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MICI 3119 Lecture Notes - Lecture 3: Cell Envelope, Lipid Bilayer, Cell Membrane

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5 Feb 2018

School

Dalhousie University

Department

Microbiology & Immunology

Course

Professor

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Document Summary

Outline: outer membrane, lps, porins, braun(cid:2)s lipoprotein, periplasm. Outer membrane (om: primarily functions as a permeability barrier - selective barrier. Om is not as permeable to hydrophobic molecules as the cytoplasmic membrane(cm) Allows passage of hydrophilic molecules through porins: confers negative charge on bacteria, phage receptors (o-antigen and ompa, has the typical appearance of a "unit membrane", i. e. , a lipid bilayer (-8 nm thick), and is composed of: Lipopolysaccharide (lps) found only in outer leaflet of om. Lipoprotein (braun"s,) which is also associated with the peptidoglycan. Lipopolysaccharides (lps: also referred to as endotoxin/pyogen. Lipid a contains toxic activity (minor: cytokine induction; major: hypotension, septic shock). Elicits strong immune responses in mammals: functions: Confers negative charges and repels hydrophobic molecules. Repels fat soluble molecules such as bile that the gal bladder secretes. O-specific polysaccharide (o- antigen: varies in length and composition. "head" composed of 2 molecules of n- acetylglucosamine phosphates joined by a.

