chains are ether-linked to glycerol at both ends

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25
Q

Sphingolipids

A

In which a single fatty acid is joined to a fatty amine

26
Q

Sphingosine and sterols

A

Compounds characterized by a rigid system of four fused hydrocarbon rings

27
Q

Phospholipids

A

A polar head group is joined to the hydrophobic moiety by a phosphodiester linkage (ex. glycerophospholipids and some
sphingolipids)

28
Q

Glycolipids

A

Sphingolipids lack phosphate but have a simple sugar or complex oligosaccharide at their polar ends

29
Q

______________________ are Derivatives of Phosphatidic Acid

A

Glycerophospholipids

30
Q

Glycerophospholipids (phosphoglycerides)

A

Are membrane lipids in which two fatty acids are attached in ester linkage to the first and second carbons of glycerol, and a highly polar or charged group is attached through a phosphodiester linkage to the third carbon

31
Q

Some Glycerophospholipids Have _________-Linked Fatty Acids

A

Ether

32
Q

Ether lipids

A

One of the two acyl chains is attached to glycerol in ether, rather than ester, linkage

33
Q

Plasmaogens

A

The ether-linked chains may contain a double bond between C-1 & C-2

34
Q

Plasmalogen

A

Have both ester and vinyl-ether links between
glycerol and fatty acids; choline or ethanolamine heads

35
Q

____________ are enriched in vertebrate heart, muscle & peripheral nerves & may protect against oxidative damage (free radicals) and serve as molecule precursors

A

Plasmalogen (ex. Platelet-activating factor signals for platelet aggregation)

36
Q

Sphingolipids

A

Have a polar head group and two nonpolar tails, but unlike glycerophospholipids and galactolipids they contain no glycerol

37
Q

_____________ are Derivatives of Sphingosine

A

Sphingolipids

38
Q

Ceramide

A

When a fatty acid is attached in amide linkage to the —NH2 on C-2, the resulting compound

39
Q

Sphingosine

A

C18 amino alcohol: C1-OH; C2-NH2, C3-OH & amide link to fatty acid (Abundant in mammalian
CNS lipid membranes)

40
Q

Fluid mosaic model

A

Phospholipids form a bilayer in which the nonpolar regions of the lipid molecules in each layer face the core of the bilayer and their polar head groups face outward, interacting with the aqueous phase on either side.

41
Q

Membrane _____________ require variable lipid and protein composition across organelles, tissue, and organism

A

functions, (* Selective cell boundaries and compartments for nutrients, waste, and metabolites
* Sensing and producing signals and information
* Storing energy as a proton and ion gradients that supports ATP synthesis)

42
Q

Asymmetric fatty acid synthesis in ______ or bacterial plasma membrane results

A

E.R

43
Q

Membrane Protein _____________ also varies with cell type & tissue

A

Composition

44
Q

In the fluid mosaic model, proteins are embedded in this bilayer sheet, their ___________ domains in contact with the fatty acyl chains of membrane lipids

A

hydrophobic

45
Q

In fluid mosaic model, membrane thicker in solid ___________ with extended and packed lipid tail

A

(gel) state

46
Q

Organisms alter fatty acid __________ and length to maintain fluid, dynamic structure from 10-40oC

A

saturation (based on fatty acid properties)

47
Q

_______ cholesterol broadens transition temperatures

A

Steroid (* Limit movement of fatty acid tails
* Reduce van der Waals interactions)

48
Q

Lipids move _________ within a bilayers in 2D fluid (like machine oil)

A

rapidly (lateral diffusion) & transverse diffusion its very slow (flip flop)

49
Q

____________ lipids spontaneously aggregate in aqueous solutions, Hydrophilic heads interact with water; nonpolar tails bury inside

A

Amphipathic

50
Q

Micelles

A

Form with wider head-groups than hydrophobic tails (make a sphere shape with the hydrophobic head outers & hydrophilic tail inwards) (ex. fatty acids and detergents (~10-1000 lipids above a threshold conc.)

51
Q

Bilayer

A

Two lipid monolayers (leaflets) form a two-dimensional sheet where the hydrophobic tails on the inside & the hydrophilic head on the outside

52
Q

Vesicle (liposome)

A

Are sealed lipid bilayers with internal aqueous cavities that can fuse with other vesicles; flexible and self-sealing

53
Q

What are the 3 forms lipid aggregate makes in water?

A
  1. Micelles
    2.Bilayer
  2. Vesicle (liposome)
54
Q

Integral membrane proteins

A

Are embedded within the lipid bilayer and are
removable only by agents that overcome the hydrophobic effect, such as detergents, organic solvents, or denaturants

55
Q

Peripheral membrane proteins

A

Associate with the membrane through
electrostatic interactions and hydrogen bonding with hydrophilic domains of integral proteins and with membrane lipids ( globular associated with membrane surfaces via non-covalent
interactions; high ionic strength and ΔpH disrupts)

56
Q

Amphitropic proteins

A

Associate reversibly with membranes and are therefore found both in the membrane and
in the cytosol

57
Q

Hydropathy Index

A

Globular regions emerge with glycosylated (exterior) or charged (interior)
* Delta G transfer from organic to water solution calculated per 20 amino acid window

58
Q

Integral protein helical transmembrane sequences are identified by hydropathy plots

A

hydropathy plots (20amino acids)

59
Q

The positive inside rule

A

The positively charged Lys and Arg residues of
membrane proteins occur more commonly on the cytoplasmic face of
membranes

60
Q

Covalently Attached Lipids Anchor Some __________________

A

Membrane Proteins