front 1 A pharmacologist describes the cell membrane as allowing some solutes
through while restricting others. Which property best matches this
description? | back 1 C. Selectively permeable barrier |
front 2 A toxin selectively disrupts smooth endoplasmic reticulum function.
Which cellular process is most directly impaired? | back 2 B. Lipid synthesis |
front 3 A cell loses structural integrity after simultaneous disruption of
its primary cytoskeletal systems. Which set best lists those
systems? | back 3 D. Actin, intermediate, tubulin |
front 4 A pituitary signal enters the bloodstream to act at distant targets.
In that system, the chemical messenger is termed a: | back 4 B. Hormone |
front 5 A macrophage secretes a protein that coordinates local immune
activity. In that system, the messenger is termed a: | back 5 C. Cytokine |
front 6 Which trio matches the listed nonspecific messengers? | back 6 A. Retinoids, eicosanoids, growth factors |
front 7 A T cell requires direct membrane contact with an antigen-presenting
cell to receive an activating signal. Which signaling mode is
described? | back 7 D. Juxtacrine |
front 8 A wound-healing mediator diffuses a short distance to alter gene
expression in adjacent cells. Which signaling mode is
described? | back 8 A. Paracrine |
front 9 A review classifies receptors into two broad groups. Which pair
matches the listed receptor classes? | back 9 B. Plasma membrane, intracellular binding proteins |
front 10 A student lists subclasses of plasma membrane receptors. Which option
is NOT one of the listed plasma membrane subclasses? | back 10 C. Intracellular binding proteins |
front 11 A hormone receptor complex is found directly regulating transcription
of a specific gene. Which description best matches most intracellular
receptors? | back 11 A. Gene-specific transcription factors |
front 12 A signaling molecule binds an intracellular receptor that then
localizes to the nucleus. What does this receptor class bind
directly? | back 12 D. DNA |
front 13 A growth signal activates a receptor that increases its kinase
activity through a specific chemical modification. What activates
tyrosine kinases as listed? | back 13 B. Phosphorylation |
front 14 A pathway diagram notes that ligand binding triggers a shape change
in a signal transducer by binding to a specific domain. Which domain
is listed? | back 14 C. SH2 domain |
front 15 A question bank lists common second messengers. Which molecule is NOT
included in the provided list? | back 15 D. cGMP |
front 16 A microbiology lab optimizes culture conditions for Vibrio cholerae.
Which condition best supports growth as listed? | back 16 A. Alkaline conditions |
front 17 A traveler develops profuse watery diarrhea from Vibrio cholerae
infection. Activation of which epithelial channel is listed as the
mechanism? | back 17 B. CFTR channel |
front 18 A clinician wants an enzymatic uric acid level determination in a
patient with suspected gout. Which enzyme activity is observed as
listed? | back 18 C. Uricase |
front 19 A patient has recurrent gout. Based on the listed scheme, which
pairing correctly matches “treatment” vs “prevention”? | back 19 D. Colchicine / allopurinol |
front 20 During prolonged fasting, one tissue synthesizes ketone bodies while
another uses them. Which pairing matches the listed mitochondrial
enzyme distribution? | back 20 B. Liver synthesizes; muscle uses |
front 21 A lecturer emphasizes membrane asymmetry and asks where glycoproteins
and glycolipids are predominantly located. Which leaflet is correct as
listed? | back 21 A. Outer leaflet |
front 22 A pathology question describes the carbohydrate layer (glycocalyx) on
the outer cell surface. What is its listed function? | back 22 C. Cell recognition marker |
front 23 A membrane lipid is identified as the principal sphingolipid
component. Which lipid is correct as listed? | back 23 D. Sphingomyelin |
front 24 A drug flips membrane lipids and disrupts normal leaflet composition.
Which pair is listed as typical for the outer leaflet? | back 24 B. Phosphatidylcholine, sphingomyelin |
front 25 A genetics vignette references inner leaflet signaling scaffolds and
asks which set is typical for the inner leaflet as listed. | back 25 C. Phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine |
front 26 A physiology stem asks which lipid is specifically noted as
contributing to membrane potential due to its net negative charge.
