CBE2 Combined

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What is the refractive index of water?

1.33

In a Lineweaver-Burk plot of the dependence of enzyme velocity on substrate concentration, what is the value of the function at X=0 (i.e., the Y-intercept)?

1/Vmax

During transport through the V-type ATP-dependent proton pump, how many protons are transported per ATP hydrolyzed?

4 protons pumped per ATP hydrolyzed

How many protein molecules are incorporated into a clathrin triskelion complex?

how many protein molecules are incorporated into a clathrin triskelion complex?

6 - clathrin cage (no vesicle) - a minimum of 36 clathrin triskelions are required to form a closed structure - are formed by 3 heavy and 3 light chains

Which of the following sorting signals marks a soluble protein for transport to the nucleus?

- PPKKKRKL-

The Get3 ATPase facilitates the post-translational insertion of certain proteins into the ER membrane. Which of the following is the common feature of proteins that rely on the Get3 ATPase for insertion into the ER membrane?

A single transmembrane domain at the C-terminus

During the IRE1 Unfolded Protein Response, the ribonuclease domain on the cytosolic side of the activated IRE1 receptor excises an intron from a pre-mRNA molecule in the cytosol. The resultant mRNA molecule encodes which of the following?

A transcription factor

Which of the following is not one of the three pathways to degradation in the lysosome? A. M6P pathway B. endocytosis C. phagocytosis D. autophagosome

A. M6P pathway

Which of the following is the ATPase that unravels the SNARE complex? A. NSF B. SAR1 C. dynamin D. RABs E. SNAP25

A. NSF

Which of the following C-term sequences could identify proteins for return from the cis-Golgi? A. NYLSCKDEL B. APPRRRKRV C. MLAVALVIA D. LRNSIRFFLK E. GATALACAT

A. NYLSCKDEL

Most proteins destined to enter the ER... A. are transported across the membrane after their synthesis is complete B. are synthesized on free ribosomes in the cytosol C. begin to cross the membrane while still being synthesized D. remain within the ER E. must first pass through the endosomal system before returning to the ER

C. begin to cross the membrane while still being synthesized

During co-translational transport, which of the following events interrupts translation of the nascent polypeptide? A. emergence of the ER signal sequence from the ribosome B. binding of the SRP to the ER signal sequence on the nascent polypeptide C. binding of the SRP near the "A" site of the ribosome D. binding of the SRP to the SRP receptor E. binding of the ER signal sequence to the stop-transfer site on the translocation

C. binding of the SRP near the "A" site of the ribosome

Which of the following best describes the events that occur after photoisomerization of 11-cis retinal in rod cells? A. cGMP levels increase, Na+ channels open, cell depolarizes, glutamate release increases B. cGMP levels decrease, Na+ channels close, cell depolarizes, glutamate release increases C. cGMP levels decrease, Na+ channels close, cell hyperpolarizes, glutamate release decrease D. cGMP levels increase, Na+ channels close, cell depolarizes, glutamate release increases

C. cGMP levels decrease, Na+ channels close, cell hyperpolarizes, glutamate release decrease

Which vesicle type contains proteins destined for the lysosome? A. COP1-coated B. COP11-coated C. clathrin-coated D. retromer E. caviolin

C. clathrin-coated

Receptor-mediated endocytosis involves which of the following coated vesicles? A. COP1 vesicles B. retromer vesicles C. clathrin-coated vesicles D. caveoli E. multivesicular bodies

C. clathrin-coated vesicles

Mis-folded proteins that escape degradation are sorted to which compartment? A. Golgi B. lysosome C. constitutive secretory vesicles D. endosomes E. multivesicular bodies

C. constitutive secretory vesicles

Clathrin-coated vesicles transport proteins to which of the following target compartments? A. plasma membrane B. ER C. endosomes D. cis-Golgi E. all of the above

C. endosomes

Posttranslational transport of proteins in to the peroxisome is unusual, in that these proteins are... A. de-phosphorylated B. deglycosylated C. folded D. unfolded E. none of the above

C. folded

Nitric oxide directly activates which of the following target proteins? A. PKA B. CREB C. guanylyl cyclase D. cGMP phosphodiesterase E. adenylyl cyclase

C. guanylyl cyclase

Which of the following proteins is directly activated by nitric oxide? A. nitric oxide receptor B. acetylcholine receptor C. guanylyl cyclase D. adenylyl cyclase E. phosphodiesterase

