CAPS 306 Final MCQ Flashcards

Which of the following best describes a first messenger:
a) ligand
b) cell surface receptor
c) intracellular receptor
d) intracellular signaling molecule
e) G-protein

Which of the following binds to a cell surface receptor:
a) insulin
b) estrogen
c) testosterone
d) all of the above
e) none of the above

Which of the following is a means to extinguish cell surface receptor-mediated signaling:
a) receptor activation
b) receptor sequestration
c) receptor trafficking to the cell surface
d) all of the above
e) none of the above

Serotonin release by a pre-synaptic nerve into the synaptic extracellular space that is then received by
a nearby post-synaptic nerve is known as:
a) endocrine signaling
b) paracrine signaling
c) autocrine signaling
d) all of the above
e) none of the above

Which of the following have enzymatic activity coded in their protein sequence:
a) G protein-coupled receptors
b) receptors with intrinsic enzyme activity
c) receptors with associated cytoplasmic enzymes
d) all of the above
e) none of the above

Which of the following is the source of the phosphate that is added to a protein by a kinase:
a) ATP
b) ADP
c) cAMP
c) GTP
d) GDP

Which of the following is NOT a characteristic of a signal transduction pathway that is initiated by a water soluble ligand:
a) causes changes in gene expression
b) has a distal signaling component
c) has a cytoplasmic component
d) has a proximal component
e) is initiated by the activation of an intracellular receptor

Fill in the blank: Signaling pathways that induce changes in __________ have a ___________ response, often taking hours.
a) gene expression, fast
b) gene expression, slow
c) protein function, fast
d) protein function, slow
e) none of the above

Which of the following is a component of the proximal signaling machinery initiated by G-protein- coupled receptor (GPCR) activation that leads to cAMP production?
a) G protein complex
b) adenyl cyclase
c) ATP
d) all of the above
e) none of the above

Which of the following are part of the cytoplasmic signaling machinery that directly leads to MAP kinase (MAPK) activation after ligand binding to a receptor tyrosine kinase (RTK)?
a) JAK kinases
b) SMADs
c) STATs
d) all of the above
e) none of the above

In the cytokine signaling pathway, which of the following directly bind to DNA and alter gene
expression:
a) JAK kinases
b) SMADs
c) STATs
d) all of the above
e) none of the above

Wnt binding to the Frizzled receptor initiates a signaling pathway that:
a) increases transcription of the ß-catenin gene
b) decreases transcription of the ß-catenin gene
c) increases proteosomal degradation of the ß-catenin protein
d) decreases proteosomal degradation of the ß-catenin protein
e) prevents ß-catenin from entering the nucleus

Which of the following are ligands that belong to the TGF-β family of receptors:
a) Activin
b) Notch
c) Bone Morphogenic Protein (BMP)
d) both a) and c)
e) all the above

Which of the following is NOT a component of the mechanical signaling pathway:
a) ECM ligands
b) integrins
c) scaffolding proteins
d) f-actin filaments
e) microtubules

Which of these ligands requires a carrier protein to travel through the blood during endocrine signaling?
a) Wnt
b) Delta
c) Insulin
d) Glucocorticoid
e) Serotonin

A ligand that is secreted by cells in the pancreas that binds to receptors present on the surface of the hepatocytes in the liver is an example of:
a) endocrine signaling
b) paracrine signaling
c) autocrine signaling
d) all of the above
e) none of the above

Which of the following bind ATP on their intracellular domain when they are activated:
a) ion channel-coupled receptors
b) G protein-coupled receptors (GPCR's)
c) receptor tyrosine kinases
d) all of the above
e) none of the above

G proteins are activated by:
a) GDP binding
b) GDP hydrolysis
c) GTP release
d) all of the above
e) none of the above

In the cytokine signaling pathway, which of the following bind DNA:
a) Smads
b) ß-catenin
c) JAK kinases
d) all of the above
e) none of the above

Which of the following are ligands that bind to integrins to initiate mechanical signaling:
a) extracellular matrix molecules
b) myosin motors
c) actin filaments
d) all of the above
e) none of the above

