Question 1

Explain two different approaches to targeting the activity of aberrant protein kinases for treating cancer. Give examples of each.

Accepted Answer

One approach to targeting the activity o

Question 2

Steroid hormones are carried on specific carrier proteins because the hormones:

Accepted Answer

A)  are too unstable to survive in the blood on their own. 
B)  cannot dissolve readily in the blood because they are too hydrophobic. 
C)  cannot find their target cells without them. 
D)  need them in order to pass through the plasma membrane. 
E)  require subsequent binding to specific receptor proteins in the nucleus. 
A)  are too unstable to survive in the blood on their own. 
B)  cannot dissolve readily in the blood because they are too hydrophobic. 
C)  cannot find their target cells without them. 
D)  need them in order to pass through the plasma membrane. 
E)  require subsequent binding to specific receptor proteins in the nucleus.

Question 3

_____ is NOT involved in signal transduction by the $\beta$-adrenergic receptor pathway.

Accepted Answer

A)  Cyclic AMP synthesis 
B)  GTP hydrolysis 
C)  GTP-binding protein 
D)  Protein kinase 
E)  All of these are involved. 
A)  Cyclic AMP synthesis 
B)  GTP hydrolysis 
C)  GTP-binding protein 
D)  Protein kinase 
E)  All of these are involved.

Question 4

What is the CORRECT order for the following members of the MAP Kinase cascade? 1) MEK
2) ERK
3) Raf
4) RTK

Accepted Answer

A)  4, 2, 3, 1 
B)  2, 1, 3, 4 
C)  4, 3, 1, 2 
D)  4, 1, 2, 3 
E)  4, 3, 2, 1 
A)  4, 2, 3, 1 
B)  2, 1, 3, 4 
C)  4, 3, 1, 2 
D)  4, 1, 2, 3 
E)  4, 3, 2, 1

Question 5

Explain how amplification occurs in signal transductions with examples from all three of these systems: the $\beta$-adrenergic receptor, the insulin receptor, or the vasopressin system via inositol-1,4,5-trisphosphate (IP3).

Accepted Answer

Amplification in signal transduction occ

Question 6

How do G-proteins become deactivated?

Accepted Answer

A)  GDP dissociates from the $\alpha$ subunit. 
B)  GTP dissociates from the $\alpha$subunit. 
C)  ATP is converted to cAMP in the active site. 
D)  GTP is hydrolyzed to GDP. 
E)  GDP both dissociates from the $\alpha$ subunit and is hydrolyzed to GDP. 
A)  GDP dissociates from the $\alpha$ subunit. 
B)  GTP dissociates from the $\alpha$subunit. 
C)  ATP is converted to cAMP in the active site. 
D)  GTP is hydrolyzed to GDP. 
E)  GDP both dissociates from the $\alpha$ subunit and is hydrolyzed to GDP.

Question 7

The G protein involved in visual signal transduction is:

Accepted Answer

A)  a leukotriene. 
B)  transducin. 
C)  arrestin. 
D)  rhodopsin. 
E)  a GTP receptor. 
A)  a leukotriene. 
B)  transducin. 
C)  arrestin. 
D)  rhodopsin. 
E)  a GTP receptor.

Question 8

The effects of acetylcholine on the postsynaptic ion channel are mainly due to:

Accepted Answer

A)  cyclic nucleotide synthesis. 
B)  protein cleavage (proteolysis). 
C)  protein conformational changes. 
D)  protein phosphorylation. 
E)  protein synthesis. 
A)  cyclic nucleotide synthesis. 
B)  protein cleavage (proteolysis). 
C)  protein conformational changes. 
D)  protein phosphorylation. 
E)  protein synthesis.

Question 9

Explain how amplification of a hormonal signal takes place; illustrate with a specific example.

Accepted Answer

Amplification of a hormonal signal occur

Question 10

What are cyclins? What is their role in the regulation of the cell cycle?

Accepted Answer

Cyclins are a family of proteins that pl

Question 11

Which statement concerning receptor enzymes is CORRECT?

Accepted Answer

A)  They are not usually membrane-associated proteins. 
B)  They contain an enzyme activity that acts on a cytosolic substrate. 
C)  They contain an enzyme activity that acts on the extracellular ligand. 
D)  They have a ligand-binding site on the cytosolic side of the membrane. 
E)  They have an active site on the extracellular side of the membrane. 
A)  They are not usually membrane-associated proteins. 
B)  They contain an enzyme activity that acts on a cytosolic substrate. 
C)  They contain an enzyme activity that acts on the extracellular ligand. 
D)  They have a ligand-binding site on the cytosolic side of the membrane. 
E)  They have an active site on the extracellular side of the membrane.

Question 12

Autophosphorylation of receptor tyrosine kinases depends on:

Accepted Answer

A)  dimerization of the receptor. 
B)  ATP. 
C)  ligand binding. 
D)  transmission of conformational changes through the membrane. 
E)  All of the answers are correct. 
A)  dimerization of the receptor. 
B)  ATP. 
C)  ligand binding. 
D)  transmission of conformational changes through the membrane. 
E)  All of the answers are correct.

Question 13

Most transduction systems for hormones and sensory stimuli that involve trimeric G proteins do NOT have _____ in common.

