Biochem 1- Chapter 12

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What term describes molecules that have both hydrophilic and hydrophobic moieties?

amphipathic

glycolipids

carbohydrate containing lipid derived from sphingosine where the carbohydrate is linked to the primary alcohol of sphingosine

phospholipids

include 4 components: fatty acid, a platform, a phosphate, and an alcohol

What is the most common process by which lipids and proteins move in the membrane bilayer?

lateral diffusion

Fatty acids can be saturated or unsaturated

saturated = single bonds unsaturated = double bonds

What important property is conferred on membranes by transport systems?

selective permeability

what ion characteristics move through membranes easiest?

smaller and more polar

What is the number of carbons found in the most commonly observed fatty acids?

16 or 18

name fatty acids for the#C:#double bonds

18:0 is octadecanoic acid (octadecane) 18:1 is octadecenoic acid 18:2 is octadecadienoic acid

How many molecules thick are membranes?

2

Which of the following statements is consistent with the structure of biological membranes

The membrane lipids self-assemble to form the lipid bilayer

) Which of the following membranes would be the most fluid?

a bilayer made of lipids with polyunsaturated 16 carbon-fatty acids

The most common motif found in membrane spanning proteins is

a helices of nonpolar amino acids that pass through the membrane

What substance inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels?

acetylsalicylic acid

cholesterol helps maintain fluidity in membranes

acts as a buffer system

cerebrosides

are the simplest glycolipids, containing only one sugar

In addition to phospholipids and glycolipids, which of the following is a major type of membrane lipid?

cholesterol

Which of the following helps regulate membrane fluidity in animals?

cholesterol

when double bonds are present, they are commonly in the -- configuration

cis

What protein polymerizes into a lattice network around a budding membrane?

clathrin

amphipathic molecules

containing hydrophobic and hydrophilic regions

fatty acids in biological systems usually contain _____ number of carbon atoms:

even

What membrane components contain carbohydrates?

glycolipids

2 common platforms in phospholipids

glyercol (phosphoglycerides/phosphoglycerols) and sphingosine

What property is used to determine the probability that a segment of a protein will be found embedded in a membrane?

hydropathy

fatty acids

key constituents of lipids named based on their parent hydrocarbons chains of H-bearing carbon atoms that have a carboxylic acid at one end and a methyl group at the other end

cholesterol

lipid based on a steroid nucleus with the attachment of a fatty acid on one side and hydroxyl group on the other. The hydroxyl group interacts with phospholipid heads

What complex is observed between cholesterol and membrane phospholipids?

lipid raft

Membranes are primarily comprised of

lipids & proteins.

short chain fatty acids have a --- melting temperature than long chain fatty acids with the same saturation

lower

unsaturated fatty acids have a --- melting temperature than saturated fatty acids of the same C chain length

lower

The low incidence of protein or lipid flip-flop in a membrane preserves

membrane asymmetry.

Which of the following membrane-bound organelles is thought to have evolved from bacteria by endosymbosis?

mitochondria

2 different naming systems

one starts as C 2 and 3 are alpha, beta other starts at methyl C as omega

Carbohydrate residues attached to the membrane lipids are almost always

positioned on the extracellular side of the membrane

gangliosides

type of sphingolipids (sphingosine or sphingoid backbone) GLYCOLIPIDS glycosidic linages - no phosphate grou; polar head group is oligosaccharides with one or more *N-acetylneuramanic acid (NANA/stalic acid)* at the terminus this contains a *negative charge* play a role in cell interaction, recognition, and signal transduction

The degree of membrane fluidity in bacteria depends mainly on the percentage of

unsaturated fatty acids.

What force(s) stabilize(s) the lipid bilayers?

van der Waals interactions and electrostatic and hydrogen bonding between the polar heads and surrounding water


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