Question 1

Guanyl cyclase receptor enzymes:

Accepted Answer

A)  are all membrane-spanning proteins. 
B)  are examples of ligand-gated ion channels. 
C)  catalyze synthesis of a phosphate ester. 
D)  catalyze synthesis of a phosphoric acid anhydride 
E)  require hydrolysis of ATP in addition to GTP. 
A)  are all membrane-spanning proteins. 
B)  are examples of ligand-gated ion channels. 
C)  catalyze synthesis of a phosphate ester. 
D)  catalyze synthesis of a phosphoric acid anhydride 
E)  require hydrolysis of ATP in addition to GTP.

Question 2

Scatchard analysis can provide information on:

Accepted Answer

A)  enzyme cascades. 
B)  enzyme mechanisms. 
C)  gated ion channels. 
D)  protein phosphorylation. 
E)  receptor-ligand interactions. 
A)  enzyme cascades. 
B)  enzyme mechanisms. 
C)  gated ion channels. 
D)  protein phosphorylation. 
E)  receptor-ligand interactions.

Question 3

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

Accepted Answer

The voltage-gated Na-ion channel found i

Question 4

Signals carried by hormones must eventually be terminated; the response continues for a limited time. Discuss three different mechanisms for signal termination, using specific systems as examples.

Accepted Answer

One mechanism for terminating hormone si

Question 5

In the two-component signaling mechanism in E. coli chemotaxis, which amino acid is phosphorylated?

Accepted Answer

A)  serine 
B)  histidine 
C)  aspartate 
D)  threonine 
E)  both histidine and aspartate 
A)  serine 
B)  histidine 
C)  aspartate 
D)  threonine 
E)  both histidine and aspartate

Question 6

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

Accepted Answer

A mutation in the EGF receptor can lead

Question 7

Salbutamol is an epinephrine agonist for the $\beta$-adrenergic receptor. What effects would you expect to see if you treat a hepatocyte with salbutamol?

Accepted Answer

A)  inactivation of adenylylcyclase 
B)  activation of glycolysis 
C)  activation of glycogenolysis 
D)  glucose export from cells 
E)  both activation of glycogenolysis and glucose export from cells 
A)  inactivation of adenylylcyclase 
B)  activation of glycolysis 
C)  activation of glycogenolysis 
D)  glucose export from cells 
E)  both activation of glycogenolysis and glucose export from cells

Question 8

After membrane depolarization in neurons, export of potassium:

Accepted Answer

A)  makes the value of Vm more negative. 
B)  decreases the concentration gradient for potassium. 
C)  is energetically favourable. 
D)  All of the answers are correct. 
E)  None of the answers is correct. 
A)  makes the value of Vm more negative. 
B)  decreases the concentration gradient for potassium. 
C)  is energetically favourable. 
D)  All of the answers are correct. 
E)  None of the answers is correct.

Question 9

Briefly describe the key features of the acetylcholine receptor channel.

Accepted Answer

The acetylcholine receptor channel is a

Question 10

Glycogen synthase kinase (GSK3):

Accepted Answer

A)  is inhibited by phosphorylation of a tyrosine in GSK3. 
B)  inhibits glycogen synthase. 
C)  is a tyrosine kinase. 
D)  is both inhibited by phosphorylation of a tyrosine in GSK3 and is a tyrosine kinase. 
E)  both inhibits glycogen synthase and is a tyrosine kinase. 
A)  is inhibited by phosphorylation of a tyrosine in GSK3. 
B)  inhibits glycogen synthase. 
C)  is a tyrosine kinase. 
D)  is both inhibited by phosphorylation of a tyrosine in GSK3 and is a tyrosine kinase. 
E)  both inhibits glycogen synthase and is a tyrosine kinase.

Question 11

Which compound(s) is/are involved in desensitization of the $\beta$-adrenergic receptor?

Accepted Answer

A) $\beta$-adrenergic receptor kinase 
B)  arrestin 
C)  GTPase activating proteins (GAPs) 
D)  both $\beta$-adrenergic receptor kinase and arrestin 
E)  $\beta$-adrenergic receptor kinase, arrestin, and GTPase activating proteins (GAPs) 
A) $\beta$-adrenergic receptor kinase 
B)  arrestin 
C)  GTPase activating proteins (GAPs) 
D)  both $\beta$-adrenergic receptor kinase and arrestin 
E)  $\beta$-adrenergic receptor kinase, arrestin, and GTPase activating proteins (GAPs)

Question 12

The ion channel that opens in response to acetylcholine is an example of a _____ signal transduction system.

Accepted Answer

A)  G-protein 
B)  ligand-gated 
C)  receptor-enzyme 
D)  serpentine receptor 
E)  voltage-gated 
A)  G-protein 
B)  ligand-gated 
C)  receptor-enzyme 
D)  serpentine receptor 
E)  voltage-gated

Question 13

Which characteristic is NOT one attributed to a second messenger?

