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Q:
Convert 5.100 10-3 to ordinary notation.
A) 0.0005100
B) 0.005100
C) 510.0
D) 5100
Q:
The factor 10-2 corresponds to which prefix?
A) deka
B) deci
C) centi
D) milli
Q:
The factor 0.01 corresponds to which prefix?
A) deka
B) deci
C) centi
D) milli
Q:
What symbol is used to represent the factor 10-9?A) MB) mC) D) n
Q:
What symbol is used to represent the factor 10-3?A) MB) mC) D) n
Q:
What symbol is used to express the factor, 10-6?A) MB) mC) D) n
Q:
All of the following are fundamental SI units except the
A) gram.
B) Kelvin.
C) meter.
D) second.
Q:
Which of the following is a fundamental SI Unit?
A) centimeter
B) kilogram
C) microsecond
D) milliliter
Q:
The fundamental SI unit of mass is the
A) centigram.
B) gram.
C) kilogram.
D) milligram.
Q:
An interpretation of the results of many tests is called
A) an experiment.
B) a hypothesis.
C) a prediction.
D) a theory.
Q:
A consistent explanation of known observations is called
A) an experiment.
B) a hypothesis.
C) a prediction.
D) a theory.
Q:
A specific GTPase-activating protein (GAP) binds to and activates:
a. the G-protein.
b. the plasma membrane receptor.
c. adenylyl cyclase.
d. the GTPase activity of the Ras protein.
e. none of the above.
Q:
The amount of cAMP generated in the cytoplasm is dependent on the:
a. activity of adenylyl cyclase only.
b. activity of the phosphodiesterase only.
c. the length of time the GTP remains bound to the Gï¡-protein only.
d. all of the above.
e. none of the above.
Q:
The binding of hormone to G-protein coupled receptor stimulates the sequence:a. B, C, A, D, Eb. C, E, A, D, Bc. C, E, B, D, Ad. D, A, C, E, Be. E, A, D, B, C
Q:
In G-proteins, binding of GTP causes which of the following to occur?
Q:
Nitroglycerine is a potent ____ because of the release of ____.
a. antioxidant; O2
b. vasoconstrictor; NO.
c. vasodilator; NO.
d. muscle tensor; O2
e. all are true
Q:
How does extracellular hormone binding activate intracellular tyrosine kinase activity?
a. conformational change induced active site activation
b. conformational change induced oligomeric association and phosphorylation
c. induced mRNA synthesis
d. activation of specific phospholipases
e. all are true
Q:
The insulin receptor is in what class of tyrosine kinase receptors?
a. Class I with 2 Cys-rich repeat sequences
b. Class II with a2b2 tetrameric structure
c. Class III with multiple immunoglobulin-like extracellular domains
d. Class IV with a glycosylated protein domain
e. Class V with a lipid-rich hydrophobic domain
Q:
All are domains of receptor tyrosine kinase EXCEPT:a. adenylyl cyclase activity domain.b. glycosylated extracellular receptor-binding domain.c. a single transmembrane -helix.d. intracellular tyrosine kinase domain.e. regulatory domain with phosphorylation sites.
Q:
Receptor tyrosine kinases have been called ____ as a result of their ____ and ____.
a. membrane-associated allosteric enzymes; induced conformation changes; oligomeric interactions
b. adrenergic receptors; binding insulin; binding epinephrine
c. GTP-binding proteins; GTPase activity; guanylyl cyclase activity
d. multi-TMS receptors; complex structure; G-protein binding
e. none of the above
Q:
All are components of the G-protein-coupled receptors (GPCRs) hormone signal transduction unit EXCEPT:
a. protein kinase A.
b. adenylyl cyclase.
c. hormone receptor.
d. G-protein.
e. all of the above.
Q:
G-proteins are associated with which receptor superfamily?
a. oligomeric ligand-gated ion channels
b. 7-transmembrane segment (7-TMS) receptors
c. cell adhesion protein receptors
d. single-transmembrane segment catalytic receptors
e. none of the above
Q:
All are enzymes in the enzyme cascade for activation of glycogen phosphorylase EXCEPT:
a. adenylyl cyclase.
b. protein kinase A.
c. hormone sensitive lipase.
d. phosphorylase kinase.
e. all are in the cascade.
