Question 1

Glucocorticoids are thought to function as anti-inflammatory agents since they are able to stimulate the synthesis of what protein?

Accepted Answer

A) tumor necrosis factor (TNF) 
B) platelet-derived growth factor (PDGF) 
C) transforming growth factor $\beta$ (TGF-$\beta$) 
D) nuclear factor-kappa B (NF-$\kappa$
B)  
E) inhibitor-kappa B$\alpha$ (I$\kappa$B$\alpha$) 
A) tumor necrosis factor (TNF) 
B) platelet-derived growth factor (PDGF) 
C) transforming growth factor $\beta$ (TGF-$\beta$) 
D) nuclear factor-kappa B (NF-$\kappa$
B)  
E) inhibitor-kappa B$\alpha$ (I$\kappa$B$\alpha$) E

Question 2

The complex of zinc and cysteine residues seen in the structure of steroid hormone receptors is referred to as a(an)______________ structural motif.

Accepted Answer

A) zinc loop 
B) zinc helix 
C) antiparallel zinc sheet 
D) zinc finger 
E) zinc turn 
A) zinc loop 
B) zinc helix 
C) antiparallel zinc sheet 
D) zinc finger 
E) zinc turn D

Question 3

The enkephalins, along with $\beta$-endorphin, bind to the opioid receptor, so named because the opiate drugs such as __________ bind to it with high affinity

Accepted Answer

A) morphine 
B) fluoxetine (Prozac) 
C) phencyclidine 
D) methyl phenidylacetate (Ritalin) 
E) lysergic acid diethylamide (LS
D)  
A) morphine 
B) fluoxetine (Prozac) 
C) phencyclidine 
D) methyl phenidylacetate (Ritalin) 
E) lysergic acid diethylamide (LS
D)  A

Question 4

The structures of isoproterenol (left)and epinephrine are shown below. What is isoproterenol?

Accepted Answer

A) agonist 
B) antagonist 
C) inverse agonist 
D) irreversible agonist 
E) non-competitive antagonist 
A) agonist 
B) antagonist 
C) inverse agonist 
D) irreversible agonist 
E) non-competitive antagonist

Question 5

What happens when the GTPase activity of a G protein is blocked?

Accepted Answer

A) the $\alpha$ subunit associates only with the $\beta$ subunit, not the $\gamma$subunit 
B) GTP cyclizes to cGMP 
C) binding to GAP occurs with very high affinity 
D) adenylate cyclase remains active 
E) none of the above 
A) the $\alpha$ subunit associates only with the $\beta$ subunit, not the $\gamma$subunit 
B) GTP cyclizes to cGMP 
C) binding to GAP occurs with very high affinity 
D) adenylate cyclase remains active 
E) none of the above

Question 6

What neurotransmitter is involved with cholinergic synapses?

Accepted Answer

A) serotonin 
B) dopamine 
C) acetylcholine 
D) glutamate 
E) $\gamma$-aminobutyric acid 
A) serotonin 
B) dopamine 
C) acetylcholine 
D) glutamate 
E) $\gamma$-aminobutyric acid

Question 7

In the presynaptic neuron, ______ influx causes neurotransmitter release while in the postsynaptic neuron, ______ enters the cell following opening of ion channels.

Accepted Answer

A) Na+; K+ 
B) K+; Na+ 
C) Ca2+; K+ 
D) Ca2+; Na+ 
E) Na+; Ca2+ 
A) Na+; K+ 
B) K+; Na+ 
C) Ca2+; K+ 
D) Ca2+; Na+ 
E) Na+; Ca2+

Question 8

When a nerve cell terminates at a muscle cell, the action potential causes opening of _____ channels that results in muscle contraction.

Accepted Answer

A) Na+ 
B) K+ 
C) Ca2+ 
D) Cl- 
E) none of the above 
A) Na+ 
B) K+ 
C) Ca2+ 
D) Cl- 
E) none of the above

Question 9

What amino acid is the source of carbon for the synthesis of ethylene in plants?

Accepted Answer

A) glycine 
B) serine 
C) aspartate 
D) methionine 
E) alanine 
A) glycine 
B) serine 
C) aspartate 
D) methionine 
E) alanine

Question 10

InsP3 binds to _______ channels in the endoplasmic reticulum while DAG activates ___________.

Accepted Answer

A) Na+; protein kinase A 
B) Na+; protein kinase C 
C) Ca2+; protein kinase A 
D) Ca2+; protein kinase C 
E) none of the above 
A) Na+; protein kinase A 
B) Na+; protein kinase C 
C) Ca2+; protein kinase A 
D) Ca2+; protein kinase C 
E) none of the above

Question 11

Most steroid hormones exert their effects by initial binding to which of the following receptors?

Accepted Answer

A) receptor in cell membrane 
B) receptor in cytosol 
C) receptor in nuclear membrane 
D) receptor in nucleus 
E) none of the above 
A) receptor in cell membrane 
B) receptor in cytosol 
C) receptor in nuclear membrane 
D) receptor in nucleus 
E) none of the above

Question 12

Inside a cell, glucagon ultimately results in the phosphorylation of a wide variety of enzymes to control their activity. For each of the following enzymes that is phosphorylated in response to glucagon binding, explain what happens to its activity and why that is important (considering the pathway that the enzyme is in and the overall goal of glucagon).
Acetyl-CoA carboxylase:
Pyruvate kinase:
Glycogen phosphorylase:
Phosphofructokinase-2:

Accepted Answer

Acetyl-CoA carboxylase: is inhibited. Th

Question 13

Show the reaction of phospholipase C upon PIP2 and give the names of the products.