What does the enzymatic action of PI3-kinase create from PIP2:
a) phosphatidylinositol 3,4,5 trisphosphate (PIP3)
b) inositol (1,4,5) trisphosphate (IP3)
c) diacylglycerol (DAG)
d) all of the above
e) none of the above

Which of the following binds to protein kinase C (PKC):
a) phosphatidylinositol 3,4,5 trisphosphate (PIP3)
b) inositol (1,4,5) trisphosphate (IP3)
c) diacylglycerol
d) all of the above
e) none of the above

Which of the following can be activated by signal transduction pathways initiated by a single receptor tyrosine kinase:
a) Akt kinase
b) MAP kinase
c) calcium/calmodulin-dependent kinase (CaM-kinase)
d) all of the above
e) none of the above

Which of the following contribute to the recruitment of the Akt kinase and PDK1 to the plasma
membrane:
a) proline rich domains
b) SH2 domains
c) SH3 domains
d) all of the above
e) none of the above

Which of the following is phosphorylated by active G1-CDK to initiate the removal of the G1 to S restriction point:
a) MYC
b) E2F
c) G1/S cyclin
d) all of the above
e) none of the above

DNA damage causes which of the following:
a) phosphorylation of the p53 protein
b) expression of the p21CIP protein
c) inhibition cyclin/CDK activity
d) all of the above
e) none of the above

Ubiquinated cyclins are degraded by the proteolytic activity of:
a) initiator caspases
b) executioner caspases
c) the proteosome
d) all of the above
e) none of the above

In the cell survival signaling pathway initiated by the activation of a receptor tyrosine kinase (RTK),
which of the following would be considered a tumour suppressor:
a) PI3 kinase
b) AKT kinase
c) PTEN phosphatase
d) all of the above
e) none of the above

Regarding an oncogene, which of the following is correct:
a) formed by a dominant activating mutation
b) requires mutation of only one of the gene's alleles
c) constitutively turns on proliferative and/or survival signaling pathways
d) all of the above
e) none of the above

The 9:22 chromosomal translocation that drives proliferation in chronic myelogenous leukemia results in:
a) increased expression of SCF by stromal cells in the hematopoietic stem cell niche
b) increased activation of the Kit receptor tyrosine kinase present on hematopoietic stem cells
c) increased activity of the Abl tyrosine kinase in myeloid progenitor cells
d) all of the above
e) none of the above

Which of the following could contribute to the loss of tumor suppressor gene function:
a) amplification of the gene
b) a point mutation in the coding sequence of the gene
c) a mutation in the regulatory portion of the gene that increases its expression
d) all of above
e) none of the above

Which of the following is required to drive the abnormal proliferation in colonic stem cells that have lost the adenomatous polyposis coli (APC) tumor suppressor gene:
a) Wnt ligand
b) Frizzled receptor
c) ß-catenin
d) all of the above
e) none of the above

Which of the following is stimulated by increases in cytoplasmic calcium:
a) protein kinase C (PKC)
b) nitric oxide synthase
c) calmodulin
d) all of the above
e) none of the above

Which of the following makes it possible for multiple signaling proteins to bind to the same activated receptor tyrosine kinase dimer:
a) PH domains
b) SH2 domains
c) proline rich domains
d) all of the above
e) none of the above

During the cell cycle, levels of all cyclins are very low in:
a) G0 phase
b) S phase
c) G2 phase
d) all of the above
e) none of the above

DNA damage prevents cells from moving through or entering:
a) G1 phase
b) S phase
c) M phase
d) all of the above
e) none of the above

Which of the following inhibits transcription of the MYC gene:
a) Wnt signaling
b) receptor tyrosine kinase (RTK) signaling
c) transforming growth factor beta (TGFß) signaling
d) all of the above
e) none of the above

What protein cleaves 'Inhibitor of Caspase-Activated DNase' (iCAD) as a result of apoptotic signaling?
a) initiator caspases
b) executioner caspases
c) cytocrome c
d) all of the above
e) none of the above