Which lipid is correct as listed? | back 26 A. Phosphatidylserine |
front 27 Which outer-leaflet lipids are hydrolyzed by a key Clostridium
perfringens toxin? | back 27 C. Phosphatidylcholine and sphingomyelin |
front 28 In gas gangrene, toxin-driven membrane lysis most directly benefits
the bacteria by providing: | back 28 A. Nutrients for bacterial growth |
front 29 A lab increases membrane rigidity by altering lipid composition.
Which pair is listed as determining membrane fluidity? | back 29 D. Cholesterol and unsaturated fatty acids |
front 30 A patient with impaired CO₂ transport has a defective RBC “chloride
shift.” Which RBC membrane protein normally exchanges bicarbonate and
chloride? | back 30 B. Band 3 anion exchanger |
front 31 In systemic capillaries, CO₂ entry into RBCs drives the “chloride
shift.” Which direction best matches the listed exchange? | back 31 B. Cl− in, HCO3− out |
front 32 A hematology question asks which RBC membrane component provides an
external negative charge that repels other cells. | back 32 D. Glycophorin sialic acid coat |
front 33 In hereditary spherocytosis, a mutation disrupts linkage between Band
3 and the cytoskeleton. Which adaptor connects Band 3 to
spectrin? | back 33 C. Ankyrin adaptor protein |
front 34 A distinct RBC membrane defect disrupts the glycophorin-based
junctional complex. Glycophorin links to actin and spectrin
through: | back 34 B. Protein 4.1 |
front 35 Which prominent peripheral protein provides mechanical
support? | back 35 A. Spectrin peripheral scaffold |
front 36 A neurologic vignette references CJD/mad-cow and notes the culprit
prion protein is tethered to neuronal membranes by a: | back 36 D. GPI anchor |
front 37 A mutation broadly impairs lysosomal digestion. Which set matches the
listed lysosomal digestive enzymes? | back 37 B. Nucleases, phosphatases, glycosidases, esterases, proteases |
front 38 The lysosomal enzymes are best categorized as: | back 38 C. Hydrolases |
front 39 An experimental drug raises intralysosomal pH and causes substrate
buildup. These enzymes normally function in an: | back 39 A. Acidic lumen |
front 40 “Cystine proteases” in lysosomes are also called: | back 40 B. Cathepsins |
front 41 A biochem study finds peak lysosomal hydrolase activity at which
listed pH? | back 41 D. pH 5.5 |
front 42 A genetic defect prevents lysosomes from maintaining acidity. Which
listed pump maintains the acidic lumen? | back 42 C. V-ATPases proton pump |
front 43 "Vesicular ATPases” maintain intralysosomal pH. They are best
described as a(n): | back 43 A. Active proton pump |
front 44 A population genetics stem asks about heterozygote advantage in
cystic fibrosis. Heterozygotes are described as immune to: | back 44 D. Cholera |
front 45 Cholera toxin causes diarrheal fluid loss by making CFTR do which
listed behavior in intestines? | back 45 B. Stay open in intestines |
front 46 The CFTR change above most directly produces: | back 46 C. Dehydration from secretory diarrhea |
front 47 In this mechanism, intestinal secretion increases which listed ions
into the lumen? | back 47 D. Chloride and sodium |
front 48 The ion secretion above is followed by net loss of: | back 48 A. Water |
front 49 A lysosomal storage disease question asks what accumulates in
Tay-Sachs, per the provided pairing. | back 49 C. Ganglioside accumulation |
front 50 A second lysosomal storage disease asks what accumulates in Pompe,
per the provided pairing. | back 50 B. Glycogen accumulation |
front 51 What is involved in oxidative reactions using molecular
oxygen? | back 51 A. Peroxisome |
front 52 Another listed peroxisomal role is to: | back 52 B. Convert cholesterol to bile salts |
front 53 Peroxisomes synthesize ether lipids called: | back 53 C. Plasmalogens ether lipids |
front 54 Which statement about peroxisomes matches the provided
material? | back 54 A. Contain no DNA |
front 55 The largest subcellular organelle in animal cells is the: | back 55 D. Nucleus |
front 56 A cell with increased ribosome production shows a prominent nuclear
substructure. The nucleolus is the site of: | back 56 B. rRNA transcription and ribosome assembly |
front 57 The nucleus is separated by the nuclear envelope and communicates
with cytoplasm through: | back 57 C. Nuclear pores |
front 58 Electron microscopy shows the outer nuclear membrane blending
directly into a ribosome-studded cisternal network. That membrane is
continuous with: | back 58 A. Rough endoplasmic reticulum |
front 59 A transcription factor enters the nucleus normally but cannot leave,
causing nuclear accumulation. Which signal is most likely
defective? | back 59 B. Nuclear export signal |
front 60 A hepatocyte shows extensive ER tubules without surface ribosomes.