Accepted Answer

diacylglycerol (DAG)

Question 14

In the visual process, activated rhodopsin causes which of the following events to occur?

Accepted Answer

A) transducin binding to GTP 
B) transducin binding to GDP 
C) transducin binding to cGMP 
D) transducin binding to GMP 
E) none of the above 
A) transducin binding to GTP 
B) transducin binding to GDP 
C) transducin binding to cGMP 
D) transducin binding to GMP 
E) none of the above

Question 15

Insulin activates glycogen synthase while glucagon inhibits glycogen synthase. Explain the intracellular mechanisms that are used to bring about this activity.

Accepted Answer

Glucagon binds to its receptor causing a

Question 16

What is the primary target of releasing factors from the hypothalamus?

Accepted Answer

A) thyroid 
B) adrenal medulla 
C) adrenal cortex 
D) posterior pituitary 
E) anterior pituitary 
A) thyroid 
B) adrenal medulla 
C) adrenal cortex 
D) posterior pituitary 
E) anterior pituitary

Question 17

The principle inhibitory neurotransmitter, __________, works by triggering an influx of ______ causing hyperpolarization of nerve cells.

Accepted Answer

A) $\gamma$-aminobutyric acid; K+ 
B) $\gamma$-aminobutyric acid; Cl- 
C) serotonin; K+ 
D) serotonin; Cl- 
E) none of the above 
A) $\gamma$-aminobutyric acid; K+ 
B) $\gamma$-aminobutyric acid; Cl- 
C) serotonin; K+ 
D) serotonin; Cl- 
E) none of the above

Question 18

Which second messenger is produced as a result of nitric oxide binding?

Accepted Answer

A) cAMP 
B) cGMP 
C) PIP2 
D) InsP3 
E) DAG 
A) cAMP 
B) cGMP 
C) PIP2 
D) InsP3 
E) DAG

Question 19

Which of the following signaling molecules activate the phosphoinositide second messenger system?

Accepted Answer

A) platelet-derived growth factor 
B) acetylcholine 
C) vasopressin 
D) thyrotropin-releasing hormone 
E) all of the above 
A) platelet-derived growth factor 
B) acetylcholine 
C) vasopressin 
D) thyrotropin-releasing hormone 
E) all of the above

Question 20

Like G proteins, the Ras protein binds _______ when in its active state which is hydrolyzed to ______ to convert the protein to its inactive state.

Accepted Answer

A) GTP; GDP 
B) GTP; GMP 
C) GMP; cGMP 
D) cGMP; GMP 
E) cGMP; GDP 
A) GTP; GDP 
B) GTP; GMP 
C) GMP; cGMP 
D) cGMP; GMP 
E) cGMP; GDP

Exam 23: Mechanisms of Signal Transduction

Glucocorticoids are thought to function as anti-inflammatory agents since they are able to stimulate the synthesis of what protein?

The complex of zinc and cysteine residues seen in the structure of steroid hormone receptors is referred to as a(an)______________ structural motif.

The enkephalins, along with β\betaβ -endorphin, bind to the opioid receptor, so named because the opiate drugs such as __________ bind to it with high affinity

The structures of isoproterenol (left)and epinephrine are shown below. What is isoproterenol?

What happens when the GTPase activity of a G protein is blocked?

What neurotransmitter is involved with cholinergic synapses?

In the presynaptic neuron, ______ influx causes neurotransmitter release while in the postsynaptic neuron, ______ enters the cell following opening of ion channels.

When a nerve cell terminates at a muscle cell, the action potential causes opening of _____ channels that results in muscle contraction.

What amino acid is the source of carbon for the synthesis of ethylene in plants?

InsP3 binds to _______ channels in the endoplasmic reticulum while DAG activates ___________.

Most steroid hormones exert their effects by initial binding to which of the following receptors?

Show the reaction of phospholipase C upon PIP2 and give the names of the products.

In the visual process, activated rhodopsin causes which of the following events to occur?

Insulin activates glycogen synthase while glucagon inhibits glycogen synthase. Explain the intracellular mechanisms that are used to bring about this activity.

What is the primary target of releasing factors from the hypothalamus?

The principle inhibitory neurotransmitter, __________, works by triggering an influx of ______ causing hyperpolarization of nerve cells.

Which second messenger is produced as a result of nitric oxide binding?

Which of the following signaling molecules activate the phosphoinositide second messenger system?

Like G proteins, the Ras protein binds _______ when in its active state which is hydrolyzed to ______ to convert the protein to its inactive state.

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars, Saccharides, Glycans

Lipids, Membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, Oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids, Triacylglycerols, and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, Steroids, Isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, Utilization, and Turnover

Metabolism of Nitogenous Compounds II: Amino Acids, Porphyrins, and Neurotransmitters

Nucleotide Metabolism

Genes, Genomes and Chromosomes

DNA Replication

DNA Restructuring: Repair, Recombination, Rearrangement, Amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

The enkephalins, along with $\beta$ -endorphin, bind to the opioid receptor, so named because the opiate drugs such as __________ bind to it with high affinity

In the presynaptic neuron, influx causes neurotransmitter release while in the postsynaptic neuron, enters the cell following opening of ion channels.

InsP₃ binds to _ channels in the endoplasmic reticulum while DAG activates _____.

Show the reaction of phospholipase C upon PIP₂ and give the names of the products.

The principle inhibitory neurotransmitter, ____, works by triggering an influx of causing hyperpolarization of nerve cells.

Like G proteins, the Ras protein binds _ when in its active state which is hydrolyzed to to convert the protein to its inactive state.