C. guanylyl cyclase

Activation of phospholipase C-beta results in the production of two-signaling molecules. Which signaling molecule is responsible for the release of calcium from the smooth ER? A. inositol 3,4,5 triphosphate B. inositol 2,4,5 triphosphate C. inositol 1,4,5 triphosphate D. diacylglycerol E. none of the above

C. inositol 1,4,5 triphosphate

Ach opens potassium channels on cardiac myocytes through activation of the beta-gamma complex. Which of the following best describes the Ach receptor that mediates this effect? A. second messenger-gated ion channel B. nuclear receptor C. metabotropic Ach receptor D. ionotropic Ach receptor E. ligand-gated ion channel

C. metabotropic Ach receptor

Which of the following extracellular messengers acts as a paracrine signal? A. testosterone B. acetylcholine C. nitric oxide D. cyclic AMP E. all of the above

C. nitric oxide

Which of the following signaling enzymes creates sites on the plasma membrane for the recruitment and activation of protein kinase C? A. adenylyl cyclase B. guanylyl cyclase C. phospholipase C D. PI3 kinase E. GRK kinase

C. phospholipase C

What do ESCRT protein complexes do? A. they are transcription factors B. they escort proteins across the plasma membrane C. they form intraluminal vesicles in endosomes D. they regulate calcium efflux from the smooth ER E. none of the above

C. they form intraluminal vesicles in endosomes

Which of the following best describes the orientation of a protein in the ER membrane that contains a N-term ER signal sequence and three internal hydrophobic domains? A. four transmembrane alpha helices with N-term in the ER lumen B. four transmembrane alpha helices with N-term in the cytoplasm C. three transmembrane alpha helices with N-term in the ER lumen D. three transmembrane alpha helices with N-term in the cytoplasm E. three transmembrane alpha helices with N-term and C-term on the same side of the ER membrane

C. three transmembrane alpha helices with N-term in the ER lumen

Which process is responsible for the delivery of antibodies across the intestinal epithelium of a newborn? A. pinocytosis B. phagocytosis C. transcytosis D. endocytosis E. basolaterosis

C. transcytosis

Which of the following best describes the orientation of a protein in the ER membrane that contains N-term ER localization signal and 2 internal hydrophobic domains? A. three transmembrane alpha helices with N-term in the cytosol B. three transmembrane alpha helices with N-term in the ER lumen C. two transmembrane alpha helices with N-term in the ER lumen D. two transmembrane alpha helices with C-term in the cytosol E. two transmembrane alpha helices with N-term and C-term on opposite sides of the ER

C. two transmembrane alpha helices with N-term in the ER lumen

In addition to displaying a mitochondrial signal sequence, proteins entering the mitochondria must be... A. phosphorylated B. glycosylated C. unfolded D. misfolded E. none of the above

C. unfolded

occupied KDEL receptors are loaded into which of the following vesicles?

COP1 - copI and copII vesicles carry between the ER and the golgi complex -returned to ER via COPI (retrieval) -Bidirectional transport between cisternae of the golgi complex occurs through transport vesicle copI -C terminal KDEL marks ER resident proteins -soluble ER resident proteins display the C-terminal KDEL sequence which binds to KDEL receptors in the vesicular tubular cluster and golgi complex

Complete the following sentence. "In the Golgi complex, ER resident proteins are returned to the ER membrane in ..."

COP1 vesicles

Occupied KDEL receptors are loaded into which of the following vesicles

COP1 vesicles

What is the energy source that drives chromosomal segregation during anaphase B?

ATP hydrolysis

Which of the following events "cocks" the neck linker on myosin II motor proteins?

ATP hydrolysis

Which of the following describes a molecule the mimics the effect of a natural ligand by binding to its cognate receptors?

Agonist

Which of the following describes an agent that mimics the effect of ligand by binding to its cognate receptor?