Which organelle is described? | back 60 C. Smooth ER |
front 61 After chronic exposure to a toxic solvent, hepatocytes upregulate a
smooth-ER enzyme class for xenobiotic metabolism. Which class is
it? | back 61 D. Cytochrome P450 enzymes |
front 62 A path slide shows glycogen concentrated in cytoplasmic regions rich
in which organelle? | back 62 B. Smooth ER |
front 63 A newly synthesized enzyme is destined for a membrane-bound organelle
(e.g., lysosome). Where is it most likely synthesized? | back 63 A. Rough ER ribosomes |
front 64 A secreted protein is translated on ER-bound ribosomes. What is the
next major trafficking station listed? | back 64 C. Golgi complex |
front 65 A peptide hormone is synthesized on RER and processed through Golgi.
Which listed fate is appropriate? | back 65 D. Secreted from the cell |
front 66 A lab assay detects N-linked glycosylation on a nascent polypeptide.
Where does this modification primarily occur? | back 66 A. Rough endoplasmic reticulum |
front 67 A cytosolic enzyme is translated on free ribosomes. Its
posttranslational modification status is most consistent with: | back 67 B. Seldom modified |
front 68 A child with neurodegeneration has a peroxisomal disorder where
membrane transport of fatty acids is reduced due to decreased
transporter content. Which defect best matches? | back 68 D. Peroxisomal fatty-acid transporter loss |
front 69 A neonate has hypotonia and multisystem disease from failure to
produce proteins required for peroxisome synthesis. Which disorder
matches? | back 69 C. Zellweger syndrome |
front 70 Which option correctly lists the three Golgi compartments
provided? | back 70 A. Cis, medial, trans |
front 71 On EM, the convex Golgi face oriented toward the nucleus is
the: | back 71 D. Cis Golgi network |
front 72 A vesicle budding from the Golgi face nearest the plasma membrane
most likely originates from the: | back 72 C. Trans Golgi network |
front 73 A motor protein moves vesicles and positions organelles along tracks
composed of: | back 73 A. Tubulin microtubules |
front 74 A migrating fibroblast requires cytoskeletal elements for movement.
Which pair is listed as involved? | back 74 D. Actin and tubulin |
front 75 A patient’s cells show reduced tensile strength due to defects in
fibrous cytoskeletal proteins. Which component is implicated? | back 75 B. Intermediate filaments |
front 76 The primary role of intermediate filaments in the cell is: | back 76 C. Structural support |
front 77 In the general signaling sequence, what is the first listed event
after a stimulus occurs? | back 77 A. Messenger secreted |
front 78 In the general signaling sequence, which listed step represents
termination? | back 78 B. Signal ceases |
front 79 The monomeric G-protein Arf belongs to which superfamily? | back 79 C. Ras superfamily |
front 80 Arf is also known as: | back 80 D. ADP-ribosylation factor |
front 81 In a cholera model, blocking Arf prevents entry of which toxin
component into cells? | back 81 A. Cholera A toxin |
front 82 Neurotransmitters are secreted from neurons in response to: | back 82 D. An action potential |
front 83 At a cholinergic synapse, what directly triggers acetylcholine
release into the cleft? | back 83 B. Ca2+ influx |
front 84 A protein found in the cytoplasm, peroxisomes, or nucleus is most
likely synthesized on: | back 84 C. Free ribosomes |
front 85 A secretory protein contains multiple disulfide bonds and a lipid
anchor addition consistent with the listed site of these
modifications. Where do they occur? | back 85 D. Rough ER |
front 86 A receptor translated on RER and sorted through Golgi ultimately
becomes part of the cell surface. Which listed fate matches? | back 86 A. Embedded in plasma membrane |
front 87 A protein fails to enter the nucleus and accumulates in cytosol
despite normal synthesis. Which signal most directly governs nuclear
entry? | back 87 C. Nuclear localization signal |
front 88 Steroid-producing cells show abundant smooth ER with P450 activity.