Accepted Answer

A)  cyclic nucleotides 
B)  nuclear receptors 
C)  receptors that interact with a G protein 
D)  receptors with multiple transmembrane segments 
E)  self-inactivation 
A)  cyclic nucleotides 
B)  nuclear receptors 
C)  receptors that interact with a G protein 
D)  receptors with multiple transmembrane segments 
E)  self-inactivation

Question 14

Compare and contrast the modes of action of epinephrine, acting through the $\beta$-adrenergic receptor, and of insulin, acting through the insulin receptor.

Accepted Answer

Epinephrine and insulin are two hormones

Question 15

Which item does NOT use a cAMP-dependent signaling pathway?

Accepted Answer

A)  insulin 
B)  epinephrine 
C)  ddorants 
D)  spicy tastes 
E)  growth factors 
A)  insulin 
B)  epinephrine 
C)  ddorants 
D)  spicy tastes 
E)  growth factors

Question 16

Which factor is NOT a shared feature of signaling by mammalian vision and gustatory receptor pathways?

Accepted Answer

A)  changes in cAMP levels 
B)  GDP/GTP exchange 
C)  heterotrimeric G proteins 
D)  open/closing of ion channels 
E)  transmembrane receptors 
A)  changes in cAMP levels 
B)  GDP/GTP exchange 
C)  heterotrimeric G proteins 
D)  open/closing of ion channels 
E)  transmembrane receptors

Question 17

Cholera and pertussis toxins are:

Accepted Answer

A)  enzyme inhibitors. 
B)  enzyme modifiers. 
C)  enzymes. 
D)  G-protein signal transduction disrupters. 
E)  All of the answers are correct. 
A)  enzyme inhibitors. 
B)  enzyme modifiers. 
C)  enzymes. 
D)  G-protein signal transduction disrupters. 
E)  All of the answers are correct.

Question 18

If a FRET experiment was carried out with blue fluorescent protein attached to the $\alpha$ subunit of a stimulatory G-protein and a green fluorescent protein attached to the $\beta$ subunit, the presence of a strong FRET signal would be associated with:

Accepted Answer

A)  interaction of a G protein-coupled receptor with an antagonist. 
B)  hydrolysis of GTP in the $\alpha$ subunit. 
C)  increased concentrations of cAMP. 
D)  both interaction of a G protein-coupled receptor with an antagonist and hydrolysis of GTP in the $\alpha$subunit. 
E)  both hydrolysis of GTP in the $\alpha$ subunit and increased concentrations of cAMP. 
A)  interaction of a G protein-coupled receptor with an antagonist. 
B)  hydrolysis of GTP in the $\alpha$ subunit. 
C)  increased concentrations of cAMP. 
D)  both interaction of a G protein-coupled receptor with an antagonist and hydrolysis of GTP in the $\alpha$subunit. 
E)  both hydrolysis of GTP in the $\alpha$ subunit and increased concentrations of cAMP.

Exam 12: Biosignaling

Explain two different approaches to targeting the activity of aberrant protein kinases for treating cancer. Give examples of each.

Steroid hormones are carried on specific carrier proteins because the hormones:

_____ is NOT involved in signal transduction by the β\betaβ -adrenergic receptor pathway.

What is the CORRECT order for the following members of the MAP Kinase cascade? 1) MEK 2) ERK 3) Raf 4) RTK

Explain how amplification occurs in signal transductions with examples from all three of these systems: the β\betaβ -adrenergic receptor, the insulin receptor, or the vasopressin system via inositol-1,4,5-trisphosphate (IP3).

How do G-proteins become deactivated?

The G protein involved in visual signal transduction is:

The effects of acetylcholine on the postsynaptic ion channel are mainly due to:

Explain how amplification of a hormonal signal takes place; illustrate with a specific example.

What are cyclins? What is their role in the regulation of the cell cycle?

Which statement concerning receptor enzymes is CORRECT?

Autophosphorylation of receptor tyrosine kinases depends on:

Most transduction systems for hormones and sensory stimuli that involve trimeric G proteins do NOT have _____ in common.

Compare and contrast the modes of action of epinephrine, acting through the β\betaβ -adrenergic receptor, and of insulin, acting through the insulin receptor.

Which item does NOT use a cAMP-dependent signaling pathway?

Which factor is NOT a shared feature of signaling by mammalian vision and gustatory receptor pathways?

Cholera and pertussis toxins are:

If a FRET experiment was carried out with blue fluorescent protein attached to the α\alphaα subunit of a stimulatory G-protein and a green fluorescent protein attached to the β\betaβ subunit, the presence of a strong FRET signal would be associated with:

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

_____ is NOT involved in signal transduction by the $\beta$ -adrenergic receptor pathway.

Explain how amplification occurs in signal transductions with examples from all three of these systems: the $\beta$ -adrenergic receptor, the insulin receptor, or the vasopressin system via inositol-1,4,5-trisphosphate (IP₃).

Compare and contrast the modes of action of epinephrine, acting through the $\beta$ -adrenergic receptor, and of insulin, acting through the insulin receptor.

If a FRET experiment was carried out with blue fluorescent protein attached to the $\alpha$ subunit of a stimulatory G-protein and a green fluorescent protein attached to the $\beta$ subunit, the presence of a strong FRET signal would be associated with: