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BIOL 2410 Lecture Notes - Lecture 4: Membrane Transport Protein, Facilitated Diffusion, Lipid Bilayer

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grayrabbit360
15 Nov 2016
School
University of Manitoba
Department
Biological Sciences
Course
BIOL 2410
Professor
Mc Lachlan Elizabeth

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Document Summary

Types of transport proteins: channel proteins, carrier proteins. Water filled pore that can open to both sides of the cell. Provide a direct link between intra and extracellular compartments: need hydrophobic side in lipid bilayer and hydrophilic by the heads/end of proteins. Transmembrane proteins form the channel - hydrophilic segments line the pore. Carry water or ions: water channel - aquaporin. If lining of the pore is positive - repel positive ions. If lining of the pore is negative - repel negative ions. Gated channels: open and close in response to signals. Chemical gate, voltage gate, or mechanical gate. Protein that is the gate is inside the cell. Open channels: or pores are usually open. Provide an indirect link between intra and extracellular compartments, never open to both sides at once. Bind to the substrates they carry and undergo conformation change: binding of the substrate opens the carrier protein the other way. Uniport carriers: transport only one kind of substrate.

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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-­-ß
produces
phosphatidylinositol
3,4,5-­-trisphosphate
and
diacylglycerol.
(
)
(
)
2. PDGF
activates
GPCR.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
3. Rho
is
an
example
of
heterotrimeric
G
proteins.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­-
(
)
(
)
4. All
members
of
the
G
protein
coupled
receptors
interact
with
small
GTPase
Ras.
-­--­--­--­--­--­--­--­--­--­-
(
)
(
)
5. Adrenaline
is
an
example
of
the
ligands
for
the
RPTK
family.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
6. Ras
GEF
activates
RPTK.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
7. PH
domain
containing
proteins
bind
to
activated
EGFR.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
8. Ligands
for
GPCR
proteins
induce
dimerization
of
the
receptor.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
9. Grb2
is
an
adaptor
protein
that
binds
to
a
phospho-­-tyrosine
residue
of
activated
RPTK
through
a
PH
domain.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
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.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
11. PI3K
generates
phosphatidylinositol
3,4,5-­-trisphosphate
from
IP3.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
12. Calcium
inhibits
PKC.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
13. cAMP
activates
PKA.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
14. The
MAP
kinase
ERK
inhibits
MAP
kinase
kinases.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­-
(
)
(
)
15. cAMP
is
an
example
of
a
first
messenger.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
16. All
7-­-Transmembrane
receptors
are
G
Protein
Coupled
Receptors.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
17. Both
Ga
and
Gß
subunits
of
the
heterotrimeric
G
protein
can
mediate
GPCR
signaling.
-­--­--­-
(
)
(
)
18. Both
Ga
and
Gß
subunits
of
the
heterotrimeric
G
protein
have
GTPase
activity.
-­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
19. The
Gas
subunit
of
the
heterotrimeric
G
protein
suppresses
the
function
of
Adenylyl
cylase.
(
)
(

1. The plasma membrane of liver cells contains a glucose uniportthat transports glucose by facilitated diffusion. When the[glucose] is higher inside the liver cell than the [glucose]outside the liver cell, the glucose uniport will

A. couple the transport of glucose out of the cell to thehydrolysis of ATP

B. couple the transport of glucose into the cell to thehydrolysis of ATP

C. switch to a closed conformation, allowing no transport ofglucose

D. transport glucose out of the cell by passive transport

E. transport glucose in of the cell by passive transport

2. Unlike the positive charged ion shown in the middle diagramof figure 11-4B, K+ is higher in concentration inside the cell. Howwill the membrane potential of a cell at rest (shown in both themiddle and right-hand diagrams of Figure 11-4B) affect theelectrochemical gradient for K+?

