Exam 2 Quizes Flashcards
The myelin sheath is contains a high content of a particular glycolipid called ____.
A) phosphatidylinositol
B) blood-group antigens
C) monogalactosyl diacylglycerol
D) galactocerebroside
E) ganglioside GM3
galactocerebroside
Two unsaturated fatty acids, EPA and DHA, are incorporated primarily into ___ of membranes in the brain and retina.
A) phosphatidylethanolamine and phosphatidylcholine
B) phosphatidylserine and phosphatidylinositol
C) ceramide and sphingomyelin
D) cerebroside and ganglioside
E) cholesterol and cardiolipin
phosphatidylethanolamine and phosphatidylcholine
Which of the following membranes has the highest lipid to protein ratio?
A) outer mitochondrial membrane
B) red blood cell plasma membrane
C) inner mitochondrial membrane
D) myelin sheath
myelin sheath
Which of the following is the most abundant lipid in human red blood cells?
A) phosphatidic acid
B) phosphatidylcholine
C) glycolipids
D) cholesterol
E) sphingomyelin
phosphatidylcholine (nope) sphingomyelin (nope)
A person having blood type B has an enzyme that adds ____ to the end of the oligosaccharide chain of the glycolipid antigen.
A) acetyl groups
B) N-acetylgalactosamine
C) galactose
D) phosphate
E) amino acids
galactose
GPI-anchored proteins are bound to the membrane by an oligosaccharide linked to ____.
A) phosphatidylinositol
B) serine or threonine
C) N-acetylgalactosamine
D) galactose
E) asparagine
phosphatidylinositol
Which of the following membranes has the highest protein to lipid ratio?
A) outer mitochondrial membrane
B) inner mitochondrial membrane
C) red blood cell plasma membrane
D) myelin sheath
inner mitochondrial membrane
Which of the following are not amphipathic?
A) diglycerides
B) phospholipids
C) cholesterol
D) triglycerides
E) phosphoglycerides
triglycerides
The only phospholipid of the membrane that is not built with a glycerol backbone is
A) phosphatidylinositol
B) lecithin
C) sphingomyelin
D) cephalin
E) cardiolipin
sphingomyelin
Phosphatidylcholine dispersed in an aqueous solution can assemble spontaneously to form the walls of fluid filled spherical vesicles called ____.
A) lysosomes
B) liposomes
C) chromosomes
D) peroxisomes
E) ribosomes
liposomes
Which of the following is concentrated in the inner leaflet of the membrane?
A) cholesterol
B) glycolipids
C) phosphatidylcholine
D) sphingomyelin
E) phosphatidylethanolamine
phosphatidylethanolamine
Amino acid residues in transmembrane domains form _____ with the fatty acyl chains of the lipid bilayer.
A) van der Waals interactions
B) weak electrostatic bonds
C) glycosylphosphatidylinositol linkage
D) N-glycosidic linkage
E) temporary peptide bonds
van der Waals interactions
Membranes are lipid-protein assemblies in which the components are held together by ____.
A) ionic bonds
B) peptide bonds
C) glycosidic bonds
D) noncovalent bonds
E) hydrogen bonds
noncovalent bonds
Which of the following is virtually absent in most membranes?
A) phosphatidylserine
B) phosphatidylcholine
C) phosphatidylinositol
D) phosphatidic acid
E) phosphatidylethanolamine
phosphatidic acid
Galactocerebroside is formed when galactose is added to ____.
A) ceramide
B) sphingomyelin
C) ganglioside
D) sphingosine
E) cerebroside
ceramide
Which of the following is the most abundant lipid in beef heart mitochondria?
A) glycolipids
B) phosphatidylcholine
C) phosphatidic acid
D) sphingomyelin
E) cholesterol
phosphatidylcholine
A person having blood type A has an enzyme that adds ____ to the end of the oligosaccharide chain of the glycolipid antigen.
A) galactose
B) acetyl groups
C) amino acids
D) N-acetylgalactosamine
E) phosphate
N-acetylgalactosamine
Peripheral proteins are associated with the membrane by ____.
A) van der Waals interactions
B) weak electrostatic bonds
C) glycosylphosphatidylinositol linkage
D) N-glycosidic linkage
E) temporary peptide bonds
weak electrostatic bonds
Membranes are highly permeable to _____.
A) dissolved ions
B) phosphorylated intermediates
C) amino acids
D) water
E) sugars
water
When a cell is placed into a/n ____ solution, the cell rapidly gains water by osmosis and swells.
A) hypotonic
B) hypertonic
C) neutral
D) acidic
E) basic
hypotonic
A family of small integral proteins, called ____, allow the passive movement of water from one side of the plasma membrane to the other.
A) exchangers
B) aquaporins
C) ion channels
D) active transporters
E) facilitative transporters
aquaporins
A gradient favoring the continued diffusion of glucose into skeletal muscle cells is maintained by _____.
A) oxidative phosphorylation
B) glycolysis
C) Na+/glucose cotransporter
D) facilitative glucose transporter
E) plasmolysis
glycolysis
Digitalis, which is used to treat congestive heart disease, binds to the ____.