Q:
Which of the following doe NOT correctly pair a hormone with its function?a. ACTH - promotes production of thyroxinb. calcitonin - regulates plasma Ca2+c. FSH - stimulates processes within the gonadsd. insulin - regulates metabolism and blood glucosee. prolactin - stimulates milk production
Q:
The acrosome reaction, involving ion channel induced release of acrosomal enzymes used by sperm to attack the egg, is induced by:
a. estrogen.
b. testosterone.
c. dihydrotestosterone (DHT).
d. progesterone.
e. cortisol.
Q:
Each of the following statements is true EXCEPT:
a. epinephrine is an amino acid derivative
b. steroid hormones can enter cells and regulate transcription
c. insulin is a polypeptide hormone
d. progesterone is a polypeptide hormone
e. all of the above are true
Q:
All are unifying features of polypeptide hormones EXCEPT that they are:
a. originally synthesized with signal sequences.
b. synthesized as inactive preprohormones.
c. activated from preprohormones to hormones by phosphorylation.
d. may produce several different peptide hormones with suitable processing.
e. all are true.
Q:
Steroid hormones, such as glucocorticoids, effect their action by:
a. binding to a plasma membrane receptor, which stimulates a signal transduction pathway within the cell
b. binding to a plasma membrane receptor, which stimulates the receptor to enter the cell
c. entering into the cell and affecting the production of secondary messengers
d. entering into the cell and then acting as transcription regulators
e. both a and d are correct
Q:
Hormones and other signal molecules bind with ____ affinities to their receptors and are produced at concentrations ____ their KDvalues.
a. low; far above
b. moderate; far above
c. moderate; equivalent to
d. high; far below
e. very high; equivalent to
Q:
Which of the following is a G-protein coupled receptor?a. EGF receptorb. insulin receptorc. atrial natriuretic peptide receptord. inhibitory 2-receptore. EPO receptor
Q:
Which of the following is NOT a second messenger?
a. cGMP
b. norepinephrine
c. nitric oxide
d. diacylglycerol
e. Ca2+
Q:
Which of the following is NOT an event that would occur upon the binding of a hormone to a receptor?
a. a second messenger such as cAMP might be produced
b. inositol triphosphate causes the release of potassium from the ER
c. protein kinase C is activated by DAG
d. tyrosine kinase receptors dimerize and undergo phosphorylation
e. all of the above occur
Q:
Across a normal cellular membrane, the potential is maintained with a positive charge on the outside of the cell and a negative charge on the inside of the cell. Which of the following best explains the operation of the voltage sensor in the voltage-gated sodium channel?
a. Under resting cellular conditions, the voltage sensor is normally pulled to the inside of the cell due to its high arginine content
b. Under resting cellular conditions, the voltage sensor is normally pulled to the outside of the cell due to its high lysine content
c. When the membrane is depolarized, the voltage sensor moves towards the outside of the membrane, allowing opening of the activation gate
d. Both a and c occur
e. None of the above
Q:
Which of the following is true regarding the GTPase activity of Ras proteins?
a. under normal conditions, the GTPase activity is very high with most Ras proteins kept in an inactive state
b. Ras proteins have no inherent GTPase activity and rely upon the binding of GTPase-activating protein
c. mutations of the Ras protein cause GTPase activity to be extremely low
d. the GTPase-activating protein is inhibited by cAMP
e. none of the above
Q:
Which of the following is not a peptide hormone?
a. adrenocorticotropic hormone
b. glucagon
c. aldosterone
d. calcitonin
e. all of the above are peptide hormones
Q:
A muscarinic receptor is a subclass of ____ receptor, and can be inhibited by ____.
a. GABA; atropine
b. GABA; acetylcholine
c. acetylcholine; GABA
d. acetylcholine; atropine
e. acetylcholine; muscarine
Q:
____ act as an antidepressant by ____ levels of catacholamines in the brain.
a. Tricyclics; increasing
b. Tricyclics; decreasing
c. Monoamine oxidase inhibitors; increasing
d. Monoamine oxidase inhibitors; decreasing
e. Monoamine oxidases; decreasing
Q:
Which of the following is correctly defined with regards to catecholamines?
a. reserpine increases brain monoamine levels by upregulation of vesicle production
b. bromocriptine is a dopamine antagonist linked to some Parkinson's disease indidences
c. cocaine binds to monoamine reuptake transporters on the presynaptic membrane thus prolonging the effects of monoamines
d. Prozac is a highly specific dopamine reuptake inhibitor
e. none of the above
Q:
All are catecholamine neurotransmitters EXCEPT:a. -aminobutyrate (GABA).b. L-dopa.c. dopamine.d. epinephrine.e. norepinepherine.