Agonist

The effect of cholera toxin treatment on trimeric G-protein signaling is due to which of the following covalent modifications? A. ubiquination of the alpha subunit B. ADP ribosylation of the alpha subunit C. phosphorylation of the beta-gamma complex D. phosphorylation of the alpha subunit E. dephosphorylation of the beta gamma complex

B. ADP ribosylation of the alpha subunit

Which of the following signal sequences could direct proteins to the nuclear compartment? A. NYLSCKDEL B. APPRRRKRV C. MLAVALVIA D. LRNSIRFFLK E. GATALACAT

B. APPRRRKRV

ER resident proteins in the Golgi complex are returned to the ER via which of the following? A. clathrin vesicles B. COP1 vesicles C. COP11 vesicles D. retromers E. post-translational transport

B. COP1 vesicles

Proteins expressing a C-term KDEL sequence are returned to the ER in which of the following? A. clathrin-coated vesicles B. COP1 vesicles C. COP11 vesicles D. in caveoli E. diffusion through the cytosol

B. COP1 vesicles

Which of the following coat proteins are responsible for the formation of secretory vesicles at the Golgi complex? A. COP1 proteins B. COPII proteins C. Clathrin D. retromer proteins E. caviolin

B. COPII proteins

Which of the following coat proteins are responsible for the formation of transport vesicles at the ER membrane? A. COP1 proteins B. COPII proteins C. Clathrin D. retromer proteins E. caviolin

B. COPII proteins

You have generated antibodies that recognize the extracellular domain of the Ca2+ pump. Adding these antibodies to animal cells blocks the active transport of Ca2+ from the cytosol into the extracellular environment. What do you expect to observe with respect to intracellular Ca2+? A. Ca2+ pumps in vesicles membranes keep cystosolic calcium levels low B. Ca2+ pumps in the ER membrane keep cystosolic calcium levels low C. Ca2+ pumps in the Golgi apparatus keep cystosolic calcium levels low D. Ca2+ concentrations in the cytosol increase at a steady rate. E. all of the above

B. Ca2+ pumps in the ER membrane keep cystosolic calcium levels low

During delta-notch signaling, what message does the delta ligand convey to cells expressing the notch receptor? A. Become a neuron B. Don't become a neuron C. Don't become a neuroglia D. Just don't

B. Don't become a neuron

In which of the following compartments would you expect to find a protein that displays the C-terminal sequence -Lys-Asp-Glu-Leu? A. cytoplasm B. ER C. lysosomes D. peroxisomes E. this sequence only makes sense when it is present at the N-term of the protein

B. ER

The IRE1 unfolded protein response pathway results in biosynthesis of which of the following proteins? A. ribsosomal proteins B. ER chaperone proteins C. SEC61 D. nuclear import receptors E. none of the above

B. ER chaperone proteins

Only properly folded proteins that display the mitochondrial sorting sequence can enter the mitochondrial matrix via the TOM-TIM23 complex. A. True B. False

B. False

When an unknown peptide is added to cultured epithelial cells, it results in the accumulation of cyclic AMP in the cytoplasm. This effect is blocked by pertussis toxin but NOT by cholera toxin. Which of the following G-proteins is most likely responsible for the unknown peptide signaling in epithelial cells? A. Gs B. Gi C. Go D. Gq E. Gt

B. Gi

An extracellular messenger molecule that increases intracellular calcium levels in target cells, and is NOT blocked by pertussis toxin, is mostly likely signaling through? A. Go B. Gq C. Gs D. Gi E. Gt

B. Gq

What is the function of the synaptic protein, synaptotagmin? A. It is the T-SNARE on the synaptic plasma membrane B. It is the calcium sensor protein on the synaptic vesicle C. It is the V-SNARE on the synaptic vesicle D. It is the V-type ATPase on the synaptic vesicle

B. It is the calcium sensor protein on the synaptic vesicle

Which of the following signal sequences identifies proteins for transport to the peroxisomes? A. KDEL B. SKL C. BIP D. M6P E. OXA

B. SKL

The ER resident chaperone, calnexin, identifies potentially mis-folded proteins by binding to which of the following? A. the ER signal sequence B. the terminal glucose residue on the oligosaccharide C. the terminal mannose residue on the oligosaccharide D. the mannose-6-phosphate moiety E. the glucose-6-phosphate moiety

B. the terminal glucose residue on the oligosaccharide

Activation of the unfolded protein responses via the IRE1 mechanism results in the accumulation in the ER lumen of which of the following proteins?

BIP

activation of the unfolded protein response via the IRE1 mechanism results in the accumulation in the ER lumen of which of the following proteins?

