p.28
Lipid Rafts and Cellular Signaling
What are lipid rafts enriched with?
Cholesterol and sphingolipids.
p.27
Membrane Dynamics and Fluidity
What effect does slower protein diffusion in membranes have on cells?
It allows cells to restrict the localization of cellular signaling.
p.5
Fatty Acid Classification and Properties
What does the term 'omega' refer to in fatty acids?
The distance of the double bond from the 'ω' carbon.
p.17
Membrane Structure and Function
What is the distribution of phosphatidylserine in the membrane?
It is more located in the inner monolayer and is negatively charged.
p.14
Sphingolipid Structures
What is a ceramide and its role?
A ceramide is sphingosine with a fatty acid residue at C2, playing an important role in apoptosis and signaling.
p.8
Fatty Acid Classification and Properties
What does the systematic name of a fatty acid indicate?
The chain length and the location of any double bonds.
p.17
Membrane Structure and Function
What is the significance of the charge difference in the lipid bilayer?
There is a significant difference in charge between the two halves of the bilayer.
p.14
Sphingolipid Structures
What defines a cerebroside?
Cerebrosides are sphingolipids with one single sugar linked by a glycosidic bond at C1 of the sphingosine backbone, mostly found in neurons.
p.26
Membrane Proteins and Their Interactions
What is the relationship between lipid length and residency time on membranes?
Longer lipid chains lead to stronger interactions and longer residency times.
p.21
Role of Cholesterol in Membranes
What is the effect of cholesterol on the mobility of the lipid bilayer at high temperatures?
It restricts the mobility of the lipid bilayer.
p.7
Fatty Acid Classification and Properties
How does the trans configuration affect the melting temperature (Tm) of fatty acids?
Trans configuration results in a higher Tm.
p.12
Membrane Structure and Function
What does a lipid bilayer consist of?
Two layers of lipids arranged with hydrophilic heads facing outward and hydrophobic tails facing inward.
p.3
Phospholipid and Sphingolipid Structures
What contributes to the variety of phospholipids?
Types of fatty acids and types of the phosphate head.
p.23
Membrane Proteins and Their Interactions
What types of modifications are commonly found on membrane proteins?
Various lipid modifications.
p.29
Phospholipid and Sphingolipid Structures
What do kinases catalyze in the phosphatidylinositol signaling pathway?
The transfer of Pi from ATP to OH groups at positions 5 and 4 of the inositol ring.
p.8
Fatty Acid Classification and Properties
What is the configuration of the double bond in Oleate?
cis - configured double bond between C9 and C10.
p.25
Membrane Proteins and Their Interactions
What role does negatively charged PS play in the inner leaflet of membranes?
It cooperates with membrane-targeting motifs in proteins to increase their affinity to membranes.
p.24
Membrane Proteins and Their Interactions
What is the role of lipid modification (prenylation) in GTPase RALA?
It interacts with negatively charged phospholipids in the inner membrane.
p.10
Membrane Dynamics and Fluidity
What is the significance of the head group in phospholipids?
It influences the interaction with proteins and contributes to membrane dynamics.
p.16
Membrane Dynamics and Fluidity
Which lipids form regions of neutral or positive curvature?
PC (phosphatidylcholine) and SM (sphingomyelin).
p.12
Membrane Structure and Function
What is a liposome?
A structure formed by a lipid bilayer.
p.23
Membrane Proteins and Their Interactions
What facilitates the localization of membrane-attached proteins?
Lipid modification on proteins and charged phospholipids.
p.26
Membrane Proteins and Their Interactions
How does the strength of protein-lipid binding motifs affect residency time on membranes?
Stronger binding motifs lead to longer residency times on membranes.
p.29
Phospholipid and Sphingolipid Structures
What is the product of the phosphorylation of phosphatidylinositol?
Phosphatidylinositol-4,5-bisphosphate (PIP2).
p.2
Biosynthesis of Lipids
What do chylomicrons transform into during metabolism?
Free fatty acids (FFA) and other forms of lipoprotein particles.
p.25
Membrane Proteins and Their Interactions
What is the sequence found in the N-terminus of the Src protein?
Myristate - GSS K S K P K DPSQ RRR.
p.2
Membrane Structure and Function
What characteristic makes membrane lipids ideal for forming a stable bilayer?
They are amphiphilic (amphipathic).
p.15
Lipid Rafts and Cellular Signaling
What are sphingolipid metabolites known for?
They can function as signaling molecules.
p.12
Membrane Structure and Function
What can be observed in an electron micrograph of a liposome?
The structure of the lipid bilayer.
p.11
Membrane Structure and Function
What are micelles formed by soaps/detergents?
Aggregates of sodium or potassium salts of fatty acids.
p.14
Sphingolipid Structures
Where are sphingomyelins primarily found?