Accepted Answer

A)  intracellular signaling molecules 
B)  molecules that can easily pass across membrane bilayers 
C)  molecules that can act as allosteric effectors for signaling proteins 
D)  molecules that can be rapidly converted between active and inactive forms 
E)  molecules that are synthesized in response to receptor/signal interactions 
A)  intracellular signaling molecules 
B)  molecules that can easily pass across membrane bilayers 
C)  molecules that can act as allosteric effectors for signaling proteins 
D)  molecules that can be rapidly converted between active and inactive forms 
E)  molecules that are synthesized in response to receptor/signal interactions

Question 14

Describe two examples of steroid hormone action that occur too rapidly to be the consequence of altered levels of protein synthesis.

Accepted Answer

One example of rapid steroid hormone act

Question 15

SH2 domains bind sequences containing:

Accepted Answer

A)  phosphoserine 
B)  phosphothreonine. 
C)  phosphotyrosine. 
D)  multiple phosphorylations. 
E)  either phosphoserine or phosphothreonine. 
A)  phosphoserine 
B)  phosphothreonine. 
C)  phosphotyrosine. 
D)  multiple phosphorylations. 
E)  either phosphoserine or phosphothreonine.

Question 16

Why is estrogen associated with carrier proteins in the blood?

Accepted Answer

A)  Carrier proteins are necessary to import estrogen into cells. 
B)  Estrogen has only limited solubility in the bloodstream. 
C)  Estrogen is very unstable in the blood. 
D)  The carrier proteins bind with estrogen to receptors. 
A)  Carrier proteins are necessary to import estrogen into cells. 
B)  Estrogen has only limited solubility in the bloodstream. 
C)  Estrogen is very unstable in the blood. 
D)  The carrier proteins bind with estrogen to receptors.

Question 17

Steriod hormone response elements (HREs) are _____, which, when bound to _____, alter gene expession at the level of _____.

Accepted Answer

A)  intron sequences; activated hormone receptor; translation 
B)  nuclear proteins; hormone; transcription 
C)  plasma membrane proteins; hormone; transcription 
D)  sequences in DNA; receptor-hormone complex; replication 
E)  sequences in DNA; receptor-hormone complex; transcription 
A)  intron sequences; activated hormone receptor; translation 
B)  nuclear proteins; hormone; transcription 
C)  plasma membrane proteins; hormone; transcription 
D)  sequences in DNA; receptor-hormone complex; replication 
E)  sequences in DNA; receptor-hormone complex; transcription

Question 18

Which statement BEST describes the concept of "amplification" in biosignaling?

Accepted Answer

A)  Higher concentrations of signal molecules lead to stronger cellular responses. 
B)  In response to the presence of a signal molecule, more signal molecules are synthesized. 
C)  Small amounts of extracellular signal will trigger multiple intracellular effects via enzyme cascades. 
D)  All of the statements describe this concept. 
E)  None of the statements describes this concept. 
A)  Higher concentrations of signal molecules lead to stronger cellular responses. 
B)  In response to the presence of a signal molecule, more signal molecules are synthesized. 
C)  Small amounts of extracellular signal will trigger multiple intracellular effects via enzyme cascades. 
D)  All of the statements describe this concept. 
E)  None of the statements describes this concept.

Question 19

Ubiquitin is a:

Accepted Answer

A)  component of the electron transport system. 
B)  protease. 
C)  protein kinase. 
D)  protein phosphorylase. 
E)  protein that tags another protein for proteolysis. 
A)  component of the electron transport system. 
B)  protease. 
C)  protein kinase. 
D)  protein phosphorylase. 
E)  protein that tags another protein for proteolysis.

Question 20

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.

Exam 12: Biosignaling

Guanyl cyclase receptor enzymes:

Scatchard analysis can provide information on:

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

Signals carried by hormones must eventually be terminated; the response continues for a limited time. Discuss three different mechanisms for signal termination, using specific systems as examples.

In the two-component signaling mechanism in E. coli chemotaxis, which amino acid is phosphorylated?

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

Salbutamol is an epinephrine agonist for the β\betaβ -adrenergic receptor. What effects would you expect to see if you treat a hepatocyte with salbutamol?

After membrane depolarization in neurons, export of potassium:

Briefly describe the key features of the acetylcholine receptor channel.

Glycogen synthase kinase (GSK3):

Which compound(s) is/are involved in desensitization of the β\betaβ -adrenergic receptor?

The ion channel that opens in response to acetylcholine is an example of a _____ signal transduction system.

Which characteristic is NOT one attributed to a second messenger?

Describe two examples of steroid hormone action that occur too rapidly to be the consequence of altered levels of protein synthesis.

SH2 domains bind sequences containing:

Why is estrogen associated with carrier proteins in the blood?

Steriod hormone response elements (HREs) are _____, which, when bound to _____, alter gene expession at the level of _____.

Which statement BEST describes the concept of "amplification" in biosignaling?

Ubiquitin is a:

Programmed cell death is called:

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

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

Salbutamol is an epinephrine agonist for the $\beta$ -adrenergic receptor. What effects would you expect to see if you treat a hepatocyte with salbutamol?

Which compound(s) is/are involved in desensitization of the $\beta$ -adrenergic receptor?

Steriod hormone response elements (HREs) are ___, which, when bound to _, alter gene expession at the level of ___.