A. The membrane potential will increase the electrochemicalgradient

B. The membrane potential will decrease the electrochemicalgradient

C. The membrane potential will have no effect on theelectrochemical gradient

3. Which of the following proteins carries out activetransport?

A. gluclose symport

B. Bacteriorhodopsin

C. ABC transporter

D. NA K pump

E. All of the above

4. Aquaporin will not transport Na+ ions because

A. Two asparagine residues in the channel prevent the passage ofNa+ ions by binding the oxygen of each water molecule as it passesby

B. Na+ ions are repelled by the positive charges at the entranceto the channel

C. Na+ ions cannot make contact with the carbonyl (C=O) groupson all four sides of the channel

D. The passage of Na+ ions is energetically unfavorable becauseone side of the channel is hydrophobic in nature

5. The acetylcholine receptor is different from other channelproteins we have discussed, such as the K+ leak channel,because

A. The acetylcholine channel is composed of a single polypeptiderather than multiple subunits

B. The acetylcholine channel transports Na+ ions against theconcentration gradient for sodium

C. The acetylcholine channel has a much smaller diameter thanother channel proteins

D. The acetylcholine channel transports ions with theirassociated shell of water molecules

E. The acetylcholine channel is always open, and never switchesto a closed conformation

6. After opening briefly along the axon of a neuron,voltage-gated ion channels switch to an inactivated conformationthat slowly returns to the original closed conformation of theprotein. This slow change in conformation, requiring about amillisecond, is important because

A. all of the ions that were transported across the membranewhen the ion channels were open must be actively transported backto the other side of the membrane, restoring the originalconcentration gradient, before the ion channels can open again

B. ATP hydrolysis is necessary to drive this energeticallyunfavorable change in conformation

C. it prevents the action potential from reversing direction andtraveling back toward the cell body of the neuron

D. the channel protein must be dephosphorylated in order tocomplete the transport process and return to the originalnonphosphorylated conformation

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The function of tRNA is to

Select one:

a. provide a site for polypeptide synthesis

b. transport amino acids to the ribosome

c. transcribe DNA

d. transform DNA

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The lipid bi-layer is

Select one:

a. hydrophilic

b. hydrophobic

c. hydrophilic and hydrophobic

d. depends on the surrounding medium

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Which of the following statements is FALSE?

Select one:

a. carbohydrates are generally hydrophilic molecules.

b. living things use carbohydrates for structure and for energy storage.

c. carbohydrates are composed principally of carbon, hydrogen, and oxygen.

d. none of the above – they are all true

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Which of the following terms correctly describes a compound featuring more than one double bond?

Select one:

a. saturated

b. polyunsaturated

c. monounsaturated

d. disaturated

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Eukaryotic mRNA transcripts are protected from modification by

Select one:

a. 5' caps

b. 5' poly-A caps

c. 3' caps

d. 5'-3' poly tails

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The methods of membrane transport that don't require protein channels or carriers are

Select one:

a. osmosis

b. diffusion

c. phagocytosis

d. exocytosis

e. all of the above

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Complete the following sentences: "Primary active transport is dependent on __________. Secondary active transport is dependent on __________ created by __________.

Select one:

a. channel proteins, electrochemical gradient, carrier proteins

b. electrochemical gradient, ATP, mitochondria

c. electrochemical gradient, ATP, primary active transport

d. ATP, electrochemical gradient, primary active transport

e. carrier proteins, electrochemical gradient, channel protein

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Which of the following is a reduced compound?

Select one:

a. CO2

b. O2

c. N2

d. NAD +

e. NADH

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Gel electrophoresis separates DNA fragments according to their:

Select one:

a. base sequence

b. size

c. percentage of labelled nucleotides

d. electrical charge

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G0 is:

Select one:

a. part of interphase

b. the phase of the cell cycle where DNA replication occurs

c. the phase of the cell cycle where two identical daughter cells are created

d. a special "resting" phase in which cells are in a non cycling state

e. a special phase where the number of chromosomes in a parent cell is reduced by half such that each daughter cell contains only one member of a pair of homologous chromosomes

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At which pH will the concentration of hydrogen ions be equal to the concentration of hydroxide ions?

Select one:

a. pH 1

b. pH 5

c. pH 7

d. pH 9

e. pH 14

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Which of the following enzymes has proofreading activity?

Select one:

a. Ligase

b. Helicase

c. Topoisomerase

d. DNA polymerase

e. Peptidyl transferase

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The process of _______________ cuts introns from the primary transcript and the final "processed" mRNA is produced.