Q:
The effects of ethanol on the brain arise in part from opening of ____ receptor Cl-channels.a. glycineb. aspartatec. glutamated. -aminobutyrate (GABA)e. all are true
Q:
It is believed that many general anesthetics work by prolonging the open time of GABA receptors. What type of channel does the GABA receptor mediate?
a. sodium
b. calcium
c. chloride
d. potassium
e. all are true
Q:
Like acetylcholine, ____ and ____ are excitatory, but must be removed by ____.
a. Asp; Lys; degradation
b. Asp; Gly; reuptake
c. Glu; Gln; reuptake
d. Gln; Lys; degradation
e. Lys; Arg; degradation
Q:
Characteristics of myasthenia gravis include all EXCEPT:
a. chronic disorder causing muscle weakness.
b. autoimmune disease.
c. individual's antibodies bind their own acetylcholinesterase receptors.
d. physiostigmine and neostigmine are used to treat myasthenia gravis.
e. all are true.
Q:
Neurotransmitters must be removed from the synaptic cleft to:
a. promote prolonged stimulation of the postsynaptic cell.
b. prevent prolonged stimulation of the presynaptic cell.
c. promote prolonged stimulation of the presynaptic cell.
d. prevent prolonged stimulation of the postsynaptic cell.
e. none of the above.
Q:
All are inhibitors of acetylcholinesterase EXCEPT:
a. sarin.
b. malathion.
c. parathion.
d. tabun.
e. all are inhibitors.
Q:
Acetylcholinesterase:
a. catalyzes synthesis of acetylcholine.
b. is regulated by binding of cocaine.
c. hydrolyzes acetylcholine inside the presynaptic cell.
d. normally functions to prolong stimulation of the postsynaptic cell.
e. must be secreted into the synaptic cleft.
Q:
Botulism toxin inhibits the potentiation of nerve impulses by interfering with what aspect of acetylcholine signaling?
a. prevents calcium channel opening, thus preventing the influx of calcium needed to release acetylcholine
b. prevents acetylcholine vesicles from fusing with the presynaptic neuronal membrane
c. acts as an acetylcholinesterase to degrade acetylcholine in the synaptic cleft before it can bind to receptors on the postsynaptic neuron
d. binds to receptors on the postsynaptic neuron with very high affinity, preventing acetylcholine from binding
e. none of the above
Q:
During an action potential, which of the following is directly responsible for restoration of resting membrane potential?
a. efflux of K+ ions
b. efflux of Na+ ions
c. influx of K+ ions
d. influx of Na+ ions
e. efflux of Clï€ ions
Q:
Which of the following statements regarding neurons and the action potential is NOT true?
a. efflux of K+ ions leads to a brief hyperpolarization of the cell membrane
b. the resting membrane potential is approximately ï€80mV
c. sodium ions that enter an axon through sodium channels in a given axonal region diffuse further along the axon, depolarizing the next axonal region
d. in myelinated axons, sodium channels are distributed evenly
e. all of the above are true
Q:
In a neuron, when voltage-gated Na+channels have just closed, which of the following is true?
a. the membrane is less polarized than at rest
b. the membrane is more polarized than at rest
c. the membrane is polarized to the same degree as at rest
d. the membrane is hyperpolarized
e. none of the above are true
Q:
____ of Tyr527in the SH2 domain of protein tyrosine kinase ____ tyrosine kinase activity by moving an "activation loop" ____ the active site.a. Phosphorylation; activates; away fromb. Phosphorylation; inhibits; intoc. Dephosphorylation; inhibits; away fromd. Dephosphorylation; activates; intoe. none are true
Q:
The original phorbol esters are natural products that mimic ____ by binding and activating ____ that potentiate the effects of ____.
a. hormones; PKA; Ca2+
b. DAG; PKC; carcinogens
c. cAMP; PKA; glucagon
d. Ca2+; PKC; Ca2+
e. PIP2; CaM; Li+
Q:
The members of the protein kinase C family that are regulated by Ca++, by diacylglycerol and by phosphatidylserine are called the:
a. atypical PKCs.
b. conventional PKCs.
c. modified PKCs.
d. novel PKCs.
e. all of the above.
