Question 1

Transcriptional activation downstream of the MAPK pathway involves:

Accepted Answer

A) MEK. 
B) CREB phosphorylation. 
C) binding of transcription factors to the SRE of c-Fos. 
D) recruitment of Raf's N-terminal regulatory domain. 
E) Ras activation upon Sos binding. 
A) MEK. 
B) CREB phosphorylation. 
C) binding of transcription factors to the SRE of c-Fos. 
D) recruitment of Raf's N-terminal regulatory domain. 
E) Ras activation upon Sos binding.

Question 2

What feature distinguishes the ligand Delta from other ligands such as EGF,TGFα,and erythropoietin that bind transmembrane receptors?

Accepted Answer

The other ligands are diffusible molecul

Question 3

Many kinases,including MAP kinase,protein kinase B,receptor tyrosine kinases,and JAKs,possess activation lips.What is an activation lip? What modification of the activation lip is required for activation of these kinases?

Accepted Answer

The activation lip is a region

Question 4

The order of events in a signaling pathway can be determined by the analysis of mutants.Cells that express a mutant defective Raf protein cannot be stimulated to proliferate uncontrollably by constitutively active Rasᴰ (dominant active).This indicates:

Accepted Answer

A) quiescent cells can be induced to proliferate in the absence of growth factors if they contain a constitutively inactive mutant Raf protein. 
B) Raf is upstream of Ras in the signaling pathway. 
C) Ras is upstream of Raf in the signaling pathway. 
D) Ras mutants are recessive to Raf mutants. 
A) quiescent cells can be induced to proliferate in the absence of growth factors if they contain a constitutively inactive mutant Raf protein. 
B) Raf is upstream of Ras in the signaling pathway. 
C) Ras is upstream of Raf in the signaling pathway. 
D) Ras mutants are recessive to Raf mutants.

Question 5

Which of the following receptors binds TGFβ?

Accepted Answer

A) type I 
B) type II 
C) type III 
D) types I and II 
E) types II and III 
A) type I 
B) type II 
C) type III 
D) types I and II 
E) types II and III

Question 6

Before ligand binding,receptor tyrosine kinases:

Accepted Answer

A) contain binding sites for SH2-domain containing proteins. 
B) contain activation lip tyrosines within the kinase active site. 
C) bind to GRB2 within the cytosolic domains. 
D) have excellent tyrosine kinase activity. 
A) contain binding sites for SH2-domain containing proteins. 
B) contain activation lip tyrosines within the kinase active site. 
C) bind to GRB2 within the cytosolic domains. 
D) have excellent tyrosine kinase activity.

Question 7

TGF- β normally promotes:

Accepted Answer

A) cell division. 
B) cell motility. 
C) tissue organization. 
D) all of the above 
A) cell division. 
B) cell motility. 
C) tissue organization. 
D) all of the above

Question 8

In which of the following double-mutant flies will R7 photoreceptors develop normally?

Accepted Answer

A) constitutively active Raf and inactive MAPK 
B) constitutively active MAPK and inactive Ras 
C) constitutively active Ras and inactive Raf 
D) all of the above 
E) none of the above 
A) constitutively active Raf and inactive MAPK 
B) constitutively active MAPK and inactive Ras 
C) constitutively active Ras and inactive Raf 
D) all of the above 
E) none of the above

Question 9

Ski and SnoN were originally identified as oncoproteins.Explain how constitutive expression of these proteins promotes cancer.

Accepted Answer

Ski and SnoN both inhibit TGFβ signaling

Question 10

Which of the following is a protein kinase?

Accepted Answer

A) EGF receptor 
B) erythropoietin receptor 
C) STAT5 
D) EGF receptor and erythropoietin receptor 
E) all of the above 
A) EGF receptor 
B) erythropoietin receptor 
C) STAT5 
D) EGF receptor and erythropoietin receptor 
E) all of the above

Question 11

All genes regulated by PKA contain a cis-acting DNA sequence that binds to the phosphorylated form of a transcription factor called:

Accepted Answer

A) β-catenin. 
B) CREB. 
C) c-Jun. 
D) TCF. 
A) β-catenin. 
B) CREB. 
C) c-Jun. 
D) TCF.

Question 12

Which of the following explains why Ras is activated quickly by RTKs?

Accepted Answer

A) RTKs phosphorylate Ras. 
B) Ras changes conformation upon ligand binding to prepare for activation. 
C) Ras binds phosphotyrosine residues on RTKs. 
D) Ras is maintained at the plasma membrane through a lipid-mediated attachment. 
A) RTKs phosphorylate Ras. 
B) Ras changes conformation upon ligand binding to prepare for activation. 
C) Ras binds phosphotyrosine residues on RTKs. 
D) Ras is maintained at the plasma membrane through a lipid-mediated attachment.

Question 13

How does activation of protein kinase B promote cell survival?

Accepted Answer

Protein kinase B phosphorylates and inhi

Question 14

Which of the following contain(s)an SH2 domain?

