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