Q:
All are characteristic of EF-hand proteins EXCEPT:
a. EF-hand domains usually are arranged so that two EF-hand domains directly contact each other.
b. EF-hand proteins dramatically change conformation upon binding Ca++ ions.
c. Conformational changes promote binding of the EF-hand protein with its target protein(s).
d. CaM (a EF-hand protein) binds target protein with basic amphiphilic alpha helix (Baa helix) motifs.
e. All are characteristic.
Q:
Rapid influx of Ca++into the cytoplasm can occur as a result of the binding of hormones to a receptor activating phospholipase C activity. The increased level of Ca++is derived from all of the following EXCEPT:
a. lysozymes.
b. calciosomes.
c. endoplasmic reticulum.
d. extracellular stores through Ca++ channels in the plasma membrane.
e. all of the above.
Q:
Calcium binding proteins all possess two or more characteristic peptide domains for Ca++binding that consist of a short -helix, a loop of 12 amino acids and a second -helix (helix-loop-helix) that is called:a. basic region leucine zipper.b. zinc finger.c. EF hand.d. beta-beta.e. none are true.
Q:
Calmodulin exhibits all of the following characteristics EXCEPT:
a. its conformation is sensitive to Ca++ binding.
b. it contains a basic amphiphilic alpha helix which interacts with target proteins.
c. it modulates the activity of many protein kinases.
d. it contains one or more helix-loop-helix motifs (EF-hands) which bind the Ca++ ion.
e. all are characteristics.
Q:
Lithium salts have been used for years for the treatment of manic depression. Although its mechanism of action at the molecular level is far from clear, it has been shown that Li+:
a. alters the conformation of a number of plasma protein receptors.
b. increases the GTPase activity of G-proteins.
c. inhibits a number of enzymes in phosphoinositide metabolism.
d. inhibits Ca++ release from cytoplasmic organelles.
e. activates protein kinase A much like cAMP does.
Q:
All are results of the phospholipase C activity mediated by hormone binding, signal transduction and eventually Ca++release into the cytoplasm EXCEPT:
a. an increase in guanylyl cyclase activity.
b. the phosphorylation of specific proteins.
c. activation of protein kinases by calcium complexed with calmodulin.
d. the release of diacylglycerol from membrane phospholipids.
e. the release of IP3.
Q:
Transient increases in cytoplasmic Ca2+levels can activate all EXCEPT:
a. muscle contraction.
b. glucose uptake.
c. exocytosis.
d. glycogen metabolism.
e. all are true.
Q:
The phospholipid that is hydrolyzed to stimulate ceramide-activated protein kinase is:
a. sphingomyelin.
b. phosphatidylinositol-4,5-bisphosphate.
c. phosphatidylinositol-4-phosphate.
d. phosphatidylcholine.
e. phosphatidylinositol.
Q:
Phospholipase is activated by ____ while phospholipase is activated by ____.a. receptor tyrosine kinase; b. receptor tyrosine kinase; cAMPc. nitric oxide; d. protein kinase A; cAMPe. none of the above
Q:
Cancerous tumors may develop from all of the following EXCEPT:
a. mutations in several proto-oncogenes or tumor suppression genes.
b. interactions among two or more oncogene products.
c. simultaneous mutations in a proto-oncogene and both copies of a tumor suppression gene.
d. overlapping growth-control mechanisms that when one is compromised by mutation, others take over.
e. all are true.
Q:
The second messenger produced from the hydrolysis of PIP2that activates the increase of Ca++concentrations in the cytoplasm is:
a. diacylglycerol (DAG).
b. phosphatidylinositol (PI).
c. phosphatidylinositol-4,5-bisphosphate (PIP2).
d. inositol-1,4,5-trisphosphate (IP3).
e. inositol-1,4-bisphosphate (IP2).
Q:
The hydrolysis of PIP2by phospholipase C-yields what membrane-soluble secondary messenger?a. diacylglycerol (DAG)b. phosphatidylinositol (PI)c. phosphatidylinositol-4,5-bisphosphate (PIP2)d. inositol-1,4,5-trisphosphate (IP3)e. inositol-1,4-bisphosphate (IP2)
Q:
G-proteins are involved in directlymediating the activity of the following EXCEPT:a. calmodulin.b. adenylyl cyclase.c. phospholipase C-.d. phospholipase A2.e. ion channels for K+ and other ions.