Accepted Answer

A) SHP1 
B) SOCS 
C) STAT5 
D) all of the above 
E) none of the above 
A) SHP1 
B) SOCS 
C) STAT5 
D) all of the above 
E) none of the above

Question 15

An SH2-containing protein contains a mutation that changes its binding pocket such that tyrosine and phosphotyrosine bind with equal affinity.As a result,MEK activity:

Accepted Answer

A) decreases due to changes in Raf activation. 
B) decreases due to allosteric inhibition of SH2-domain binding. 
C) increases with ligand binding-induced dimerization. 
D) does not change with receptor dimerization and transautophosphorylation. 
A) decreases due to changes in Raf activation. 
B) decreases due to allosteric inhibition of SH2-domain binding. 
C) increases with ligand binding-induced dimerization. 
D) does not change with receptor dimerization and transautophosphorylation.

Question 16

Describe the experimental approach used to determine the order of events in a signaling pathway.

Accepted Answer

The order of events in a signaling pathw

Question 17

Which of the following signaling pathways can be activated by cytokines?

Accepted Answer

A) JAK/STAT 
B) PI-3 kinase 
C) Ras/MAP kinase 
D) JAK/STAT and PI-3 kinase 
E) all of the above 
A) JAK/STAT 
B) PI-3 kinase 
C) Ras/MAP kinase 
D) JAK/STAT and PI-3 kinase 
E) all of the above

Question 18

How can multiple MAP kinase pathways be segregated when they share a common component?

Accepted Answer

Despite different MAP kinase pathways sh

Question 19

The EGF receptor is a(n):

Accepted Answer

A) adapter protein. 
B) guanine nucleotide exchange protein. 
C) kinase. 
D) protease. 
E) none of the above 
A) adapter protein. 
B) guanine nucleotide exchange protein. 
C) kinase. 
D) protease. 
E) none of the above

Question 20

Binding of hormone to a receptor tyrosine kinase causes all of the following,except:

Accepted Answer

A) dimerization of the receptor. 
B) autophosphorylation of the receptor. 
C) activation of Ras through an interaction with GRB2 and Sos. 
D) hydrolysis of GTP bound to Ras. 
A) dimerization of the receptor. 
B) autophosphorylation of the receptor. 
C) activation of Ras through an interaction with GRB2 and Sos. 
D) hydrolysis of GTP bound to Ras.

Exam 15: Signaling Pathways That Control Gene Activity

Transcriptional activation downstream of the MAPK pathway involves:

What feature distinguishes the ligand Delta from other ligands such as EGF,TGFα,and erythropoietin that bind transmembrane receptors?

Many kinases,including MAP kinase,protein kinase B,receptor tyrosine kinases,and JAKs,possess activation lips.What is an activation lip? What modification of the activation lip is required for activation of these kinases?

The order of events in a signaling pathway can be determined by the analysis of mutants.Cells that express a mutant defective Raf protein cannot be stimulated to proliferate uncontrollably by constitutively active Rasᴰ (dominant active).This indicates:

Which of the following receptors binds TGFβ?

Before ligand binding,receptor tyrosine kinases:

TGF- β normally promotes:

In which of the following double-mutant flies will R7 photoreceptors develop normally?

Ski and SnoN were originally identified as oncoproteins.Explain how constitutive expression of these proteins promotes cancer.

Which of the following is a protein kinase?

All genes regulated by PKA contain a cis-acting DNA sequence that binds to the phosphorylated form of a transcription factor called:

Which of the following explains why Ras is activated quickly by RTKs?

How does activation of protein kinase B promote cell survival?

Which of the following contain(s)an SH2 domain?

An SH2-containing protein contains a mutation that changes its binding pocket such that tyrosine and phosphotyrosine bind with equal affinity.As a result,MEK activity:

Describe the experimental approach used to determine the order of events in a signaling pathway.

Which of the following signaling pathways can be activated by cytokines?

How can multiple MAP kinase pathways be segregated when they share a common component?

The EGF receptor is a(n):

Binding of hormone to a receptor tyrosine kinase causes all of the following,except:

Chemical Foundations

Molecular Genetic Techniques

Protein Structure and Function

Culturing and Visualizing Cells

Fundamental Molecular Genetic Mechanisms

Bio-membrane Structure

Genes Genomics and Chromosomes

Transcriptional Control of Gene Expression

Post-Transcriptional Gene Control

Transmembrane Transport of Ions and Small Molecules

Cellular Energetics

Moving Proteins Into Membranes and Organelles

Vesicular Traffic, Secretion, and Endocytosis

Signal Transduction and G-Protein Coupled Receptors

Cell Organization and Movement I: Microfilaments

Cell Organization and Movement II: Microtubules and Intermediate Filaments

Regulating the Eukaryotic Cell Cycle

Integrating Cells Into Tissues

Cell Birth, Lineage, and Death

Nerve Cells

Immunology

Cancer

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