Select one:

a. RNA cleaving

b. RNA translocation

c. RNA elongation

d. RNA splicing

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Transcription is initiated when RNA polymerase binds to

Select one:

a. a promoter

b. an initiator

c. a transciptor

d. a codon

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Complete the following sentences: "__________ connect the extracellular matrix with microfilaments. __________ connect intermediate filaments from adjacent cells."

Select one:

a. Cadherins, Integrins

b. Connexins, Cadherins

c. Integrins, Cadherins

d. Integrins, Connexins

e. Connexins, Integrins

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Which of the following regions of RNAs are translated?

Select one:

a. 5' UTR

b. exons

c. introns

d. 3' UTR

e. poly-A

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Control of gene expression in eukaryotic cells occurs at which level(s)?

Select one:

a. only the transcriptional level

b. epigenetic and transcriptional levels

c. epigenetic, transcriptional, and translational levels

d. epigenetic, transcriptional, posttranscriptional, translational, and posttranslational levels

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Cellular organelles containing hydrolytic enzymes are called:

Select one:

a. peroxisomes

b. lysosomes

c. ribosomes

d. mesosomes

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______ are chemicals or combinations of chemicals that take up excess hydrogen ions or hydroxide ions in order to keep the pH constant.

Select one:

a. acids

b. bases

c. salts

d. buffers

e. carbohydrates

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Which of the following proteins appear in some stages of the cell cycle and are degraded at other stages?

Select one:

a. kinases

b. cyclins

c. nucleotides

d. phosphatases

e. none of the above

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Which of the following correctly matches an organelle with its function?

Select one:

a. mitochondrion photosynthesis

b. nucleus cellular respiration

c. ribosome manufacture of lipids

d. lysosome movement

e. central vacuole storage

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What is the sequence corresponding to the following electropherogram obtained by Sanger sequencing (green: A; red:T; black: G; blue: C)?

Select one:

a. CCGTTATGAAC

b. GGCTTATGAAG

c. CAACTATTGCC

d. GGCAATAGTTG

e. CCGTTATCAAC

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Which of the following statement is true

Select one:

a. the two DNA strands are parallel and complementary

b. the two DNA strands are anti parallel and non-complementary

c. the two DNA strands are anti-parallel and complementary

d. none of these

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The energy-requiring process by which small molecules are joined to form larger molecules is specifically called

Select one:

a. metabolism

b. anabolism

c. catabolism

d. enzymatic reactions

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When DNA replication starts

Select one:

a. the phosphodiester bonds between the adjacent nucleotides break

b. the bonds between the nitrogen base and deoxyribose sugar break

c. the leading strand produces Okazaki fragments

d. the hydrogen bonds between the nucleotides of two strand break

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A(n)_______ is the movement of a segment of a chromosome from one chromosome to another nonhomologous chromosome

Select one:

a. inversion

b. translocation

c. deletion

d. duplication

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Complete the following sentences: "Replication forks from the same origin of replication extend __________. __________ DNA strand is used as template for the leading strand at one fork and for the lagging strand at the second fork. New DNA is synthesized from 5' to 3' on the __________."

Select one:

a. unidirectionally, A different, both the leading and lagging strands

b. bidirectionally, The same, leading strand

c. bidirectionally, The same, lagging strand

d. unidirectionally, A different, leading strand

e. bidirectionally, The same, both the leading and lagging strands

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Manufacturing recombinant DNA molecules involves cutting a gene from its normal location, inserting it into a circular piece of DNA from a bacterial cell, and then transferring the circle of DNA to cells of another species. Which of the below describe the circular piece of DNA?

Select one:

a. restriction enzyme

b. plasmid

c. bacteriophage

d. transposon

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Complete the following chemical equation to make it balanced: glycerol + ___ ? triacylglycerol + ___

Select one:

a. 3 fatty acid, 3 H2O

b. fatty acid, H2O

c. 3 OH-, 3 H+

d. 3 H2O, 3 fatty acid

e. fatty acid, 3 H2O

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Which structure is found in plant cells but not animal cells? Check all that apply.

Select one or more:

a. Cell wall

b. Chloroplast

c. Plastid

d. Central vacuole

e. Lysosomes