In animal cell membranes, especially in the membranous myelin sheath surrounding some nerve cell axons.
p.34
Eicosanoids and Their Biological Functions
What are eicosanoids?
Group of highly active compounds derived from long chain polyunsaturated fatty acids like arachidonic acid.
p.29
Phospholipid and Sphingolipid Structures
What role does phosphatidylinositol play in cellular processes?
It is involved in phospholipid metabolism and signaling.
p.21
Role of Cholesterol in Membranes
What happens to the lipid phase when cholesterol is inserted above the melting temperature (Tm)?
It converts the phase of lipid from liquid disordered to liquid ordered.
p.2
Types of Lipids in Membranes
What types of lipids are included in membrane lipids?
Phospholipids, sphingolipids, and cholesterol.
p.32
Phospholipid and Sphingolipid Structures
What is the function of phospholipase?
To hydrolyze phospholipids into fatty acids and other lipophilic substances.
p.32
Phospholipid and Sphingolipid Structures
What distinguishes the four major classes of phospholipases?
The type of reaction they catalyze.
p.13
Sphingolipid Structures
What is the backbone structure of sphingolipids?
A 3-carbon backbone, but with sphingosine instead of glycerol.
p.35
Membrane Structure and Function
What model describes the dynamic nature of native membranes?
Singer and Nicholson’s 'Fluid Mosaic Model'.
p.16
Membrane Dynamics and Fluidity
What is the effect of saturated fatty acids on lipid packing?
They influence the curvature and packing of lipids.
p.18
Membrane Dynamics and Fluidity
What effect does heat have on lipid bilayers?
It promotes transition from a gel state to a fluid-like state.
p.35
Eicosanoids and Their Biological Functions
What function can Eicosanoids serve?
As agonists for receptors.
p.20
Role of Cholesterol in Membranes
What effect can a rapid transition of cholesterol have on cells?
It may be unfavorable to cell functions and permeability.
p.31
Membrane Proteins and Their Interactions
What is the role of Ca++ in phosphatidylinositol signal cascades?
Ca++ signaling is involved in the activation of protein kinase C (PKC).
p.8
Fatty Acid Classification and Properties
What is the systematic name of Oleate?
cis - ∆ 9 - Octadec enoate.
p.31
Membrane Proteins and Their Interactions
What is activated by Ca++ signaling in phosphatidylinositol cascades?
Protein kinase C (PKC) is activated.
p.17
Membrane Structure and Function
Which lipids are found in the inner monolayer of the membrane?
Phosphatidylserine (PS) and phosphatidylethanolamine (PE) with unsaturated fatty acids.
p.1
Membrane Structure and Function
What are the important functions of membranes?
They serve as surface barriers and carriers.
p.23
Membrane Proteins and Their Interactions
What is the role of lipid modifications on membrane proteins?
To facilitate their localization to the membrane.
p.30
Phospholipid and Sphingolipid Structures
What is the role of PI3K in signaling?
PI3K phosphorylates PIP2 at the '3' position to generate PIP3.
p.10
Phospholipid and Sphingolipid Structures
Name a phospholipid that is anionic.
Phosphatidylinositol (PIP3).
p.10
Membrane Proteins and Their Interactions
Which basic residues in proteins interact with acidic phospholipids?
Lysine (K) and Arginine (R).
p.34
Eicosanoids and Their Biological Functions
Which common medications affect eicosanoid metabolism?
Aspirin, Ibuprofen, and Corticosteroids.
p.22
Membrane Proteins and Their Interactions
What characterizes a multi-transmembrane protein?
It spans the membrane multiple times.
p.28
Membrane Proteins and Their Interactions
What types of membrane proteins can be found?
Integral and peripheral proteins.
p.22
Membrane Proteins and Their Interactions
What are membrane-attached proteins?
Proteins that interact via lipid-lipid or protein-protein interactions.
p.31
Membrane Proteins and Their Interactions
How is Ca++ released in phosphatidylinositol signal cascades?
Ca++ is released from the endoplasmic reticulum (ER).
p.5
Fatty Acid Classification and Properties
What roles do Omega-3 and Omega-6 fatty acids play in the body?
They are important for development, brain function, etc.
p.23
Membrane Proteins and Their Interactions
What do membrane-targeting domains in proteins bind to?
Negatively charged phospholipid motifs on the membrane.
p.21
Role of Cholesterol in Membranes
What role does cholesterol play in membrane fluidity at high temperatures?
It reduces the membrane's permeability to small molecules and makes the membrane less fluid.
p.1
Membrane Structure and Function
What is the plasma membrane?
A type of membrane that surrounds the cell.
p.35
Membrane Structure and Function
What determines the physical properties of lipid membranes?
