Biochemistry: membranes (integrated II)

Boundaries, import/export, sense external signals, store energy as proton gradient, support synthesis of ATP

Functions of membranes

Michelle’s, belayer, liposomes

3 main structure that lips form

Neutral

What kind of polarity does triglycerides have

Polar

What polarity do phospholipids have

Amphipathic lipids (phospholipids or glycolipids)

What are Micelles form with

Phospholipids and sphingolipids

What form the membrane belayer

Small lipid bilayers

What are liposomes make of

Function as vesicles to carry hydrophilic molecules (polar)

What is the function of liposomes

Glycerol back bone and 3 fatty acids

Components of triglycerides

Phospholipids and glycolipids

What type of lipids are amphipathic

Cholesterol, sphingolipids, and phosphatidylcholine

3 major components of membranes

Serve as pump, gates, receptors, energy transducers, and ENZYMES

What types of function do membrane proteins have

Phosphoglycerides and sphingolipids (sphingomyelin)

What are the subcategories of phospholipids

Glycerol back bone, 2 fatty acids, and a phosphorylated alcohol

What are phosphoglyerides composed of

Phosphatidylserine, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine

Types of phosphoglycerides

A sphingosine backbone, 1 fatty acid, and a phosphorylated choline

What are sphingolipids composed of

Sphingomyelin

What is the most common sphingolipids

Glycerol back bone, 1 or 2 fatty acids, and covalently bound sugar

What are the components of glycolipids

It’s polar head group (OH)

What dictates the reactivity of cholesterol and makes it amphipathic

Small polar solutes and non polar compounds

What are membrane permeable to

Large polar solutes and ions

What are membranes impermeable to

The free energy barrier (proton gradient)

What prevents membrane proteins from rotating

Peripheral (non GPI linked), Amphitrophic and GPI linked, and integral

What are the 3 types of membrane proteins

Proteins located on the surface of the membrane and can easily dissociated from membrane during changes in ionic strength like pH change

What are peripheral (non GPI liked) membrane proteins

Proteins located on the membrane surface that are linked during specific regulatory events and can reversibly be removed

What are Amphitrophic and GPI linked membrane proteins

Proteins that extend through the membrane on either side and can only be removed using strong detergents

What are integral membrane proteins

The polar head groups of the membrane through ionic interactions

What do peripheral proteins associate with

Covalently interact with lipids or carbohydrates attached to lipids

What do Amphitrophic membrane proteins associate with

The hydrophobic region of the membrane

What does the integrate membrane protein associate with

They still have phospholipids associated with them

What happens with integral membrane proteins are purified

Alpha helix, anion channels are formed by several of these alpha helicies

What does the transmembrane region of the integral membrane protein consist of

The 7 helix motif

The most common transmembrane receptor

A plot that indicates the hydrophobic regions of a transmembrane region

What is a hydropathy plot

Prevents RBC from adhering to other cells and blood vessel walls

The benefits of a high glycosylated membrane

Phosphatidylcholine and sphingomyelin

Outer layer of RBC consist of

Phosphatidylethanolamine, phosphoinositol, phosphatidylserine

Inner layer of RBC consists of

Macrophage will phagocytose the RBC

What happens if phosphatidylserine is exposed on the outer membrane of a RBC

Increase double bonds, and shorter fatty acids tails

What makes a membrane more fluid

More unsaturated fatty acid tails and longer fatty acid tails

What makes a membrane more gel like

Transmembrane linker protein that bind to extracellular matrix proteins and micro filaments of the cytoskeleton via intracellular attachment proteins

What are integrins

Alpha subunit and beta subunits that interact in a non-covalent manner

What are integrins composed of

Helps define cell-specific properties and cell to cell interactions

Main function of diverse integrins

They produced less fibronectin so there are less integrins to attach them to extracellular matrix. This allows them to travel in the body allowing it to metastasize

Issue with transformed (cancer like) cells