BIP 1. ER chaperones (BIP) assist in folding of soluble proteins in the ER lumen 2. properly folded proteins are recognized by cargo receptors on budding transport vesicles 3. only properly folded proteins get out once the proteins are synthesized they must rapidly fold into an active conformation

Which of the following proteins is/are an ABC transporter(s)?

Bacterial permeases Cystic fibrosis transmembrane conductance regulator Multidrug resistance proteins

Which of the following are the essential characteristics of all living cells?

Bound by a lipid-rich plasma membrane Contains nucleic acid that encodes at least one copy of the genome Capable of autonomous replication Capable of protein synthesis

Which of the following amino acid sequences identifies a soluble protein for retention in the ER? A. -Pro-Pro-Lys-Lys-Arg-Lys-Lys-Val- B. -Ser-Lys-Leu-COOH C. -Lys-Asp-Glu-Leu-COOH D. -Met-Met-Leu-Leu-Leu-Val-Gly-Ile-Leu-Phe-Trp-Ala-Thr-Glu

C. -Lys-Asp-Glu-Leu-COOH

How many sugar moieties are added to the dolichol-bound precursor oligonucleotide in the cytoplasm? A. 2 B. 5 C. 7 D. 10 E. 14

C. 7

Which of the following ligands does not signal through intracellular receptors? A. thyroxine B. vitamin D3 C. GH D. cortisol E. all of the above signal through intracellular receptors

C. GH

During receptor-mediated endocytosis, which of the following events releases clathrin-coated vesicles from the plasma membrane? A. phosphorylation of clathrin B. dephosphorylation of clathrin C. GTP hydrolysis by the dynamin complex D. GTP hydrolysis by the RAB GTPase E. dissociation of the clathrin coat

C. GTP hydrolysis by the dynamin complex

Activation of a novel GPCR increases phospholipase C activity, and this effect is blocked by pertussis toxin. This GPCR is probably signaling through which of the following G-protiens? A. Gs B. Gi C. Go D. Gq E. Ras

C. Go

Which of the above N-term sequences could direct a secretory protein to the ER membrane for co-translational transport? A. NYLSCKDEL B. APPRRRKRV C. MLAVALVIA D. LRNSIRFFLK E. GATALACAT

C. MLAVALVIA

Nuclear import receptors release their cargo proteins in the nuclear compartment because... A. the GTP concentration in the nucleus is very low B. the calcium concentration in the nucleus is very high C. RAN-GTP binding reduces the affinity of NPRs for cargo proteins D. RAN-GDP binding reduces the affinity of NPRs for cargo proteins E. RAN-GEF binding reduces the affinity of NPRs for cargo proteins

C. RAN-GTP binding reduces the affinity of NPRs for cargo proteins

During transport of proteins into the mitochondrion, what is the role of the SAM complex? A. SAM transports only those proteins encoded by mitochondrial DNA B. SAM chaperones assist in protein folding in the mitochondrial matrix C. SAM supports the insertion of integral membrane proteins into the other mitochondrial membrane D. SAM supports the insertion of integral membrane proteins into the other mitochondrial membrane E. none of the above

C. SAM supports the insertion of integral membrane proteins into the other mitochondrial membrane

A ligand-bound GPCR behaves like which of the following? A. a protein kinase B. a protein phosphatase C. a guanine nucleotide exchange factor D. a GTPase activating factor E. a nuclear localization signal

C. a guanine nucleotide exchange factor

In the trans-Golgi network, pro-enzyme hydrolases destined for late endosomes are identified by which of the following features? A. an endosomal signal sequence B. a specific pattern of phosphorylation C. a mannose-6-phosphate moiety on the oligosaccharide D. covalent lipid tags

C. a mannose-6-phosphate moiety on the oligosaccharide

Which of the following is false about the N-glycosylation process? A. it begins in the ER lumen B. a preformed oligosaccharide is attached to the amide nitrogen of a asparagine residue C. a preformed oligosaccharide is attached to the N-term amino acid residue D. the last two glucose residues are eventually cleaved E. all of the above are false

C. a preformed oligosaccharide is attached to the N-term amino acid residue

Mannose-6-phosphate tags are created in the Golgi complex to identify which of the following enzymes for delivery to endosomes A. ESCRT proteins B. clathrin C. acid hydrolases D. V-type ATPases