Differences in lipid groups.
p.25
Membrane Dynamics and Fluidity
How does the presence of 33% PS in PC membranes affect the partition coefficient?
It increases the partition coefficient to K = 10^7 M^-1, which is 1000-fold higher.
p.35
Membrane Structure and Function
What is responsible for the assembly of lipids into bilayer membranes?
The hydrophobic nature of lipids.
p.16
Membrane Dynamics and Fluidity
Which lipids are more likely to give rise to negative curvature?
PE (phosphatidylethanolamine) and PS (phosphatidylserine).
p.27
Membrane Dynamics and Fluidity
How does the diffusion of proteins in membranes compare to that in the cytoplasm?
Diffusion of proteins on membranes is slower than in the cytoplasm.
p.3
Phospholipid and Sphingolipid Structures
What are the two components attached to the glycerol backbone in glycerophospholipids?
Two fatty acid tails (Acyl groups) and a phosphate-linked head.
p.30
Phospholipid and Sphingolipid Structures
What does PI3K stand for?
Phosphoinositide 3-kinase.
p.10
Phospholipid and Sphingolipid Structures
What is the role of the head group in phospholipids?
It gives rise to various net charges.
p.21
Role of Cholesterol in Membranes
How does cholesterol affect membrane interactions at low temperatures?
It prevents the membrane from freezing by interfering with interactions between fatty acid chains.
p.34
Eicosanoids and Their Biological Functions
What role do eicosanoids play in the body?
They act locally as bioactive signaling molecules to activate receptors involved in various physiological processes.
p.24
Membrane Proteins and Their Interactions
How does EGFR interact with the plasma membrane?
It contains a stretch of basic residues that closely interacts with acidic phospholipids of the inner leaflet.
p.25
Membrane Proteins and Their Interactions
What conclusion can be drawn about membrane targeting motifs?
They can cooperate to increase binding to membranes.
p.18
Membrane Dynamics and Fluidity
What types of interactions contribute to the stability of lipid bilayers?
Van der Waals interactions and hydrogen bonds with the aqueous environment.
p.18
Membrane Dynamics and Fluidity
Where are lipid tails most mobile in the bilayer?
At the center of the bilayer.
p.32
Phospholipid and Sphingolipid Structures
What does Phospholipase C release?
Diacylglycerol and a phosphate-containing head group.
p.22
Membrane Proteins and Their Interactions
How are some membrane proteins anchored to the cytosolic surface?
By an amphiphilic α helix through the hydrophobic face of the helix.
p.4
Fatty Acid Classification and Properties
From which end is the carbon of a fatty acid numbered?
From the carboxylate end.
p.24
Membrane Proteins and Their Interactions
What types of basic residues are often found in proteins that interact with acidic phospholipids?
Lysine (K) and Arginine (R).
p.19
Membrane Dynamics and Fluidity
What is the relationship between membrane transition temperature (Tm) and fatty acid components?
Tm is influenced by the length and saturation of fatty acids in membrane lipids.
p.11
Membrane Structure and Function
How do lipids with two acyl chains behave in water?
They pack into bilayers to avoid water near the hydrophobic tail group.
p.8
Fatty Acid Classification and Properties
What is the structure of Oleate?
An 18:1, unsaturated fatty acid.
p.11
Membrane Structure and Function
What is the role of the hydrophobic tail group in lipid bilayers?
To avoid contact with water.
p.16
Membrane Dynamics and Fluidity
How does the shape of lipids affect membranes?
It impacts membrane dynamics.
p.19
Membrane Dynamics and Fluidity
Which type of unsaturated fatty acid contributes the most to lowering Tm?
A mid-chain double bond unsaturated fatty acid.
p.34
Eicosanoids and Their Biological Functions
What are the most important types of eicosanoids?
Prostaglandins, thromboxanes, and leukotrienes.
p.34
Eicosanoids and Their Biological Functions
How long is the half-life of eicosanoids?
They have very short half-lives.
p.13
Sphingolipid Structures
How are the tails of sphingolipids structured?
One tail is part of sphingosine and the other is a fatty acid linked by an amide bond.
p.28
Membrane Structure and Function
What is the Fluid Mosaic Model also known as?
The Singer-Nicolson model.
p.22
Membrane Proteins and Their Interactions
What is a GPI anchor?
An oligosaccharide linker to phosphatidylinositol in the non-cytosolic monolayer.
p.22
Membrane Proteins and Their Interactions
What distinguishes integral membrane proteins?
They are located within the membrane.
p.9
Phospholipid and Sphingolipid Structures
What varies among phospholipids?
The alcohol of their head group.
p.5
Fatty Acid Classification and Properties
Why are Omega-3 and Omega-6 fatty acids considered essential?
