Chapter 10

Question 1

Lipids

Answer 1

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

Question 2

What are some functions of lipids?

Answer 2

• Energy storage
• Insulation, cushioning
• Cell compartmentalization
• Hormones and signaling

Question 3

______________ are Hydrocarbon Derivatives

Answer 3

Fatty Acids

Question 4

What is the nomenclature for unbranched fatty acid

Answer 4

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)

Question 5

What is the equation like nomenclature for fatty acids

Answer 5

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).

Question 6

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

Answer 6

carboxylic acids

Question 7

Fatty acids usually have ______ - 20 carbons with even number

Answer 7

12

Question 8

____________ 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

Answer 8

IUPAC

Question 9

Double bonds in the fatty acids are _____ conformation

Answer 9

Cis

Question 10

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

Answer 10

C9, C12, & C15

Question 11

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

Answer 11

lower

Question 12

_____________ fatty acids pack with favorable interactions

Answer 12

Saturated

Question 13

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

Answer 13

Unsaturated

Question 14

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

Answer 14

lower

Question 15

Rancidity

Answer 15

Double bond cleavage occurs with oxygen exposure

Question 16

____________ are Fatty Acid Esters of Glycerol

Answer 16

Triacylglycerols

Question 17

The simplest lipids constructed from fatty acids are the ________________

Answer 17

triacylglycerols

Question 18

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

Answer 18

Triacylglycerols

Question 19

Triacylglycerols Provide Stored Energy and ___________________

Answer 19

Insulation

Question 20

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

Answer 20

amphipathic

Question 21

Membrane lipids form __________

Answer 21

Membrane bilayers

Question 22

Glycerophospholipids

Answer 22

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

Question 23

Galactolipids and sulfolipids

Answer 23

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

Question 24

Archaeal tetraether lipids

Answer 24

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

Question 25

Sphingolipids

Answer 25

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

Question 26

Sphingosine and sterols

Answer 26

Compounds characterized by a rigid system of four fused hydrocarbon rings

Question 27

Phospholipids

Answer 27

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

Question 28

Glycolipids

Answer 28

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

Question 29

______________________ are Derivatives of Phosphatidic Acid

Answer 29

Glycerophospholipids

Question 30

Glycerophospholipids (phosphoglycerides)

Answer 30

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

Question 31

Some Glycerophospholipids Have _________-Linked Fatty Acids

Answer 31

Ether

Question 32

Ether lipids

Answer 32

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

Question 33

Plasmaogens

Answer 33

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

Question 34

Plasmalogen

Answer 34

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

Question 35

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

Answer 35

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

Question 36

Sphingolipids

Answer 36

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

Question 37

_____________ are Derivatives of Sphingosine

Answer 37

Sphingolipids

Question 38

Ceramide

Answer 38

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

Question 39

Sphingosine

Answer 39

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

Question 40

Fluid mosaic model

Answer 40

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.

Question 41

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

Answer 41

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)

Question 42

Asymmetric fatty acid synthesis in ______ or bacterial plasma membrane results

Answer 42

E.R

Question 43

Membrane Protein _____________ also varies with cell type & tissue

Answer 43

Composition

Question 44

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

Answer 44

hydrophobic

Question 45

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

Answer 45

(gel) state

Question 46

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

Answer 46

saturation (based on fatty acid properties)

Question 47

_______ cholesterol broadens transition temperatures

Answer 47

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

Question 48

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

Answer 48

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

Question 49

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

Answer 49

Amphipathic

Question 50

Micelles

Answer 50

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.)

Question 51

Bilayer

Answer 51

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

Question 52

Vesicle (liposome)

Answer 52

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

Question 53

What are the 3 forms lipid aggregate makes in water?

Answer 53

1. Micelles 2.Bilayer 3. Vesicle (liposome)

Question 54

Integral membrane proteins

Answer 54

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

Question 55

Peripheral membrane proteins

Answer 55

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)

Question 56

Amphitropic proteins

Answer 56

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

Question 57

Hydropathy Index

Answer 57

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

Question 58

Integral protein helical transmembrane sequences are identified by hydropathy plots

Answer 58

hydropathy plots (20amino acids)

Question 59

The positive inside rule

Answer 59

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

Question 60

Covalently Attached Lipids Anchor Some __________________

Answer 60

Membrane Proteins