C. acid hydrolases

Which of the following bests describes the orientation of an ER membrane protein containing an N-terminal ER import signal sequence and three additional runs of 18 small non-polar amino acids? A. Four transmembrane domains with the carboxyl terminal in the ER lumen B. Four transmembrane domains with the carboxyl terminal in the cytosol C. Three transmembrane domains with the carboxyl terminal in the ER lumen D. Three transmembrane domains with the amino and carboxyl terminals on the same side of the membrane E. Three transmembrane domains with the amino and carboxyl terminals on opposite sides of the membrane

E. Three transmembrane domains with the amino and carboxyl terminals on opposite sides of the membrane

COP1 vesicles transport ER resident proteins from which of the following compartments? A. golgi cisternae B. trans golgi network C. vesicular-tubular cluster D. cis golgi network E. all of the above

E. all of the above

The specificity of which of the following cell signaling mechanism is primarily dependent upon the availability of specific receptors on the target cell. A. endocrine signaling B. synaptic transmission C. contact-dependent signaling D. paracrine signaling E. all of the above

E. all of the above

Which of the following contains material destined for delivery to the lysosome? A. multivesicular bodies B. autophagosomes C. phagosomes D. late endosomes E. all of the above

E. all of the above

Which of the following is not required for transport into the mitchondrial matrix? A. an N-term mitochondrial signal sequence B. ATP hydrolysis during transport across the outer mitochondrial membrane C. ATP hydrolysis during transport across the inner mitochondrial membrane D. the electrochemical gradient across the inner mitochondrial membrane E. all of the above

E. all of the above

Which of the following is true regarding the role of Rab GTPase in vesicular transport? A. it becomes associated with the source membrane prior to vesicle formation B. it identifies the target compartment of the vesicle C. it directs the transport machinery to deliver the vesicle to the target compartment D. it binds to tethering proteins on the surface of the target compartment E. all of the above are true

E. all of the above are true

During translation of a protein bound for the ER, a signal recognition particle (SRP) binds to the ER signal sequence, and translation is arrested. When does translation of this protein resume? A. dissociation of the SRP B. phosphorylation of the SRP C. assembly of the ribosome D. binding of the complex to the SRP receptor E. binding of the ribosome to the ER translocator proteinN

E. binding of the ribosome to the ER translocator protein

Photoisomerization of 11-cis retinal activates rhodopsin, which, in turn, activates the trimeric G-protein, Gt. Which of the following membrane associated enzymes is activated by Gt? A. adenylyl cyclase B. guanylyl cyclase C. phospholipase C-beta D. cAMP PDE E. cGMP PDE

E. cGMP PDE

During vesicle formation, adaptins bind FIRST to which of the following proteins? A. other adaptins B. adaptin receptors C. clathrin D. RAB E. cargo receptors

E. cargo receptors

Which small GTPase is responsible for the release of clathrin-coated vesicles from the plasma membrane? A. Ran B. Rab C. Ras D. Rob E. dynamin

E. dynamin

Nicotine is one of the most addictive substances known. How does nicotine exert its physiological effects in humans? A. it stimulates the release of Ach from cholinergic nerve terminals B. it blocks the synthesis of Ach in cholinergic nerve terminals C. it inhibits the degradation of Ach at cholinergic synapses D. it acts as an antagonist on Ach receptors E. it acts as an agonist on Ach receptors

E. it acts as an agonist on Ach receptors

Mitochondrial proteins encoded by the nuclear genome are transported into the mitochondrion only when they ... A. include an N-terminal mitochondrial signal sequence B. are unfolded C. are bound to a transport receptor on the outer mitochondrial membrane D. are accompanied by chaperone proteins E. satisfy all of the criteria above

E. satisfy all of the criteria above

During ubiquitin-mediated proteolysis, which subunit of the ubiquitin ligase complex transfers a ubiquitin molecule to the epsilon amino group of a lysine residue on the target protein?

E2 subunit

During ubiquitin-mediated proteolysis, which subunit of the ubiquitin ligase complex binds to the target protein?

Is the following statement TRUE of FALSE? "No molecule can traverse the nuclear pore complex without the assistance of a nuclear transport receptor".

FALSE

Which of the following is a method for the quantitative measurement of the rate of lateral diffusion of membrane proteins and lipids?

FRAP

Is the following statement True or False? Protein kinases always activate their substrate phosphoproteins.