Because they cannot be synthesized by the body and must be obtained from food.
p.11
Membrane Structure and Function
What type of lipids are ideal for forming lipid bilayers?
Amphiphilic phospholipids.
p.24
Membrane Proteins and Their Interactions
Which lipidated sites interact with basic residues in proteins?
Acidic phospholipids such as PS, PA, PIP2, and PIP3.
p.17
Types of Lipids in Membranes
List some types of lipids mentioned in the context of membrane asymmetry.
PE, PC, PS, PI, PIP, PIP2, PA, SPH.
p.14
Sphingolipid Structures
What are the functions of gangliosides?
Gangliosides serve as specific hormone receptors, receptors for bacterial protein toxins, and are important for cell-cell recognition.
p.34
Eicosanoids and Their Biological Functions
What physiological processes are influenced by eicosanoids?
Inflammation, pain perception, blood pressure regulation, and reproduction.
p.7
Fatty Acid Classification and Properties
How does the cis configuration affect the melting temperature (Tm) of fatty acids?
Cis configuration results in a lower Tm.
p.16
Membrane Dynamics and Fluidity
What can destabilization of membranes lead to?
Breakdown of permeability or involvement in fission events.
p.22
Membrane Proteins and Their Interactions
What is a single transmembrane protein?
A protein that spans the membrane once.
p.35
Membrane Proteins and Their Interactions
How have proteins evolved in relation to lipids?
To bind to and respond to certain lipids.
p.22
Membrane Proteins and Their Interactions
What is a lipid-anchored protein?
A protein attached to the bilayer solely by a covalently bound lipid chain.
p.4
Fatty Acid Classification and Properties
What are the two main criteria for classifying fatty acids?
Degree of saturation and number of carbons in their chain.
p.2
Biosynthesis of Lipids
Where does de novo biosynthesis of lipids primarily occur?
At the smooth ER of adipocytes and hepatocytes.
p.26
Membrane Proteins and Their Interactions
What effect does the number of carbons in lipidation have on membrane interaction?
More carbons in lipidation result in stronger interactions with membranes.
p.19
Membrane Dynamics and Fluidity
How does the length of acyl-chain fatty acids affect Tm?
Tm is higher with longer acyl-chain fatty acids.
p.19
Membrane Dynamics and Fluidity
What effect do unsaturated fatty acids have on Tm?
Unsaturated fatty acids lower the Tm.
p.35
Types of Lipids in Membranes
How are lipids classified?
By their backbone, fatty-acid tails, and headgroups.
p.21
Role of Cholesterol in Membranes
What are the two phases of lipids mentioned in relation to cholesterol?
Liquid disordered and liquid ordered.
p.35
Lipid Rafts and Cellular Signaling
What are 'Lipid Rafts'?
Specialized domains within membranes.
p.35
Eicosanoids and Their Biological Functions
What role do lipid enzymes play?
They allow lipids to have signaling roles.
p.32
Phospholipid and Sphingolipid Structures
What does Phospholipase D release?
Phosphatidic acid and an alcohol.
p.28
Membrane Structure and Function
What is the structure of a membrane described as?
A fluid structure with a mosaic of various proteins embedded in it.
p.10
Phospholipid and Sphingolipid Structures
List two examples of acidic phospholipids.
Phosphatidylserine (PS) and Phosphatidic acid (PA).
p.32
Phospholipid and Sphingolipid Structures
What does Phospholipase B cleave?
Both the SN-1 and SN-2 acyl chains.
p.22
Membrane Proteins and Their Interactions
Where are peripheral membrane proteins located?
At sub-membrane locations.
p.6
Fatty Acid Classification and Properties
What effect do unsaturated fatty acids have on the packing of saturated fatty acids?
They disrupt the tight packing.
p.6
Fatty Acid Classification and Properties
What is the consequence of the disruption caused by unsaturated fatty acids?
It propagates throughout the structure due to cooperative interactions between adjacent chains.
p.13
Sphingolipid Structures
How is carbon numbering different in sphingolipids compared to glycerophospholipids?
In sphingolipids, carbon 1 (C1) has the head group, not C3.
p.18
Membrane Dynamics and Fluidity
What can rapid transitions in lipid bilayers affect?
Cell functions and permeability.
p.28
Lipid Rafts and Cellular Signaling
What role do lipid rafts play in cellular processes?
They compartmentalize cellular processes, such as vesicle trafficking and signaling.
p.22
Membrane Proteins and Their Interactions
What is a β barrel?
A structure formed by a rolled-up β sheet in transmembrane proteins.
p.22
Membrane Proteins and Their Interactions
How do membrane proteins interact with each other?
Through noncovalent interactions.
p.28
Membrane Dynamics and Fluidity
What effect do increased saturated fatty acids have on membranes?
They lead to tightly packed structures.