A) H+/sucrose cotransporter
B) Na+/glucose cotransporter
C) H+/K+-ATPase
D) Na+/K+-ATPase
E) K+ channel
Na+/K+-ATPase
Prilosec and related drugs are widely used to prevent heartburn by inhibiting the stomach’s ____.
A) Na+/K+-ATPase
B) H+/sucrose cotransporter
C) Na+/glucose cotransporter
D) K+ channel
E) H+/K+-ATPase
H+/K+-ATPase
The ratio of a solute’s solubility in a nonpolar solvent to that in water, when the nonpolar solvent and water are mixed together, is known as its _____.
A) dissociation constant
B) membrane permeability
C) electrochemical gradient
D) partition coefficient
E) equilibrium constant
partition coefficient
Water moves through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration. This process is known as ____.
A) active transport
B) passive diffusion
C) facilitated diffusion
D) osmosis
osmosis
The conformational state of a/n ____ depends on the binding of a specific molecule, which is usually not the solute that passes through.
A) voltage-sensing domain
B) facilitative transporter
C) enzyme inhibitor
D) selectivity filter
E) ligand-gated channel
ligand-gated channel
A small inactivation peptide dangles from the small cytoplasmic portion of _____.
A) facilitative glucose transporters
B) bacteriorhodopsin
C) eukaryotic Kv channels
D) Na+/glucose cotransporter
E) Na+/K+-ATPase
eukaryotic Kv channels
Bacteriorhodopsin contains ___, which is the same prosthetic group in the light-absorbing protein of the rods of the retina.
A) chlorophyll
B) aspartic acid
C) rhodopsin
D) retinal
E) heme
retinal
The transport of sucrose in a plant cell are examples of symport, in which the two transported species, _____, move in the same direction.
A) Na+ and glucose
B) Na+ and sucrose
C) glucose and sucrose
D) H+ and sucrose
E) H+ and glucose
H+ and sucrose
For a nonelectrolyte to diffuse passively across a plasma membrane, which of the following conditions must be met:
1. the substance must be present at a higher concentration on one side of the membrane than the other
2. the substance must be able to pass directly through the lipid bilayer
3. the substance must be able to traverse the aqueous pore that spans the membrane
4. the substance must dissolve in the lipid bilayer on its way through the membrane
5. the membrane must be permeable to the substance
A) 4 and 5
B) 1 and 2
C) 1 and 5
D) 2 and 3
E) 2 and 4
1 and 5
Plant cells are generally hypertonic compared to their fluid environment so water has a tendency to enter the cell, causing it to develop a/n _____ that pushes against its surrounding wall.
A) turgor pressure
B) plasmolysis
C) conductance
D) selectivity filter
E) electrochemical gradient
turgor pressure
Most ion channels can exist in open or closed conformation; such channels are said to be ____.
A) saturable
B) gated
C) clamped
D) semipermeable
E) selective
gated
Eukaryotic cells generate steep concentration gradients across its plasma membrane by ____.
A) facilitated diffusion
B) active transport
C) photosynthesis
D) osmosis
E) simple diffusion
active transport
During the pumping cycle, hydrolysis of ATP leads to the transfer of the released phosphate group to an aspartic acid residue of the ___.
A) ATP-binding cassette transporter
B) cotransporter
C) V-type pump
D) ATP synthase
E) P-type pump
P-type pump
The movement of glucose across the apical plasma membrane of epithelial cells, against a concentration gradient, occurs by cotransport with ___.
A) K+
B) electrons
C) protons
D) water
E) Na+
Na+
The plasma membrane contains ___ that mediate interactions between the cell and the components of its environment.
A) receptors
B) adaptors
C) collagen
D) laminins
E) proteoglycans
receptors
In the kidney, blood is filtered through a double-layered ____ that separates the capillaries of the glomerulus from the wall of the kidney tubules.
A) basement membrane
B) glycocalyx
C) extracellular matrix
D) epidermis
E) dermis
basement membrane
Tendons contain an ECM in which the ____ are aligned parallel to the long axis of the tendon, thus parallel to the direction of pulling forces.
A) primordial germ cells
B) interconnected fibronectin molecules
C) neural crest cells
D) collagen fibrils
E) nonsulfated GAGs
collagen fibrils
Primordial germ cells traverse surfaces that are particularly rich in _____.
A) laminin
B) glycosaminoglycans
C) fibronectin
D) collagen
E) integrin
laminin
Platelet aggregation requires aggregation of integrin with _____.
A) fibrinogen
B) myosin
C) actin
D) talin
E) keratin
fibrinogen
Mechanotransduction is thought to be mediated by conformational changes in adaptor proteins such as ____.
A) actin
B) integrin
C) keratin
D) myosin
E) talin
talin
The outer layer of the skin consists of closely packed cells attached to one another and to an underlying noncellular layer called the ____.