False

No molecule can traverse the nuclear pore complex without the assistance of a nuclear transport receptor

False

Protein kinases always activate their substrate phosphoproteins

False

Which of the following is the largest family of cell signaling proteins encoded in the human genome?

G-protein coupled receptor

Which of the following is the largest family of cell signaling proteins encoded in the human genome?

G-protein coupled receptors

at which phase of the cell cycle do the SMC protein complexes that prevent premature separation of sister chromatids first assemble around DNA

G1 Phase

Which of the following Cdk complex cyclin matches is correct

G1/S-cdk & cyclin E S-cdk & cyclin A M-cdk & cyclin B

Which of the following statement regarding HSP70-type molecular chaperones is true?

GTP hydrolysis results in the binding of chaperone proteins to polar amino acids on the targets protein

In epithelial cell, how is glucose transported across the basolateral membrane?

Glucose uniporter

Which of the following is True regarding bacteriorhodopsin?

It is a light-activat4ed proton pump it has seven transmembrane alpha helices it includes a covalently-bound retinal cofactor

Which of the following amino acid sequences identifies a soluble protein for nuclear import? A. -Pro-Pro-Lys-Leu-Lys-Arg-Lys-Val B. -Pro-Pro-Lys-Leu-Lys-Ala-Lys-Val C. -Pro-Pro-Lys-Lys-Lys-Ala-Lys-Val D. -Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val E. none of the above

D. -Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val

Calcium homeostasis is maintained, in part, through the action of calcium ATPase. The P-type pumps can be found on which of the following membranes? A. plasma membrane B. mitchondrial inner membrane C. smooth ER D. 2 of the above E. none of the above

D. 2 of the above A. plasma membrane C. smooth ER

How is vesicular fusion powered? A. GTP hydrolysis drives the formation of SNARE complexes B. ATP hydrolysis drives the formation of SNARE complexes C. GTP hydrolysis drives the dissociation of SNARE complexes D. ATP hydrolysis drives the dissociation of SNARE complexes E. none of the above

D. ATP hydrolysis drives the dissociation of SNARE complexes

What kind of proteins usually display this sequence? -Lys-Asp-Glu-Leu-COOH A. integral membrane proteins B. COP11 coat proteins C. secretory proteins D. ER resident proteins E. none of the above

D. ER resident proteins

Which of the following choices reflects the appropriate order through which a protein destined for the plasma membrane travels? A. lysosome to endosome to plasma membrane B. ER to lysosome to plasma membrane C. Golgi to endosome to plasma membrane D. ER to Golgi to plasma membrane E. depends on the protein

D. ER to Golgi to plasma membrane

What is the source of energy required to transport large proteins through nuclear pore complexes? A. Ca2+ gradient across the nuclear envelope B. proton gradient across the nuclear envelope C. ATP hydrolysis D. GTP hydrolysis E. no energy is required

D. GTP hydrolysis

During cell signaling through G-protein coupled receptors, what event enables binding of the alpha subunit to the beta-gamma subunit? A. exchange of bound GDP for GTP on the alpha subunit B. exchange of bound GDP to GTP on the beta-gamma subunit C. GTP hydrolysis by the beta-gamma complex D. GTP hydrolysis by the alpha subunit E. dephosphorylation of the alpha subunit

D. GTP hydrolysis by the alpha subunit

A new drug increases the secretion of a hormone through activation of a GPCR. Pre-treatment of the cells with cholera toxin increases the magnitude and duration of the response of the drug. This observation suggests that the drug is probably signaling through which of the following trimeric G-proteins? A. Gq B. Gt C. Gi D. Gs E. Go

D. Gs

During vesicle formation at the plasma membrane clathrin triskelions bind to which of the following proteins? A. cargo proteins B. cargo receptors C. adaptin receptors D. adaptins

D. adaptins

Which of the following protein families is NOT involved in directing transport vesicles to the target membrane? A. SNARES B. Rabs C. tethering proteins D. adaptins

D. adaptins

The energy required for transport of cytoplasmic proteins into the mitochondrial matrix is provided by which of the following? A. ATP hydrolysis in the cytoplasm B. ATP hydrolysis in the matrix C. the proton electrochemical gradient across the inner membrane D. all of the above