Q:
Which of the following is a result of the sumoylation of a protein?
a. addition of SUMO targets a protein for destruction by a slightly different pathway than attachment of ubiquitin
b. addition of SUMO often changes the conformation of a protein so that it interacts with other proteins in a different manner
c. addition of SUMO targets a protein for transport into the mitochondria
d. the addition of SUMO occurs during the translation process and is meant to stall translation of certain proteins
e. none of the above
Q:
Which of the following proteins would be commonly ubiquitinated and thus degraded by the proteasome?
a. proteins with Met as the N-terminal amino acid
b. proteins with short sequences rich in Pro, Glu, Ser and Thr
c. proteins with short sequences rich in Trp, Thr, and Phe
d. proteins having a C-terminal Cys for the formation of a thioester bond with ubiquitin
e. none of the above
Q:
What does Hsp (as in Hsp60) stand for?
a. helical stabilizing protein
b. hydrophobic sequestering protein
c. heat shock protein
d. high-histidine subunit protein
e. none of the above
Q:
All are characteristics of HtrA proteases EXCEPT:
a. ATP-dependent.
b. chaperones at low temperatures.
c. proteases at high temperatures.
d. bind misfolded or unfolded proteins.
e. all are true.
Q:
In the proteosomes, the 19S cap acts as a ____ complex for the recognition and selection of ____ proteins for ____ by the 20S proteosomes core.
a. hydrolysis; unfolded; disposal
b. regulatory; unfolded; disposal
c. hydrolysis; ubiquitinylated; degradation
d. regulatory; ubiquitinylated; degradation
e. all are true
Q:
In a protein targeted for destruction, ubiquitin is most commonly attached to a _____ residue, forming a/an ______ bond between ubiquitin and the targeted protein.a. Ser; esterb. Lys; amidec. -amine group of the N-terminal amino acid if the particular residue is Arg, Lys, His, Phe, Tyr, Trp, Leu, Asn, Gln, Asp or Glu; amided. Glu; acid anhydridee. Cys; thioester
Q:
The appropriate sequence for ubiquitination of proteins to be degraded is:
A. multiple ubiquitinations may occur on a protein substrate,
B. ubiquitin-protein ligase (E3) transfers ubiquitin to free amino groups on the protein,
C. E3 selects a protein for degradation by the nature of the N-terminal amino acid,
D. ubiquitin-carrier protein (E2) picks up ubiquitin,
E. ubiquitin-activating enzyme (E1) attaches via ATP-dependent formation of thioester bond to C-termini of ubiquitin,
a. A, C, B, D, E
b. E, D, A, B, C
c. D, E, C, A, B
d. C, E, D, B, A
e. E, D, C, B, A
Q:
All are correct statements regarding the protein degradation process involving ubiquitin EXCEPT:
a. The modified protein is degraded by an ATP-dependent protease complex.
b. The ubiquitin binding to the protein to be degraded leads to a novel branched protein.
c. The ubiquitin is covalently attached to a cysteine residue in the protein to be degraded.
d. Three additional proteins (E1, E2, and E3) are involved in the ligation of ubiquitin to the protein.
e. Ubiquitin is a highly conserved protein.
Q:
A highly conserved protein that is involved in protein degradation is:
a. ricin
b. met-aminopeptidase
c. ubiquitin
d. degradase
e. peptidyl transferase
Q:
Protein degradation is compartmentalized either in macromolecular structures known as ____ or in degradative organelles such as ____.
a. ribosomes; endoplasmic reticulum
b. ribosomes; Golgi
c. proteosomes; mitochondria
d. proteosomes; lysosomes
e. lysosomes; endoplasmic reticulum
Q:
The proper sequence for transport of mitochondrial matrix proteins would be:
a. TOM; TIM22
b. TOM; TIM23
c. SAM; TOM; TIM22
d. TOM; SAM; TIM22
e. SAM; TOM; TIM23
Q:
Mitochondrial presequences are ____ charged amphipathic sequences retained in the ____ stage through association with ____ molecular chaperones.
a. positively; folded; Hsp40
b. positively; unfolded; Hsp70
c. negatively; folded; Hsp70
d. neutral; unfolded; Hsp40
e. negatively; prefolded; Hsp90
Q:
Proteins with ____ sequences remain embedded in the ER membrane with their ____-termini on the cytosolic face of the ER.
a. translocator; N
b. leader; C
c. translocational; N
d. stop-transfer; C
e. translocon; N
Q:
Characteristics of the mammalian translocon include all EXCEPT:
a. sec61 complex at the core.
b. transmembrane protein-conducting channel.
c. BiP carries out ATP-dependent protein folding.
d. composed of a single transmembrane spanning (TMS) protein.
e. all are true.