Which process is most directly supported? | back 88 B. Steroid hormone synthesis |
front 89 A boy develops progressive neurologic decline; testing reveals
reduced peroxisomal membrane fatty-acid transporter content. Which
disorder best matches? | back 89 D. Adrenoleukodystrophy |
front 90 In the general signaling sequence, what is the earliest event that
occurs after an initial stimulus? | back 90 C. Messenger secreted |
front 91 A locally acting mediator is released and then reaches adjacent cells
before binding its receptor. Which step best describes “reaches
adjacent cells”? | back 91 A. Messenger diffuses/transported |
front 92 A ligand has arrived at its target tissue but no downstream effect
occurs because the receptor is blocked. Which step is directly
prevented? | back 92 C. Receptor binds messenger |
front 93 A receptor binds its ligand normally, but a mutation prevents any
intracellular change despite binding. Which step is specifically
impaired? | back 93 B. Binding elicits response |
front 94 A signaling pathway remains “stuck on” due to impaired shutoff
mechanisms. Which step is failing? | back 94 D. Signal ceases, terminated |
front 95 A tyrosine kinase receptor example: | back 95 A. EGF receptor |
front 96 A receptor class that uses JAK-STAT. Which receptor type
fits? | back 96 B. Cytokine receptor |
front 97 A fibrotic signaling ligand activates a serine/threonine receptor
kinase pathway. Which ligand-receptor pair best fits? | back 97 C. TGF-β receptor |
front 98 Ligand binding to an RTK rapidly causes what key structural change
enabling kinase activation? | back 98 D. Receptor dimerization |
front 99 RTKs propagate signals by phosphorylating target proteins
predominantly on which residue? | back 99 B. Tyrosine |
front 100 In RTK signaling, which “second messenger” is listed as only rarely
involved? | back 100 A. Phosphatidylinositol |
front 101 In JAK-STAT signaling, activated JAK phosphorylates STAT, which then
enters the nucleus to act as a: | back 101 D. Gene transcription factor |
front 102 TGF-β signaling activates which nuclear-directed mediators to alter
gene expression? | back 102 C. SMAD proteins |
front 103 In the RTK → Ras pathway, what immediately follows “binding and
dimerization”? | back 103 B. Autophosphorylation |
front 104 A mutation prevents GDP→GTP exchange on Ras after RTK activation.
Which protein normally performs that exchange? | back 104 D. SOS (GEF) |
front 105 A biopsy shows constitutively “on” Ras driving proliferation. Which
nucleotide state defines activated Ras? | back 105 C. Ras–GTP bound |
front 106 A targeted therapy stabilizes inactive Ras. Which nucleotide state
defines deactivated Ras? | back 106 A. Ras–GDP bound |
front 107 A phosphotyrosine-binding adaptor is required to recruit SOS in RTK
signaling. Grb2 is best described as: | back 107 B. SH domain-containing protein |
front 108 In RTK signaling, Grb2 docks to the activated receptor using which
domain interaction? | back 108 D. SH2 binds phosphotyrosine |
front 109 After Grb2 binds the RTK, SOS is recruited by binding which Grb2
domain? | back 109 C. SH3 domain |
front 110 Once Ras is GTP-bound, it most directly promotes binding of which
target enzyme? | back 110 A. Raf |
front 111 In the RTK cascade, Raf is best classified as: | back 111 B. MAPKKK |
front 112 Raf’s intrinsic enzymatic activity is best described as: | back 112 D. Serine protein kinase |
front 113 A lipid signaling module (PIP2/PIP3) can be generated downstream of
which receptor families? | back 113 B. Tyrosine and heptahelical |
front 114 PIP2 cleavage into IP3 and DAG is catalyzed by which enzyme
class? | back 114 A. Phospholipase C |
front 115 In growth-factor RTK signaling, which PLC isozyme is activated to
cleave PIP2? | back 115 D. PLCγ |
front 116 In heptahelical GPCR signaling, which PLC isozyme is activated by
Gq/11? | back 116 B. PLCβ |
front 117 PIP3 forms membrane docking sites for proteins containing which
motif? | back 117 C. PH domain |
front 118 A tumor suppressor is lost, causing persistent PIP3 signaling because
