Question 1

Which of the following is not involved in signal transduction by the $\beta$-adrenergic receptor pathway?

Accepted Answer

A) ATP 
B) Cyclic AMP 
C) Cyclic GMP 
D) GTP 
E) All of the above are involved. 
A) ATP 
B) Cyclic AMP 
C) Cyclic GMP 
D) GTP 
E) All of the above are involved. C

Question 2

Which of the following is not true of integrins?

Accepted Answer

A) Integrins are rich in cysteines. 
B) Integrins are internalized following binding to external ligands. 
C) Integrins have more than one subunit. 
D) Integrins interact with Ca2+ ions. 
E) Integrins bind to extracellular matrix components such as collagen and heparan sulfate. 
A) Integrins are rich in cysteines. 
B) Integrins are internalized following binding to external ligands. 
C) Integrins have more than one subunit. 
D) Integrins interact with Ca2+ ions. 
E) Integrins bind to extracellular matrix components such as collagen and heparan sulfate. B

Question 3

Oncogenes are known that encode all of the following except:

Accepted Answer

A) cytoplasmic G proteins and protein kinases. 
B) DNA-dependent RNA polymerases. 
C) growth factors. 
D) secreted proteins. 
E) transmembrane protein receptors. 
A) cytoplasmic G proteins and protein kinases. 
B) DNA-dependent RNA polymerases. 
C) growth factors. 
D) secreted proteins. 
E) transmembrane protein receptors. B

Question 4

Which of the following statements concerning cyclin-dependent protein kinases is not correct?

Accepted Answer

A) Each type of cell contains one specific form (isozyme). 
B) Their activity fluctuates during the cell cycle. 
C) Their activity is regulated by changes in gene expression,protein phosphorylation,and proteolysis. 
D) Their activity is regulated by cyclins. 
E) They can alter the activity of proteins involved in the progression of cells through the cell cycle. 
A) Each type of cell contains one specific form (isozyme). 
B) Their activity fluctuates during the cell cycle. 
C) Their activity is regulated by changes in gene expression,protein phosphorylation,and proteolysis. 
D) Their activity is regulated by cyclins. 
E) They can alter the activity of proteins involved in the progression of cells through the cell cycle.

Question 5

Which of the following does not bind to heterotrimeric G proteins?

Accepted Answer

A) GTP-GDP exchange factors (GEFs) 
B) GTPase activating proteins (GAPs) 
C) GPCRs 
D) cGMP 
E) GDP 
A) GTP-GDP exchange factors (GEFs) 
B) GTPase activating proteins (GAPs) 
C) GPCRs 
D) cGMP 
E) GDP

Question 6

In the plant signaling pathways employing receptor-like kinases (RLKs),which one of the following does not occur?

Accepted Answer

A) Activation of a MAPK cascade 
B) Autophosphorylation of receptor 
C) Dimerization of receptor 
D) Ligand binding to receptor 
E) Phosphorylation of key proteins on Tyr residues 
A) Activation of a MAPK cascade 
B) Autophosphorylation of receptor 
C) Dimerization of receptor 
D) Ligand binding to receptor 
E) Phosphorylation of key proteins on Tyr residues

Question 7

Describe the role of G proteins in olfactory sensory transduction

Accepted Answer

When a sensory stimulant interacts with

Question 8

The specificity of signaling pathways includes all of the following except:

Accepted Answer

A) flippase-catalyzed movement of phospholipids from the inner to the outer leaflet. 
B) migration of signal proteins into membrane rafts. 
C) phosphorylation of target proteins at Ser,Thr,or Tyr residues. 
D) the ability to be switched off instantly by hydrolysis of a single phosphate-ester bond. 
E) the assembly of large multiprotein complexes. 
A) flippase-catalyzed movement of phospholipids from the inner to the outer leaflet. 
B) migration of signal proteins into membrane rafts. 
C) phosphorylation of target proteins at Ser,Thr,or Tyr residues. 
D) the ability to be switched off instantly by hydrolysis of a single phosphate-ester bond. 
E) the assembly of large multiprotein complexes.

Question 9

Which one of the following signaling mechanisms is used most predominantly in plants?