A) basement membrane
B) specialized contacts
C) fibroblast
D) dermis
E) epithelial tissue
epithelial tissue (No)
dermis (No)
basement membrane (maybe)
____ is/are required as a coenzyme by the enzymes that add hydroxyl groups to amino acids of collagen.
A) glycosaminoglycans
B) RGD sequence
C) hyaluronic acid
D) ascorbic acid
E) proline
ascorbic acid
Proteoglycans consist of a core protein molecule to which chains of ____ are covalently attached.
A) primordial germ cells
B) collagen fibrils
C) interconnected fibronectin molecules
D) glycosaminoglycans
E) matrix metalloproteinases
glycosaminoglycans
Proteoglycans may be assembled into gigantic complexes by linkage of their core proteins to _____.
A) chondroitin sulfate
B) keratin
C) keratan sulfate
D) ascorbic acid
E) hyaluronic acid
hyaluronic acid
Degradation of extracellular materials is accomplished by _____.
A) matrix metalloproteinases
B) fibroblasts
C) fibrinogen
D) focal adhesions
E) hemidesmosomes
matrix metalloproteinases
Filaments of focal adhesions consist of ___, while those of hemidesmosomes consist of ___.
A) plasma membrane, basement membrane
B) integrins, intermediate filaments
C) fibronectin, myosin
D) actin, keratin
E) adaptor proteins, integrins
actin, keratin
Many types of animal cells produce an organized network of secreted molecules that provides scaffolding to the cells and tissues it surrounds. This network is called the ____.
A) dermis
B) epidermis
C) glycocalyx
D) basement membrane
E) extracellular matrix
extracellular matrix
Hydroxylated _____ is/are important in maintaining the stability of the collagen triple helix.
A) ascorbic acid
B) proline
C) glycosaminoglycans
D) RGD sequence
E) hyaluronic acid
proline
The thick middle layer of the cornea contains relatively short ____ that are organized into distinct layers.
A) neural crest cells
B) nonsulfated glycosaminoglycans
C) collagen fibrils
D) interconnected fibronectin molecules
E) primordial germ cells
collagen fibrils
Neural crest cells migrate out of the developing nervous system through pathways rich in _____.
A) primordial germ cells
B) glycosaminoglycans
C) matrix metalloproteinases
D) collagen fibrils
E) interconnected fibronectin molecules
interconnected fibronectin molecules
Separation of the alpha and beta subunits of integrins is accomplished by _____.
A) talin
B) fibroblasts
C) matrix metalloproteinases
D) actin
E) fibrinogen
talin
The cytoplasmic domains of intergrins contain binding sites for ___ that link integrins to the cytoskeleton.
A) receptors
B) adaptors
C) contactile proteins
D) actin filaments
E) keratin filaments
adaptors
Oligosaccharides of variable length that project outward from the plasma membrane form part of the _____.
A) dermis
B) epidermis
C) glycocalyx
D) extracellular matrix
E) basement membrane
glycocalyx
Collagen is the single most abundant protein in the human body, and is primarily produced by the _____.
A) basement membrane
B) extracellular matrix
C) matrix metalloproteinases
D) fibroblasts
E) cell coat
fibroblasts
Antibodies are a type of protein called a/n _____.
A) selectin
B) cadherin
C) antigen
D) catenin
E) immunoglobulin
immunoglobulin
The cytoplasmic domain of classical cadherins are often associated with ___.
A) talin
B) claudins
C) desmogleins
D) catenins
E) connexin
catenins
In the autoimmune disease pemphigus vulgaris, antibodies are produced against one of the _____, which leads to loss of epidermal cell-to-cell adhesion and blistering of thes skin.
A) cadherins
B) catenins
C) selectins
D) integrins
E) proteoglycans
cadherins
___ are cytoplasmic channels between adjacent plant cells that allow free passage of solute molecules.
A) plasmodesmata
B) ion channels
C) tight junctions
D) gap junctions
E) adherens junctions
plasmodesmata
Tight junctions are composed of a protein called occludin and a family of proteins called ___.
A) connexins
B) expansins
C) claudins
D) integrins
E) catenins
claudins
Which of the following are cell adhesion molecules associated with focal adhesions?
A) actin filaments
B) intermediate filaments
C) integrins
D) immunoglobulins
E) cadherins
integrins
Integrins on the surface of leukocytes bind to ____ on the endothelial lining of certain blood vessels.
A) collagen
B) carbohydrate ligands
C) selectins
D) IgSF proteins
E) cadherins
selectins (no)
carbohydrate ligands (no)
Selectins on the surface of lymphocytes bind to ____ on the endothelial lining of venules of peripheral lymph nodes.
A) IgSF proteins
B) collagen
C) cadherins
D) carbohydrate ligands
E) selectins
carbohydrate ligands
____ activate or inhibit their targets by phosphorylation.
A) G proteins
B) Protein kinases
C) Contractile proteins
D) Matrix metalloproteinases
E) Movement proteins
Protein kinases
____ activate or inhibit their targets by physical interaction.
A) Contractile proteins
B) Protein kinases
C) Matrix metalloproteinases
D) Movement proteins
E) G proteins
G proteins
Gap junctions are composed entirely of an integral membrane protein called ___.
A) expansin
B) plakoglobin
C) connexin
D) desmoplakin
E) desmocollin
connexin
Which of the following are cytoskeletal elements associated with adherens junctions?
A) intermediate filaments
B) integrins
C) actin filaments
D) cadherins
E) immunoglobulins
actin filaments
___ is a general term for a compound that binds to specific carbohydrate groups.
A) Cadherin
B) Immunoglobulin
C) Lectin
D) Effector
E) Mediator
Lectin
The cytoplasmic domain of desmosomal cadherins are often associated with ___.
A) G proteins
B) protein kinases
C) intermediate filaments
D) the desmotubule
E) actin filaments
intermediate filaments
Cells of the immune system are able to pass across the blood-brain barrier through _____.
A) tight junctions
B) plasmodesmata
C) ion channels
D) gap junctions
E) adherens junctions
tight junctions
In an adherens junction, cells are held together by linkages between ____.
A) integrins
B) selectins
C) catenins
D) immunoglobulins
E) cadherins
cadherins
Opening and closing of ___ can be controlled by phosphorylation and dephosphorylation of connexin subunits, as well as changes in the voltage.
A) ion channels
B) tight junctions
C) plasmodesmata
D) adherens junctions
E) gap junctions
gap junctions
Which of the following are cytoskeletal elements associated with hemidesmosomes?
A) cadherins
B) selectins
C) intermediate filaments
D) immunoglobulins
E) actin filaments
intermediate filaments
____ contributes to the formation of the extracelullar matrix and the plasma membrane.
A) Dislocation
B) Constitutive secretion
C) Co-translational translocation
D) Endocytosis
E) ER-associated degradation
Constitutive secretion
The rough ER is defined by the presence of ____ bound to its cytosolic surface.
A) ribosomes
B) sorting signals
C) positively charged amino acid residues
D) cisternae
E) oxygenases
ribosomes
The addition of sugars to the _____ residues of proteins begins in the rough ER and continues in the Golgi complex.
A) hydrophobic
B) serine and threonine
C) positively charged
D) asparagine
E) N-terminal
asparagine
During co-translational translocation, the nascent polypeptide moves from the ribosome to the ER lumen through the ___.
A) GET pathway
B) interaction between the SRP and SRP receptor
C) removal of the remaining glucose by glucosidase II
D) phosphorylation of eIFalpha
E) translocon
translocon
____ removes the N-terminal portion of a nascent polypeptide by proteolytic cleavage.
A) Phosphomannose isomerase
B) Dolichol phosphate
C) Signal peptidase
D) Oligosaccharyltransferase
E) Protein disulfide isomerase
Signal peptidase
The formation and rearrangement of disulfide bonds is catalyzed by ____.
A) glucosidase II
B) protein disulfide isomerase
C) signal peptidase
D) phosphomannose isomerase
E) oligosaccharyltransferase
protein disulfide isomerase
As the nascent polypeptide is translocated into the ER lumen, a block of sugars is transferred by oligosaccharyltransferase from ___ to the polypeptide.
A) asparagine
B) N-acetylglucosamine
C) N-acetylglucosamine 1-phosphate
D) mannose
E) dolichol phosphate
dolichol phosphate
Calnexin, calreticulin and BiP are examples of ___
A) integral membrane proteins
B) motor proteins
C) G proteins
D) reticulons
E) chaperones
chaperones
Membrane proteins of the peroxisomes come from the _____.
A) mitochondria
B) endoplasmic reticulum
C) plasma membrane
D) cytosol
E) nucleus
cytosol
The curvature of the smooth endoplasmic reticulum is induced and maintained by _____.
A) active transporters
B) tail-anchored proteins
C) chaperones
D) reticulons
E) motor proteins
reticulons
Secretory proteins contain a/n _____ at their N-terminus that directs the emerging polypeptide and ribosome to the ER membrane.
A) asparagine residue
B) sorting signal
C) nascent polypeptide
D) signal recognition particle
E) hydrophobic transmembrane segment
sorting signal
Tail-anchored proteins lack a signal sequence yet are able to go into the ER through the ___.
A) removal of the remaining glucose by glucosidase II
B) GET pathway
C) interaction between the SRP and SRP receptor
D) phosphorylation of eIFalpha
E) translocon
GET pathway
Both the SRP and SRP receptors are ___ that interact with one another in their GTP-bound states.
A) motor proteins
B) lipid-transfer proteins
C) G proteins
D) membrane-bending proteins
E) tail-anchored proteins
G proteins
Some phospholipids move from one leaflet of the membrane to another through the action of enzymes called ____.
A) lipid-transfer proteins
B) glycosyltransferases
C) flippases
D) oxygenases
E) motor proteins
flippases
The addition of sugars to an oligosaccharide chain is catalyzed by a large family of membrane-bound enzymes called _____
A) motor proteins
B) lipid-transfer proteins
C) glycosyltransferases
D) flippases
E) oxygenases
glycosyltransferases
Misfolded proteins are transported from the ER into the cytosol by ____.
