New Material for Final Exam

Question 1

Saturated Fatty Acids

Answer 1

no double bonds in their carbon chain

Question 2

Unsaturated Fatty Acids

Answer 2

contain cis double bonds, which are arranged so that there is no conjugation

Question 3

Tm

Answer 3

increases with additional CH2 groups and counteracted by presence of CIS double bonds

Question 4

Myristic Acid

Answer 4

14:0 CH3(CH2)12COOH, know how to draw structure

Question 5

Palmitic Acid

Answer 5

16:0 CH3(CH2)14COOH, know how to draw structure

Question 6

Stearic Acid

Answer 6

18:0 CH3(CH2)16COOH, know how to draw structure

Question 7

Palmitoleic Acid

Answer 7

16:1 (Delta 9), know how to draw structure

Question 8

Oleic Acid

Answer 8

18:1 (Delta 9), know how to draw structure

Question 9

Linoleic Acid

Answer 9

18:2 (delta 9,12), know how to draw structure

Question 10

Triacylglycerols

Answer 10

Made up of 3 fatty acids linked to glycerol by an ester bond
Stored in adipose tissue to provide: energy storage, insulation, and cushioning

Question 11

Glycerophospholipids

Answer 11

Similar to triacylglycerols but has phosphate instead of one fatty acid
Could be linked to another molecule that contains a hydroxyl that includes CHOLINE or ETHANOLAMINE, SERINE, INOSITOL, or GLYCEROL (linked to another phospholipid)

Question 12

Phospholipids

Answer 12

amphipathic and this form membrane bilayers

Question 13

Sphingolipids

Answer 13

derived from sphingosine, linked to another fatty acid by an amide bond known as ceramide, end hydroxyl group of a ceramide may be linked to a head group

Question 14

Cholesterol

Answer 14

Rigid semi-planarity, weakly amphipathic, precursor of steroid hormones, critical component of membranes

Question 15

Groups of Lipids

Answer 15

amphipathic and this self-associate into micelles and bilayers (membranes). When bilayers form spheres, these are vesicles

Question 16

Individual lipids in a membrane:

Answer 16

rapidly laterally mobile, almost never swap sides, confused by interactions between polar head groups

Question 17

Lipids change sizes due to

Answer 17

flippases, flippases, and scramblases

Question 18

Asymmetric

Answer 18

two sides inner and outer leaflets of a membrane

Question 19

Liquid-ordered

Answer 19

below the transition temperature, membrane forms a sort of rigid gel, disrupts “gel” formation below transition temperature

Question 20

Liquid-disordered

Answer 20

above the transition temperature, membrane is much more fluid

Question 21

Lipid rafts

Answer 21

dense microdomains made up of cholesterol, glycosphingolipids and associated proteins

Question 22

Membrane proteins

Answer 22

remain (partially) solvent accessible, interact with the membrane with specific directionality

Question 23

Peripheral membrane proteins

Answer 23

weak association with polar head groups

Question 24

Amphitropic proteins

Answer 24

spend time both on and off the membrane

Question 25

Integral membrane proteins

Answer 25

traverse the membrane (usually exposed to both sides), hydrophobic residues are exposed to the membrane interior, loops are absent from the protein interior, positive charges are more common on the cytoplasmic side, Tyr, and Trp often sit at the interface between lipid and aqueous phases
Examples: K+ channel, maltoporin, outer membrane phospholipase A, OmpX, and phosphoporin E

Question 26

Fatty Acylation

Answer 26

found on cell interior

Question 27

Prenylation

Answer 27

found on cell interior

Question 28

Glycophosphatidylinositol

Answer 28

found on exterior proteins

Question 29

Equilibrium

Answer 29

concentrations are equal on both sides of the membrane

Question 30

Active transport

Answer 30

requires energetic coupling

Question 31

Passive transport

Answer 31

does not require energetic coupling

Question 32

Moving molecules through a membrane is difficult:

Answer 32

some (nonpolar) molecules pass through a membrae by simple diffusion, but it is essentially impossible for polar molecules to do so

Question 33

Ionophores (carrier molecules)

Answer 33

take ions down a gradient, unfavorable: against gradient not useful, favorable: useful

Question 34

Channels (porins)

Answer 34

down electrochemical gradient; may be gated by a ligand or ion

Question 35

Transporters (permeases)

Answer 35

against electrochemical gradient, driven by ion moving down its gradient, only open to one side of a membrane at a time, usually follow Michaelis-Menten equation (w/ Vmax & Kt, etc.)

Question 36

Aquaporin

Answer 36

allows water in at incredibly fast rate, prevents H+ from entering cell and disrupting electrochemical gradients
Repels H3O+ with positively charged R narrowest part of channel
prevents proton hopping by positioning H-bonding Ns (of NRA sequence) too far apart to allow H-bonding between water molecules

Question 37

Symport

Answer 37

ions go same direction, ions go out of cell, favorable

Question 38

Antiport

Answer 38

ions go opposite direction, switch signs, unfavorable

Question 39

Active Transport

Answer 39

moves particles up a gradient by using the free energy released by another process

Question 40

Primary active transport

Answer 40

transporter itself generates this energy, usually by ATP hydrolysis

Question 41

Secondary active transport

Answer 41

another transporter generates the energy by creating another gradient

Question 42

SERCA Pumps

Answer 42

uses ATP hydrolysis to push 2 Ca2+ out of the cell
5 domains: 2 transmembrane domains (T,S) and 3 cytosilic domains (N,P,A)