PIP3 is not converted back to PIP2. What accumulates? | back 118 A. PIP3 |
front 119 Where is phosphatidylinositol predominantly located in the plasma
membrane? | back 119 B. Inner leaflet |
front 120 Phosphatidylinositol becomes PIP2 by phosphorylation at which
inositol carbons? | back 120 D. 4′ and 5′ |
front 121 Which enzyme adds a phosphate at the 3′ carbon to convert PIP2 to
PIP3? | back 121 A. PI 3-kinase |
front 122 PI 3-kinase activation in RTK signaling depends on binding a specific
phosphotyrosine site using which feature? | back 122 C. SH2 domain binding |
front 123 In the RTK cascade, activated Raf most directly triggers which
downstream program? | back 123 B. MAP kinase pathway |
front 124 In RTK → Ras signaling, which adaptor binds the receptor and recruits
SOS? | back 124 D. Grb2 |
front 125 TGF-β signaling brings together type 1 and type 2 receptors to
activate what enzymatic activity? | back 125 C. Serine-threonine kinase activity |
front 126 Which phosphoinositide is cleaved to generate DAG and IP3? | back 126 A. PIP2 |
front 127 The insulin receptor belongs to which receptor family? A. Serine-threonine kinase receptors | back 127 C. Tyrosine kinase receptors |
front 128 The insulin receptor is synthesized as a preformed complex. Which
subunit arrangement is correct? | back 128 A. α2β2 preformed heterotetramer |
front 129 A mutation prevents insulin receptor autophosphorylation despite
normal insulin binding. Which receptor component normally
autophosphorylates? | back 129 D. Cytosolic β subunits |
front 130 Immediately after insulin receptor autophosphorylation, which
substrate is recruited and phosphorylated? | back 130 B. IRS |
front 131 A patient’s insulin resistance is traced to impaired PI3K signaling.
Which insulin receptor branch is most tied to glucose
metabolism? | back 131 A. PI3K → Akt pathway |
front 132 In the insulin Akt pathway, which lipid conversion is catalyzed
downstream of IRS? | back 132 C. PIP2 to PIP3 |
front 133 PIP3 generation recruits two proteins to the plasma membrane before
Akt activation. Which pair is correct? | back 133 B. PDK1 and Akt |
front 134 At the membrane, which event directly activates Akt (PKB) in insulin
signaling? | back 134 D. PDK1 phosphorylates Akt |
front 135 A growth phenotype is driven by insulin receptor signaling through
Ras and MAP kinase. Which docking protein most directly links IRS to
Ras activation? | back 135 B. Grb2 |
front 136 Another name for heptahelical receptors is: | back 136 A. G-protein coupled receptors |
front 137 The “seven-transmembrane” name for GPCRs refers to seven
membrane-spanning: | back 137 C. α-helices |
front 138 GPCR signaling commonly uses which second messengers? | back 138 D. cAMP or IP3 |
front 139 When a G-protein α subunit is GDP-bound, it typically: | back 139 A. remains associated with βγ |
front 140 When a G-protein α subunit becomes GTP-bound, it typically: | back 140 C. dissociates from βγ |
front 141 Which Gα subtype stimulates adenylyl cyclase? | back 141 C. Gαs |
front 142 Which Gα subtype inhibits adenylyl cyclase? | back 142 A. Gαi |
front 143 Which Gα subtype activates phospholipase Cβ? | back 143 B. Gαq/11 |
front 144 Which Gα subtype activates cGMP phosphodiesterase? | back 144 D. GαT |
front 145 Platelet shape change is driven by Rho-mediated cytoskeletal
remodeling downstream of a GPCR. Which Gα subtype best fits? | back 145 C. Gα12/13 |
front 146 cAMP phosphodiesterases hydrolyze cAMP to: | back 146 A. 5′-AMP |
front 147 Insulin lowers cellular cAMP levels primarily by: | back 147 C. activating phosphodiesterase |
front 148 cAMP serves as an allosteric activator of: | back 148 D. Protein kinase A |
front 149 CFTR opening is promoted when it is phosphorylated by: | back 149 A. PKA |
front 150 After IRS phosphorylation, which protein binds a specific
phosphotyrosine site to initiate the Akt pathway? | back 150 C. Adenylyl cyclase |
front 151 In insulin signaling, Akt is also known as: | back 151 C. PKB |
front 152 A hepatocyte is exposed to glucagon, raising cAMP and activating PKA.
Which nuclear protein is phosphorylated by PKA catalytic
subunits? | back 152 C. CREB |
front 153 CREB primarily functions as a: | back 153 A. Gene transcription factor |
front 154 A bronchial smooth muscle GPCR activates phospholipase Cβ. Which Gα
subunit must bind PLCβ? | back 154 D. Gαq |
front 155 PLCβ hydrolyzes which membrane lipid to generate DAG and IP3? | back 155 B. PIP2 |
front 156 In this pathway, IP3 most directly stimulates release of: | back 156 A. Ca2+ |
front 157 In the same cascade, DAG most directly activates: | back 157 C. Ca binding and PKC |
front 158 A developmental biologist studies a contact-dependent pathway
classically used as the example of juxtacrine signaling. Which pathway
is it? | back 158 B. Notch signaling |
front 159 Which ligands bind the Notch receptor? | back 159 D. Delta and Jagged |
front 160 In Notch signaling, ligand binding triggers an extracellular cleavage
removing most of Notch’s ectodomain. Which protease family mediates
this step? | back 160 A. ADAM proteases |
front 161 After ADAM cleavage, which enzyme cleaves the remaining Notch segment
to release NICD? | back 161 C. γ-secretase |
front 162 NICD (or notch intracellular domain) ultimately activates which
transcription factor to initiate new transcription? | back 162 B. CSL |
front 163 Notch-driven CSL activation is most associated with: | back 163 D. Neurogenesis and embryonic development |
front 164 Serpentine (GPCR) receptors can be desensitized by which set? | back 164 A. Phosphorylation, internalization, degradation |
front 165 G-proteins terminate their own signals primarily by: | back 165 C. Hydrolyzing GTP |
front 166 GAPS most directly act by: | back 166 B. Accelerating GTP hydrolysis |
front 167 A patient with heavy alcohol use develops hepatic steatosis. A toxic
acetaldehyde effect is inhibition of: | back 167 D. Tubulin polymerization |
front 168 This acetaldehyde effect decreases hepatic production of: | back 168 A. VLDLs |
front 169 The hepatic consequence most directly described is: | back 169 C. Fatty liver disease |
front 170 In neutrophils, urate promotes pain in gout by driving conversion of
arachidonic acid into: | back 170 B. Leukotriene B4 |
front 171 Cholera toxin A causes secretory diarrhea by ADP-ribosylating which
G-protein subunit? | back 171 A. Gαs |
front 172 In intestinal epithelia, phosphorylation of CFTR: | back 172 B. Opens the channel |
front 173 CFTR is a member of which transport superfamily? | back 173 C. ABC |
front 174 Which statement best matches guanylyl cyclase signaling? | back 174 A. Cytoplasmic, no G-protein needed |
front 175 Elevated cGMP most directly activates: | back 175 D. Protein kinase G |
front 176 A patient with exertional angina is treated with a drug that
decomposes to NO and activates guanylyl cyclase. Which drug
fits? | back 176 B. Glycerol trinitrate |
front 177 A decompensated heart failure patient receives a β-natriuretic
peptide ligand that activates a guanylyl cyclase receptor. Which drug
fits? | back 177 C. Nesiritide |
front 178 A patient with erectile dysfunction is prescribed a drug that
increases cGMP by blocking its breakdown. Which mechanism
fits? | back 178 D. Inhibits cGMP phosphodiesterase |