Fill in the blank: Oncogenes are generated by __________, _________ mutations in one allele of the gene concerned:
a) recessive, gain of function
b) recessive, loss of function
c) dominant, loss of function
d) all of the above
e) none of the above

Fill in the blank: Tumour suppressors are lost when __________, _________ mutations occur in both alleles of the gene concerned:
a) recessive, gain of function
b) recessive, loss of function
c) dominant, loss of function
d) all of the above
e) none of the above

What does a loss of adenomatous poliposis coli (APC) cause, even in the absence of the Wnt ligand:
a) increases β-catenin binding to the TCF complex, causing an increase in proliferation
b) decreases β-catenin binding to the TCF complex, causing a decrease in proliferation
c) decreases β-catenin binding to the TCF complex, causing an increase in proliferation
d) all of the above
e) none of the above

Regarding Gleevec, which of the following is correct:
a) competes with ATP binding to Bcr/Abl
b) inhibits the kinase activity of Bcr/Abl
c) prevents stem cell factor - independent proliferation of common myeloid progenitor cells
d) all of the above
e) none of the above

When inappropriate signaling pathways initiate an epithelial- mesenchymal transition (EMT) in carcinoma cells, how is E-cadherin expression repressed:
a) transcriptionally
b) post-transcriptionally
c) translationally
d) all of the above
e) none of the above

After the first cell division of the zygote, the cells are called:
a) blastoballs
b) morumeres
c) blastomeres
d) trophomeres

Primary yolk sac (Heuser's membrane) appears with the:

a) second wave of hypoblast migration
b) epiblast ingression
c) first wave of hypoblast migration
d) primitive streak formation

The approximate window for notochord formation is days:

a) 10-12
b) 13-15
c) 16-22
d) 24-28

During gastrulation, epiblast ingression first produces:

a) mesoderm
b) ectoderm
c) definitive endoderm
d) extraembryonic mesoderm

Loss of Snail OR Slug in the primitive streak would most directly cause:
a) Excess E-cadherin and failure of EMT/ingression
b) Increased E-cadherin and enhanced migration
c) Loss of FGF signaling but normal EMT
d) Normal EMT with reduced notochord

Which pairing of timepoint and event is correct?
a) Day 14–15: definitive endoderm displaces hypoblast
b) Day 16: hatching from zona pellucida
c) Day 7–10: notochordal plate infolding
d) Day 21: morula formation

Pathway linking signals to EMT at the primitive streak:
a) Nodal → Oct4 → ↑E-cadherin → EMT
b) Nodal → Snail → ↓E-cadherin → EMT
c) Hedgehog → Sox2 → EMT
d) FGF → Sox2 → MET→ ↓E-cadherin → EMT

Which complex links regulatory TFs at enhancers to the basal transcription machinery at promoters?
a) SWI/SNF
b) PRC2
c) Mediator
d) COMPASS (MLL3/4)

What do p300/CBP primarily do at enhancers?
a) Add H3K27me3
b) Deacetylate histones
c) Add H3K27ac
d) Methylate DNA

PRC2 (with EZH2) is best described as a writer that adds which mark and effect?
a) H3K27ac—activation
b)H3K27me3—repression
c) H3K4me1—priming
d) H3K9ac—repression

Mis-targeting PRC2 to an active enhancer would most likely cause:
a) Gain of H3K27ac and more transcription
b) Loss of H3K27ac, gain of H3K27me3, reduced accessibility/transcription
c) Gain of H3K4me1 and stable priming without expression change
d) Nucleosome eviction and promoter melting

At the eight-cell stage, compaction most directly leads to which outcome?
a) Polarized outer cells forming trophoblast and inner cells forming embryoblast.
b) Uniform blastomeres maintaining totipotency with minimal polarity or adhesion changes.
c) Immediate cavitation, creating the blastocoel throughout the interior cell mass.
d) Epithelial-to-mesenchymal transition that initiates widespread mesodermal migration