Accepted Answer

A) Cyclic-nucleotide dependent protein kinases 
B) DNA-binding nuclear steroid receptors 
C) G protein-coupled receptors 
D) Protein serine/threonine kinases 
E) Protein tyrosine kinases 
A) Cyclic-nucleotide dependent protein kinases 
B) DNA-binding nuclear steroid receptors 
C) G protein-coupled receptors 
D) Protein serine/threonine kinases 
E) Protein tyrosine kinases

Question 10

Explain how an increase in cytosolic Ca2+ concentration from 10-8 M to 10-6 M activates a Ca2+ and calmodulin-dependent enzyme.

Accepted Answer

The higher Ca²⁺ concentration allows Ca²⁺ bi

Question 11

Programmed cell death is called:

Accepted Answer

A) metastasis. 
B) apoptosis. 
C) mitotic termination. 
D) oncogenic transformation. 
E) ubiquitination. 
A) metastasis. 
B) apoptosis. 
C) mitotic termination. 
D) oncogenic transformation. 
E) ubiquitination.

Question 12

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 13

Briefly describe the key features of the voltage-gated Na+-ion channel found in neurons.

Accepted Answer

There are four homologous domains in the

Question 14

Explain how a mutation in the EGF receptor can lead to unregulated cell division.

Accepted Answer

The normal EGF receptor signals a cell t

Question 15

How do ligand-gated ion channels play a role in sensory transduction in the eye?

Accepted Answer

Rod and cone cells in the retina contain

Question 16

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

Question 17

The toxins produced by Bordetella pertussis (which causes whooping cough)and by Vibrio cholerae (which causes cholera)have similar modes of action in toxin-sensitive mammalian cells.Describe the molecular basis for their toxic effects.

Accepted Answer

Both toxins are enzymes that catalyze th

Question 18

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 above 
A) enzyme inhibitors. 
B) enzyme modifiers. 
C) enzymes. 
D) G protein signal transduction disrupters. 
E) All of the above

Question 19

Explain why mutations in oncogenes are generally dominant while those in tumor suppressor genes are recessive.

Accepted Answer

With oncogenes,the abnormal protein prod

Question 20

Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to:

Accepted Answer

A) diacylglycerol + inositol triphosphate. 
B) diacylglycerol + inositol+ phosphate. 
C) glycerol + inositol + phosphate. 
D) glycerol + phosphoserine. 
E) phosphatidyl glycerol + inositol + phosphate. 
A) diacylglycerol + inositol triphosphate. 
B) diacylglycerol + inositol+ phosphate. 
C) glycerol + inositol + phosphate. 
D) glycerol + phosphoserine. 
E) phosphatidyl glycerol + inositol + phosphate.

Exam 12: Biosignaling

Which of the following is not involved in signal transduction by the β\betaβ -adrenergic receptor pathway?

Which of the following is not true of integrins?

Oncogenes are known that encode all of the following except:

Which of the following statements concerning cyclin-dependent protein kinases is not correct?

Which of the following does not bind to heterotrimeric G proteins?

In the plant signaling pathways employing receptor-like kinases (RLKs),which one of the following does not occur?

Describe the role of G proteins in olfactory sensory transduction

The specificity of signaling pathways includes all of the following except:

Which one of the following signaling mechanisms is used most predominantly in plants?

Explain how an increase in cytosolic Ca2+ concentration from 10-8 M to 10-6 M activates a Ca2+ and calmodulin-dependent enzyme.

Programmed cell death is called:

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

Briefly describe the key features of the voltage-gated Na+-ion channel found in neurons.

Explain how a mutation in the EGF receptor can lead to unregulated cell division.

How do ligand-gated ion channels play a role in sensory transduction in the eye?

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

The toxins produced by Bordetella pertussis (which causes whooping cough)and by Vibrio cholerae (which causes cholera)have similar modes of action in toxin-sensitive mammalian cells.Describe the molecular basis for their toxic effects.

Cholera and pertussis toxins are:

Explain why mutations in oncogenes are generally dominant while those in tumor suppressor genes are recessive.

Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to:

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

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Principles of Bioenergetics

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

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Which of the following is not involved in signal transduction by the $\beta$ -adrenergic receptor pathway?

Explain how an increase in cytosolic Ca²⁺ concentration from 10^-8 M to 10^-6 M activates a Ca²⁺and calmodulin-dependent enzyme.

Briefly describe the key features of the voltage-gated Na⁺-ion channel found in neurons.