A) active transport
B) endocytosis
C) facilitated diffusion
D) dislocation
E) co-translational translocation
dislocation
Transport vesicles move through the cytoplasm in a directed manner, often pulled by ____.
A) active transporters
B) motor proteins
C) chaperones
D) reticulons
E) tail-anchored proteins
motor proteins
Detoxification of ethanol and barbiturates in the SER of liver cells is carried out by ____.
A) protein disulfide isomerase
B) glycosyltransferases
C) oligosaccharyltransferase
D) signal peptidase
E) oxygenases
oxygenases
Proteins synthesized on ribosomes attached to RER membranes are released into the ER lumen in a process called _____.
A) co-translational translocation
B) endocytosis
C) ER-associated degradation
D) constitutive secretion
E) dislocation
co-translational translocation
Polypeptides that undergo co-translational translocation contain a signal sequence that is recognized by a ____.
A) SRP receptor
B) tail-anchored protein
C) signal recognition particle
D) translocon
E) GTP-binding protein
signal recognition particle
Carbohydrates are added to the nascent protein by the enzyme ____.
A) signal peptidase
B) glucosidase II
C) oligosaccharyltransferase
D) protein disulfide isomerase
E) phosphomannose isomerase
oligosaccharyltransferase
____ can bind and transport lipids through the cytosol from one membrane compartment to another.
A) Motor proteins
B) Lipid-transfer proteins
C) Glycosyltransferases
D) Flippases
E) Dolichol phosphate
Lipid-transfer proteins
Membrane protein topology is determined by ___ residues flanking the transmembrane segments, which tend to move towards and/or stay at the cytosolic side of the ER membrane.
A) positively charged
B) hydrophobic
C) glycosylated
D) asparagine
E) serine and threonine
positively charged
Genetic deficiency in the enzyme phosphomannose isomerase can be managed by taking supplements of _____.
A) dolichol phosphate
B) asparagine
C) N-acetylglucosamine
D) mannose
E) N-acetylglucosamine 1-phosphate
mannose
Misfolded proteins are destroyed in the _____.
A) RER
B) sarcoplasmic reticulum
C) ribosomes
D) proteasomes
E) SER
proteasomes
The cis Golgi network is thought to function primarily as a sorting station that distinguishes between proteins to be shipped back to the ER and those that are allowed to proceed to the _____.
A) medial cisternae of the Golgi
B) trans Golgi network
C) cis cisternae of the Golgi
D) trans cisternae of the Golgi
E) lysosomes
cis cisternae of the Golgi
The trans Golgi network is a sorting station where proteins are segregated into different types of vesicles heading to either the plasma membrane or to various intracellular destinations, such as the _____.
A) chloroplast
B) lysosomes
C) peroxisomes
D) mitochondria
E) endoplasmic reticulum
lysosomes
_____ vesicles move materials in the anterograde direction.
A) COPI and COPII coated
B) Clathrin-coated
C) COPII-coated
D) COPI-coated
COPII-coated
_____ move materials in either anterograde or retrograde direction depending on where the vesicles came from.
A) Clathrin-coated vesicles
B) COPI-coated vesicles
C) COPI and COPII coated vesicles
D) COPII-coated vesicles
Clathrin-coated vesicles
Proteins that normally reside in the ER contain retrieval signals that are recognized by the _____.
A) mannose 6-phosphate receptor
B) PTS receptor
C) cargo receptor
D) KDEL receptor
E) TOM complex
KDEL receptor
Production of clathrin coated vesicles at the TGN begins with the recruitment of ___ which sets the stage for the binding of other coat proteins.
A) Sar1
B) Sec24
C) Arf1
D) GGA adaptors
E) Rabs
Arf1
The ____ is thought to function primarily as a sorting station that distinguishes between proteins to be shipped back to the ER and those that are allowed to proceed to the next Golgi station.
A) cis Golgi network
B) cis and medial cisternae of the Golgi
C) endoplasmic reticulum
D) trans cisternae of the Golgi
E) trans Golgi network
cis Golgi network
In animal cells, sialic acid is added to the terminal end of the oligosaccharide chain of a glycoprotein when the glycoprotein reaches the _____.
A) trans cisternae of the Golgi
B) endoplasmic reticulum
C) cis and medial cisternae of the Golgi
D) cis Golgi network
E) trans Golgi network
trans cisternae of the Golgi
Certain integral membrane proteins of the ER are selectively captured by ____ because they contain “ER export” signals as part of their cytosolic tail.
A) Arf1
B) clathrin
C) GGA adaptor
D) Sar1
E) cargo receptors
cargo receptors
_____ move materials in a retrograde direction.
A) Clathrin-coated vesicles
B) COPI-coated vesicles
C) COPI and COPII coated vesicles
D) COPII-coated vesicles
COPI-coated vesicles
Lysosomal enzymes in the TGN are recognized and captured by the _____.
A) mannose 6-phosphate receptor
B) KDEL receptor
C) PTS receptor
D) TOM complex
E) cargo receptor
mannose 6-phosphate receptor
Proteins enter peroxisomes through the ____.
A) TIM complex
B) importomer
C) TOM complex
D) Toc complex
E) Tic complex
importomer
Mannose residues in the newly synthesized glycoprotein are removed when the glycoprotein reaches the _____.
A) endoplasmic reticulum
B) cis Golgi network
C) trans Golgi network
D) cis and medial cisternae
E) trans cisternae
cis and medial cisternae
The ____ is a sorting station where proteins are segregated into different types of vesicles heading to either the plasma membrane or to various intracellular destinations.
A) endoplasmic reticulum
B) cis and medial cisternae of the Golgi
C) trans cisternae of the Golgi
D) trans Golgi network
E) cis Golgi network
trans Golgi network
Unlike the N-linked oligosaccharides whos synthesis begins in the ___, those attached to proteins by O-linkages are assembled entirely in the ____.
A) ER, Golgi
B) ribosomes, nucleus
C) thylakoid membrane, stroma
D) inner mitochondiral membrane, mitochondrial matrix
E) plasma membrane, extracellular matrix
ER, Golgi
The vesicle coat contains ____ that bind the outer surface of the lipid bilayer and the cargo receptor.
A) adaptor proteins
B) motor proteins
C) integral proteins
D) G proteins
E) scaffolding proteins
adaptor proteins
The vesicle coat contains ____ that initiate vesicle formation and regulate the assembly and disassembly of the vesicle coat.
A) coatomer proteins
B) G proteins
C) integral proteins
D) motor proteins
E) adaptor proteins
G proteins
The initial contact between a transport vesicle and its target membrane is mediated by tethering proteins such as _____.
A) golgins
B) SNAREs
C) NSF
D) Rabs
E) mtHSP70
golgins
The regulated destruction of the cell’s own organelles is known as ____.
A) receptor-mediated endocytosis
B) autophagy
C) ER-associated degradation
D) regulated secretion
E) unfolded protein response
autophagy
When a mitochondrion is surrounded by a double membrane during autophagy, it produces a sequestering vesicle known as a/n ______, which fuses with a lysosome.
A) phagolysosome
B) autophagosome
C) phagosome
D) autolysosome
E) phagophore
autophagosome
Coated vesicles that form during endocytosis contain a layer of adaptors, such as _____.
A) Sar1
B) Arf1
C) clathrin
D) GGA
E) AP2
AP2
Phosphate groups can be added to the sugar ring of _____ to form phosphoinositides.
A) phosphatidylinositol
B) ADP
C) proteins
D) glucose
E) mannose
phosphatidylinositol
___ is a proteolytic enzyme that destroys LDL receptors.
A) Lovastatin
B) PCSK9
C) REGN727
D) AMG145
E) Lipitor
PCSK9
The ____ serves as a sorting station that directs different types of receptors and ligands along different pathways.
A) secretory pathway
B) endoplasmic reticulum
C) Golgi complex
D) early endosome
E) ribosome
early endosome
Lysosomal membranes contain highly glycosylated integral proteins whose carbohydrate chains shields the membrane from attack by _____.
A) acid hydrolases
B) free radicals
C) phagocytic cells
D) antibodies
E) potentially dangerous microorganisms
acid hydrolases
The cell internalizes cell-surface receptors and bound extracellular ligand through ____.
A) pinocytosis
B) exocytosis
C) clathrin-mediated endocytosis
D) phagocytosis
E) bulk-phase endocytosis
clathrin-mediated endocytosis
Recycling of membranes between the cell surface and interior compartments happens through ____.
A) exocytosis
B) pinocytosis
C) clathrin-mediated endocytosis
D) phagocytosis
E) receptor-mediated endocytosis
pinocytosis
Endocytosis of ____ leads typically to the delivery of the bound materials to the cell and the return of the receptor to the cell surface for additional rounds of uptake.
A) EGF receptors
B) SRP receptors
C) LDL receptors
D) MPR receptors
E) insulin receptors
LDL receptors
Endocytosis of ____ often leads to the destruction of the receptor which reduces the sensitivity of the cell to further stimulation.
A) LDL receptors
B) insulin receptors
C) SRP receptors
D) MPR receptors
E) transferrin
insulin receptors
The ____ is able to inhibit the fusion of its phagosome with a lysosome.
A) autophagosome
B) bacterium that causes meningitis
C) phagocytic cell
D) bacterium responsible for Q fever
E) agent responsible for tuberculosis
agent responsible for tuberculosis
The high internal proton concentration in the ____ is maintained by a V-type H+-ATPase.
A) intermembrane space
B) stomach
C) lysosomes
D) ER lumen
E) thylakoid lumen
lysosomes
The ____ contains active transporters that pump ions into the vacuole.
A) tonoplast
B) chloroplast
C) plasma membrane
D) mitochondrion
E) lysosome
tonoplast
Dynamin is a large GTP-binding protein that is required for the fission of the vesicle from the ______.
A) plasma membrane
B) tonoplast
C) lysosome
D) Golgi
E) ER membrane
plasma membrane
Dissociation of the clathrin coat from the vesicle requires the hydrolysis of ____.
A) Hsc70
B) auxilin
C) GTP
D) ATP
E) clathrin
ATP
The level of LDL in the blood has been related to the development of _____.