Which feature best characterizes the syncytiotrophoblast during implantation?
a) Tight junction sealing between cells that prevents maternal immune cell entry into uterus.
b) It surrounds the embryoblast and starts to form the amnionic cavity
c) Endometrial invasion and hCG secretion establishing maternal blood contact.
d) It forms a protective layer between the embryo and cytotrophoblast cells

Which pairing correctly describes the immediate derivatives of the bilaminar embryo?
a) Epiblast makes yolk sac lining; hypoblast generates amniotic ectoderm and fluid.
b) Epiblast generates cytotrophoblast; hypoblast generates syncytiotrophoblast masses.
c) Epiblast makes embryo and amnionic cavity; hypoblast contributes to yolk sac lining.
d) Epiblast establishes chorionic villi; hypoblast establishes prechordal mesoderm.

Which sequence best matches the timing of early week-3 morphogenesis?
a) Notochord completes by day 12, while the primitive streak first appears by day 21.
b) Primitive streak regresses by day 10, while the secondary yolk sac appears at day 28.
c) Trilaminar disc of the three germ layers forms by day 17, while the notochordal process extends during days 16–22.
d) Somites form before the streak, while implantation only finishes after day 30.

Which chromatin signature best fits a primed but inactive developmental enhancer?
a) No histone marks with persistent promoter-proximal paused RNA polymerase.
b) High H3K27ac plus recruited Mediator and robust Pol II loading.
c) Dominant H3K27me3 plus PRC1 compaction and DNA methylation.
d) H3K4me1 present with no H3K27ac present.

In a model organism, an enhancer drives broad reporter expression, but adding a silencer yields stripes. Why?
a) Repressor inputs eliminate enhancer output where the repressor TF is present.
b) Mediator replaces RNA polymerase to reduce general transcription below detection.
c) PRC2 turns the enhancer into a promoter that transcribes the reporter alone.
d) Notch oscillations move the enhancer randomly between tissues over time.

Why does enhancer modularity aid precise spatial–temporal control during development?
a) One enhancer can splice transcripts to make multiple proteins in each tissue
b) Single enhancers enforce exclusivity by closing all other enhancers at a locus
c) Enhancers are restricted to 5′ promoters, so timing derives from promoter choice
d) Distinct enhancers can drive expression in different tissues or stages independently

Which alteration would most likely block induction of the forebrain neural plate?
a) Gbx2 knockout restricted to the posterior hindbrain territory.
b) Transient Noggin overexpression that reduces BMP signaling.
c) Localized overexpression of Wnt antagonists.
d) Excessive activation of Wnt signaling.

Which statement captures Hox gene co-linearity relevant to A–P patterning?
a) Chromosomal order parallels anterior-posterior expression boundaries along the embryo.
b) Expression strength, not position, determines anterior versus posterior identity.
c) Only forebrain relies on Hox; hindbrain excludes them during segmentation.
d) Hox expresses randomly and is refined later by cell rearrangements.

How do retinoic acid (RA) and FGF gradients contribute to A–P neural patterning?
a) Both act anteriorly to expand telencephalic identity across the midbrain region
b) RA is present in anterior Hox domains while FGF is present in more posterior identities
c) RA sets dorsal domains while FGF sets ventral domains by Notch activation alone
d) Both suppress Hox genes so Otx2 fills the entire hindbrain and spinal cord

In the spinal neural tube, which pairing matches a dorsal and ventral signal?
a) BMPs from roof plate and Shh from floor plate and notochord.
b) Wnts from floor plate and RA from roof plate and notochord.
c) FGFs from roof plate and BMPs from floor plate and notochord.
d) Shh from roof plate and BMPs from floor plate and notochord

A Numb hypomorph would most likely lead to what?
a) Widespread Notch ON, less proneural activity, and fewer neurons.
b) Widespread Notch OFF, more proneural activity, and more neurons.
c) Spreading of Par6 across the whole neuroblast membrane and block of asymmetric division
d) An anterior shift of the MHB toward the forebrain.