The amount of cholesterol in cell membranes varies from ~40% of lipids in the ______________ membrane to ~10% of lipids in the __________________ membranes correct answers The amount of cholesterol in cell membranes varies from ~40% of lipids in the plasma membrane to ~10% of lipids in the endoplas...
BIOC 385 Module 5 || with 100% Errorless Answers.
The amount of cholesterol in cell membranes varies from ~40% of lipids in the ______________
membrane to ~10% of lipids in the __________________ membranes correct answers The
amount of cholesterol in cell membranes varies from ~40% of lipids in the plasma membrane to
~10% of lipids in the endoplasmic reticulum membranes
What do high local concentrations of cholesterol do to phospholipids and membrane fluidity?
correct answers prevent lateral movement of phospholipids and decrease membrane fluidity
What feature of cholesterol effects membrane fluidity? correct answers its nonpolar planar rings
At low/high temperatures with more/same/less concentrations, cholesterol maintains membrane
fluidity through its disruption of fatty acid packing. correct answers At low temperatures with
same concentrations, cholesterol maintains membrane fluidity through its disruption of fatty acid
packing.
Most snake venoms contain a _______________ enzyme that causes tissue damage by releasing
free fatty acids from __________________, which function as biological detergents.
a) protein phosphatase A enzyme; triacylglycerols
b) phospholipase A2 enzyme; glycerophospholipids
c) phospholipase A2 enzyme; triacylglycerols
d) protein phosphatase A enzyme' glycerophospholipids correct answers b) phospholipase A2
enzyme; glycerophospholipids
What are the 3 major lipids in cell membranes? correct answers 1) phospholipid
(glycerophospholipids) 2) sphingolipids 3) cholesterol
What are glycerophospholipids derived from? What are the 4 major subtypes of
glycerophospholipids? correct answers derived from phosphatidate;
4 subtypes: phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine,
phosphatidylinositol
What are sphingolipids derived from? What are the 2 major subtypes of sphingolipids? correct
answers derived from sphingosine and 1 fatty acid
2 subtypes: sphingophospholipids (sphingomyelin) and sphingoglycolipids (cerebrosides)
The percentage of lipid types within the membrane lipid fraction is based on what?
a) mass
b) weight
c) density correct answers a) mass
The plasma membrane is mostly protein/lipid in terms of mass and once it is dehydrated. correct
answers The plasma membrane is mostly protein in terms of mass and once it is dehydrated.
,In membrane lipids, where do the polar groups orient towards? Where do the nonpolar tails of
fatty acids, sphingosine, and cholesterol orient towards? correct answers polar - aqueous
environment
nonpolar - hydrophobic center of the lipid bilayer
What do glycerophospholipids contain? correct answers two fatty acids and a phosphate group
attached to glycerol
What do sphingophospholipids contain? correct answers sphingosine and fatty acid which are
attached to a phosphate and choline
What do sphingoclycolipids contain? correct answers sphingosine and fatty acid which are
attached to a glycan group
In comparison with glycerophospholipids. the structure of cerebrosides contains what? correct
answers sphingosine
What does the outer monolayer of the plasma membrane in human erthryocytes contains mostly
what 2 things?
a) phosphatidylcholine and glycerophospholids
b) phosphatidylcholine and sphingolipids
c) phosphatidylphosphate and glycerophospholipids
d) phosphatidylphosphate and spingolipids correct answers b) phosphatidylcholine and
sphingolipids
What does the inner monolayer consist almost entirely of? correct answers glycerophospholipids
(phosphatidylinositol, phosphatidylethanolamine, and phosphatidylserine)
______________ are thought to be discrete membrane regions that contain high concentrations
of cholesterol and an aggregation of transmembrane receptor proteins and glycoproteins involved
in cell signaling correct answers lipid rafts
__________________________ are important sources of fatty acid-derived signaling molecules,
which are released from membrane lipids by hydrolytic cleavage reactions catalyzed by
phospholipase enzymes correct answers glycerophospholipids
What is the simplest glycerophospholipid?
a) phosphatase
b) phosophatidylserine
c) phosphatidylcholine
d) phosphatidate correct answers d) phosphatidate
What are all the very abundant glycerophospholipids? correct answers phosphatidylserine,
phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine
, Phospholipase enzymes cleave glycerophospholipids such as PIP2 by catalyzing a
______________ reaction
a) hydrolysis
b) isomerization
c) osmolysis
d) adenlylation correct answers a) hydrolysis
What does cleavage by phospholipase A2 generate? correct answers arachidonate
What does cleavage by phospholipase A1 produce? correct answers stearate
What is the core structure of all sphingolipids and consists of a sphingolipid and a fatty acid?
a) sphingomyelin
b) ganglioside
c) ceramide correct answers c) ceramide
1. __________________ is a sphingophospholipid, whereas 2.____________ is a
monoglycosylated ceramide.
a) 1. ceramide, 2. ganglioside
b) 1. sphingomyelin, 2. cerebroside
c) 1. cerebroside, 2. sphingomyelin
d) 1. sphingomyelin, 2. ganglioside correct answers b) b) 1. sphingomyelin, 2. cerebroside
What is a ceramide with an oligosaccharide moiety?
a) ganglioside
b) sphingomyelin
c) ceramide correct answers a) ganglioside
Sphingoside is synthesized from what 2 things?
a) palmitate and stearate
b) palmitate and proline
c) phosphocholine and stearate
d) proline and stearate correct answers a) palmitate and stearate
Tay-Sachs disease is caused by a defect in the enzyme _____________________. This leads to a
build up of what? correct answers enzyme hexosaminidase A, leading to a buildup of the GM2
ganglioside
Fabry disease is caused by defects in 1.________________________ and the accumulation of
2._____________________
a) 1. hexosaminidase A, 2. GM2 ganglioside
b) 1. sphingomyelinase, 2. GM2 ganglioside
c) 1. alpha-galactosidase A, 2. ceramide trihexoside
d) 1.sphingomyelinase, 2. ceramide trihexoside correct answers c) 1. alpha-galactosidase A, 2.
ceramide trihexoside
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