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Related Questions

True or False? True False
1. Proteins rapidly pass artificial membrane (liposome).--------------------------------------------------------------------------------------( ) ( )
2. Amphiphatic detergent such as SDS spontaneously forms bilayer inwater. ------------------------------------------------------------( ) ( )
3. Cholesterol does have a hydrophilic head and hydrophobic tail.-------------------------------------------------------------------------( ) ( )
4. Fat molecules are one of the major components of the plasmamembrane.------------------------------------------------------------- ( ) ()
5. Phospholipid molecules such as phosphatidylcholine spontaneouslyform bilayer. ----------------------------------------------------( ) ( )
6. Flippase facilitates lateral movement of phospholipids withinthe plane of the membrane.----------------------------------------- ( ) ( )
7. Glycolipids make bilayer less permeable to small water solublemolecules.----------------------------------------------------------- ( ) ()
8. Membrane inner leaflet is enriched with phosphatidylcholine,Sphingomyelin, and Glycolipid. -----------------------------------( ) ( )
9. Plasma membrane proteins can have an enzyme activity.--------------------------------------------------------------------------------( ) ( )
10. A single pass membrane protein must have an amphiphatic alphahelix.-------------------------------------------------------------- ( )( )
11. Plasma membrane proteins can be linked to a lipid molecule atthe outer leaflet of the plasma membrane. --------------------- ( )( )
12. The lateral motility of membrane proteins can be restricted bytight junctions.------------------------------------------------------ ( ) ()
13. Channel proteins have specific binding sites for ions and thusslower than carrier proteins.--------------------------------------- ( ) ( )
14. An antiport would function as a symport if its orientation inthe membrane were reversed. ---------------------------------------( ) ( )
15. A transmembrane pore can be formed by multiple amphipathicalpha helices. ----------------------------------------- ( ) ()
16. Porin proteins form water-filled channels in the outer membraneof a bacterium and are mostly composed of beta sheets. ---- ( ) ()
17. Glucose uniporters localize at the apical side of theintestinal epithelium.------------------------------------------------------------ ( ) ()
18. GAP junction is a selective pore for anions.-----------------------------------------------------------------------------------------------( ) ( )
19. A voltage-gated Na+ channel adopts only two conformationstates: open and closed.----------------------------------------------- ( ) ( )
20. Voltage gated K+ channel opens faster than the Voltage gatedNa+ channels.-------------------------------------------------------- ( ) ()
21. Opening of chloride channel at the synapse will help to fire anaction potential.------------------------------------------------------ ( ) ()
22. The nuclear pore complex forms a gate through which moleculespass the nucleus uni-directionally. -------------------- ( ) ()
23. A completely folded protein is imported into a mitochondrionthrough a large non-selective pore.--------------------------------- ( ) ( )
24. ER signal sequence contains multiple lysine and arginineresidues.----------------------------------------------------------------------( ) ( )
25. The plasma membrane is a sorting station of inward endocyticpathway.---------------------------------------------------------------- () ( )
26. The trans Golgi functions as a sorting station of outwardsecretory pathway.----------------------------------------------------------- ( ) ()
27. Vesicles budding from ER are coated with Clathrin.----------------------------------------------------------------------------------------( ) ( )
28. RabGTPases and tethering proteins are the major specificitydeterminant of vesicle transport system. --------------------------( ) ( )
29. v-SNARE proteins are one of the tethering proteins.------------------------------------------------------------------------------------( ) ( )
30. In secretory cells, the constitutive and regulatory pathways ofexocytosis diverge at the cis Golgi network. ------------------ ( )( )
31. Many proteins are posttranslationally glycosylated at tyrosineresidues in the ER.------------------------------------------------- ( ) ( )
32. Cells import LDL molecules exclusively through pinocytosis.-------------------------------------------------------------------------( ) ( )
33. Cells recycle LDL receptors from lysosome to the plasmamembrane.----------------------------------------------------------------- () ( )
34. Phagosomes fuse with late endosome.------------------------------------------------------------------------------------------------------( ) ( )
35. Small vesicles from ER near the plasma membrane can fuse withthe plasma membrane upon bypassing Golgi apparatus. -- ( ) ()
36. If a Sec mutant showed an accumulation of newly synthesizedproteins at ER,
then the Sec gene is likely a component of vesicle-buddingmachinery of trans-Golgi network.------------------------------------ ( ) ( )
37. A signal recognition particle is a single pass trans-membraneprotein of the ER membrane.---------------------------------------- ( ) ( )
38. Typical animals cells display higher levels of intracellularsodium than extracellular compartments.------------------------------ ( ) ( )
39. Typical animals cells display higher levels of intracellularchloride than extracellular compartments.----------------------------- ( ) ( )
40. The Na-K Pump is a GTPase that can adopt active and inactiveconformational states.----------------------------------------------- ( ) ( )
1. Phospholipase
C-Â-Ã
produces
phosphatidylinositol
3,4,5-Â-trisphosphate
and
diacylglycerol.
(
)
(
)
2. PDGF
activates
GPCR.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
3. Rho
is
an
example
of
heterotrimeric
G
proteins.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â-
(
)
(
)
4. All
members
of
the
G
protein
coupled
receptors
interact
with
small
GTPase
Ras.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
5. Adrenaline
is
an
example
of
the
ligands
for
the
RPTK
family.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
6. Ras
GEF
activates
RPTK.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
7. PH
domain
containing
proteins
bind
to
activated
EGFR.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
8. Ligands
for
GPCR
proteins
induce
dimerization
of
the
receptor.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
9. Grb2
is
an
adaptor
protein
that
binds
to
a
phospho-Â-tyrosine
residue
of
activated
RPTK
through
a
PH
domain.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
10. When
a
cell
is
expressing
a
large
number
of
dominant
negative
EGFR
proteins,
an
introduction
of
a
constitutively
active
Ras
mutant
will
allow
EGF
signaling.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
11. PI3K
generates
phosphatidylinositol
3,4,5-Â-trisphosphate
from
IP3.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
12. Calcium
inhibits
PKC.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
13. cAMP
activates
PKA.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
14. The
MAP
kinase
ERK
inhibits
MAP
kinase
kinases.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â-
(
)
(
)
15. cAMP
is
an
example
of
a
first
messenger.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
16. All
7-Â-Transmembrane
receptors
are
G
Protein
Coupled
Receptors.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
17. Both
Ga
and
GÃ
subunits
of
the
heterotrimeric
G
protein
can
mediate
GPCR
signaling.
-Â--Â--Â-
(
)
(
)
18. Both
Ga
and
GÃ
subunits
of
the
heterotrimeric
G
protein
have
GTPase
activity.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
19. The
Gas
subunit
of
the
heterotrimeric
G
protein
suppresses
the
function
of
Adenylyl
cylase.
(
)
(