A) atherosclerosis
B) multivesicular bodies
C) lipofuscin granules
D) tuberculosis
E) meningitis
atherosclerosis
The ____ produces proteins that destroy the integrity of the lysosomal membrane.
A) bacterium responsible for Q fever
B) autophagosome
C) phagocytic cell
D) agent responsible for tuberculosis
E) bacterium that causes meningitis
bacterium that causes meningitis
Nine A tubules in the ____ are connected to a central hub with nine spokes called the cartwheel.
centrioles
The outer microtubules in a cilium are generated from the _____.
basal body
The number of protofilaments in the microtubule is dictated by the number of ___ around the ring.
gamma tubulins
Prior to mitosis in plants, cortical microtubules disappear except for some, which forms the ___ that encircles the cell.
preprophase band
Towards the end of mitosis in plants, the mitotic spindle disappears, and is replaced by a bundle of microtubules called the _____, which plays a role in cell wall formation.
phragmoplast
The ____ consists of peripheral doublet microtubules surrounding a central pair of single microtubules, forming what is called the 9+2 array.
axoneme
IFT trains carrying tubulin are transported to the tip of the cilium by ____.
kinesin-2
Nucleation of microtubules can take place in _____.
centrosomes
The flagellum of a sperm cell comes directly from the _____.
basal body
The ___ determines the polarity of the entire microtubule and also forms a cap at the latter’s minus end, preventing the gain and loss of tubulin subunits.
gamma tubulin ring complex
Microtubule stability is also regulated by posttranslational modifications such as the covalent attachment of ___.
glutamates
The nine-fold symmetry of the centriole results from the structure of the ____.
SAS-6 protein
Which of the following are responsible for the bending motion in cilia and flagella?
axonemal dyneins
In secondary cilia, basal bodies do not form from centriole duplication, but assemble in large amorphous structures called ____.
deuterosomes
____ is a drug that binds to tubulin subunits and blocks their use by the cell.
Colcemid
MTOCs control the number of protofilaments that make up the walls of ____.
microtubules
Differences in microtubule stability are determined by different microtubule interacting proteins such as ____, some of which regulate the rate of the microtubule’s growth and shrinkage or the frequency of interconversion between the two phases.
+TIPs
____ binds to the microtubule polymer and inhibits its disassembly.
Taxol
Which of the following have GTPase activity?
gamma tubulins (no)
alpha tubulins (no)
The doublets in the _____ are connected to one another by the nexin link.
central tubules
In intraflagellar transport, IFT particles are brought back to the cell body by ____.
cytoplasmic dyneins
____ are strong, flexible, ropelike fibers in the cell that provide mechanical strength to neurons and epithelial cells lining the body’s cavities.
Intermediate filaments
The ____ in a vertebrate embryo leave the developing nervous system and migrate across the width of the embryo to form pigment cells, teeth, and cartilage.
neural crest cells
Although actin filaments can generate forces on their own, most processes that involve actin require the activity of motor proteins, specifically _____.
myosin
Muscle fibers have multiple nuclei because each fiber came from the fusion of many _____.
myoblasts
The largest protein yet to be discovered in any organism is ____, which is a highly elastic protein that stretches like a molecular spring.
titin
The impulse generated in a skeletal muscle is propagated into the interior of the cell along membranous folds called ____.
transverse tubules
Arp2/3 is activated by binding to the side of an actin filament and to an activating protein such as ____.
WASP
Assembly and disassembly of intermediate filaments are controlled primarily by _____.
phosphorylation and dephosphorylation
_____ plays a key structural role in the alignment of the myofibrils of a muscle cell, the absence of which makes the cells extremely fragile.
Desmin
Myosin Va is required to transport pigment granules from the ____ into hair follicles.
pigment cells
A longitudinal section of a muscle fiber reveals a cable made up of thinner cylindrical strands called ___.
myofibrils
____ is an elongated molecule that blocks the myosin-binding sites on the actin molecules of thin filaments.
Tropomyosin
The inability of myosin cross-bridges to detach in the absence of ATP is the basis for ____.
rigor mortis
The ____ are nucleating proteins that generate unbranched filaments, such as those found in focal adhesions.
formins
Intermediate filaments are often connected to other cytoskeletal elements by cross-bridges made of _____.
plectin
The primary structural protein of epithelial cells is _____.
keratin
Plant cells rely primarily on ____ to serve as tracks for long distance transport of cytoplasmic vesicles and organelles
actin
Hair cells in the inner ear are named for the ___ on the apical surface of the cells.
stereocilia
At its outer edges, a sarcomere has a pair of lightly staining I bands, which are made up of ____.
actin
The point of contact of an axon terminal with a muscle fiber is known as the ______.
neuromuscular junction
____ are proteins that bind to actin-ATP monomers and prevent them from polymerizing.
Thymosins
The wall of a microtubule is composed of globular proteins arranged in longitudinal rows, termed ____.
protofilaments
Cellullose synthase is a a transmembrane protein whose cytoplasmic side is attached to _____ through a protein called Cellullose Synthase Interactive Protein 1.
cortical microtubules
A kinesin molecule binds to microtubules using its _____.
head
In an axon that stretches from the spinal cord to the tip of a finger, kinesins transport vesicles and other cargo to the ____.
tip of the finger
Cytoplasmic dynein is reponsible for _____.
outward movement of membranous organelles towards the plasma membrane (no)
separating the chromosomes during mitosis and meiosis (no)
The brains of people with Alzheimer’s disease contain tangled filaments made up of excessively phosphorylated ____ molecules.
tau
Kinesins and dyneins move along microtubules, whereas myosins move along ____.
microfilaments
A cytoplasmic dynein molecule binds to microtubules using its _____.
stalk
Structures and materials traveling from the cell body toward the terminals of a neuron are said to move in a/n ____ direction.
anterograde
The movement of kinesin molecules are described as being highly _____, which means they tend to move along the microtubules for considerable distances without falling off.
processive
Microtubules are long hollow unbranched tubes composed of subunits of the protein
tubulin
Treatment of cells with ___ promote microtubule disassembly.
colchicine
Differences in directional movement of kinesins have been traced to differences in their ___ regions.
neck
A kinesin molecule binds to vesicles and organelles using its _____.
tail
Cytoplasmic dyneins do not interact directly with membrane bounded cargo but require adaptors, such as _____.
dynactin
Which of the following is present in succinate dehydrogenase?
presequence
Which of the following consists of three polypeptide chains arranged in a triple helix and aligned in staggered rows?
collagen
Which of the following is a glycolipid?
phosphatidylinositol
Which of the following binds to RGD containing peptides?
Integrin
COPII coated vesicles are targeted to the ____.
Golgi
Which of the following is a membrane lipid?
cholesterol
N-Glycosylation of proteins occurs in the ____.
RER
Which of the following is made in free ribosomes?
keratin
Which of the following are cell adhesion molecules involved only in heterophilic interactions?
Selectins
Which of the following guides the migration of primordial germ cells?
Laminin
Which of the following is a membrane carbohydrate?
glycocalyx
Which of the following are cell adhesion molecules associated with focal adhesions?
Integrins
Dolichol phosphate is found in the _____.
Rough endoplasmic reticulum
Which of the following is present in cytochrome c?
presequence
Proteins are destroyed in the ____.
Proteosome
Which of the following transports solutes in either direction across the membrane depending on the concentration gradient of the solute to be transported?
Na+/glucose cotransporter (no)
Na+/K+ ATPase
Mannose 6-phosphate receptor is made in the ____.
RER
Which of the following transports solutes by passive diffusion?
K+ channel
Which of the following is present in acid hydrolases?
signal peptide
Which of the following are cell adhesion molecules associated with hemidesmosomes?
Cadherins (no)
Intermediate Filaments?
Signal recognition particle (SRP) is made in the ____.
Free ribosomes
Laminins are O-glycosylated in the _____.
Golgi apparatus
Glucosidase II occurs in the ____.
RER
Which of the following are cytoskeletal elements associated with desmosomes?
Intermediate Filaments
Glycosaminoglycans are made in the ____.
Golgi
Oligosaccharyltransferase is found in the ____.
RER
O-Glycosylation of proteins occurs in the ____.
RER (no)
Golgi?
Which of the following are cell adhesion molecules associated with adherens junctions?
Cadherins
Which of the following is involved in the recycling of membrane between the cell surface and interior compartments?
Pinocytosis
Protein disulfide isomerase is made in the ____.
RER
Which of the following are cell adhesion molecules involved in either homophilic or heterophilic interactions?
Immunoglobulins
Which of the following are cytoskeletal elements associated with hemidesmosomes?
Intermediate Filaments
Which of the following are cytoskeletal elements associated with adherens junctions?
Actin Filaments
Cadherins are made in the ____.
RER
Chaperones are found in the _____.
Rough endoplasmic reticulum
Which of the following is a lipid anchored protein?
signal recognition particle (no)
sar1
Which of the following is a membrane protein?
LDL receptor
Which of the following contains keratan sulfate and hyaluronic acid?
Collagen (no)
Proteoglycan
Which of the following is a peripheral membrane protein?
plastoquinone (no)
cytochrome c
N-glycosidic linkages are present in _____.
glycocalyx (no)
proteoglycans
Which of the following consists of two similar but not identical polypeptides joined by disulfide bridges?
Fibronectin
The core protein of proteoglycans is made in the ______.
RER
Laminins are made in the _____.
Centrosome
Rough endoplasmic reticulum
Which of the following is present in the EGF receptor?
signal peptide
Clathrin coated vesicles are targeted to the ____.
Lysosomes
Intermediate filaments are made in the _____.
Free ribosomes
Which of the following are cell adhesion molecules associated with desmosomes?
Cadherins
Hydrophobic alpha-helices are most likely found in _____.
cytochrome c oxidase
Which of the following are cell adhesion molecules involved only in homophilic interactions?
Cadherins
Which of the following is present in plastocyanin?
transit peptide