D. all of the above

Which of the following is/are true regarding the IRE1 unfolded protein response? A. it is triggered by the accumulation of mis-folded proteins in the ER B. it involves activation of a latent ribonuclease C. it promotes the biosynthesis of ER chaperone proteins D. all of the above are true E. all of the above are false

D. all of the above are true

Nitric oxide is enzymatically produced by nitric oxide synthase, what is the substrate for this reaction? A. nitrate ion B. ammonia C. lysine D. arginine E. asparagine

D. arginine

Dissociation of the cargo protein from the nuclear import receptor is caused by which of the following? A. the low pH of the nuclear compartment B. the high calcium concentration within the nuclear compartment C. mass action D. binding of RAN-GTP E. dissociation of RAN-GTP

D. binding of RAN-GTP

Calcium-calmodulin-dependent protein kinase II (CaMK) is fully activated by... A. binding of calcium-calmodulin B. autophosphorylation C. dephosphorylation D. binding of calcium-calmodulin AND autophosphorylation E. binding of calcium-calmodulin AND dephosphorylation

D. binding of calcium-calmodulin AND autophosphorylation

How does PKA activate gene expression? A. by phosphorylating CREB binding protein B. by phosphorylating RNA polymerase C. by phosphorylating CREB protein in the cytoplasm D. by phosphorylating CREB protein in the nucleus

D. by phosphorylating CREB protein in the nucleus

In rod photoreceptors, light-activation rhodopsin signals through the trimeric G-protein "transducin" resulting in the activation of which of the following enzymes? A. adenylyl cyclase B. guanylyl cyclase C. cAMP PDE D. cGMP PDE e. pka

D. cGMP PDE

Activation of rhodopsin by photoisomerization of 11 cis retinol causes which of the following outcomes? A. increase cGMP levels, membrane depolarization B. decrease cGMP levels, membrane depolarization C. increase cGMP levels, membrane hyperpolarization D. decrease cGMP levels, membrane hyperpolarization E. increase cAMP levels, membrane hyperpolarization

D. decrease cGMP levels, membrane hyperpolarization

During pinocytosis, EC fluid is delivered to which of the following compartments? A. lysosomes B. Golgi C. cytoplasm D. endosomes E. all of the above

D. endosomes

Phosphoisomerization of 11-cis retinal bound to rhodopsin results in which of the following? A. exchange of ATP for ADP-bound Gs and activation of adenylyl cyclase B. exchange of GTP for GDP-bound Gs and activation of adenylyl cyclase C. exchange of GTP for GDP-bound Gs and activation of PDE D. exchange of GTP for GDP-bound Gt and activation of PDE E. exchange of GTP for GDP-bound Gt and inhibition of guanylyl cyclase

D. exchange of GTP for GDP-bound Gt and activation of PDE

Viagara was discovered while searching for drugs that A. are effective treatment for ED B. increase libido C. increase blood pressure D. inhibit cyclic GMP PDE E. inhibit NO synthase

D. inhibit cyclic GMP PDE

Which of the following is false about the paracrine messenger nitric oxide? A. it is enzymatically produced from arginine B. it is produced in the endothelial cells C. it crosses cell membranes by simple diffusion D. it activates an adenylyl cyclase

D. it activates an adenylyl cyclase

If lysosomal enzymes leaked into the cytosol, cytoplasmic macromolecules would be protected from hydrolysis. Why? A. specific inhibitors of lysosomal enzymes are present in the cytosol B. lysosomal enzymes are inactive at cytoplasmic pH C. lysosomal enzymes require high calcium concentrations D. lysosomal enzymes require proteolytic activation E. all of the above are true

D. lysosomal enzymes require proteolytic activation

During ensosomal maturation, there is a gradual decline in which of the following characteristics? A. size of the endosome B. density of the endosome C. calcium concentration of the endosome D. pH of the endosome

D. pH of the endosome

Maturation of secretory proteins is completed in which of the following compartments? A. ER lumen B. cis-Golgi C. trans-Golgi D. secretory vesicle E. early endosome

D. secretory vesicle

What are nuclear receptors? A. proteins that bind to nuclear import signals and transport proteins across nuclear envelope B. cell surface receptors that are occasionally transported to the nucleus C. ER proteins that initiate the mis-folded protein response D. soluble, intracellular receptors of small lipid soluble messengers

D. soluble, intracellular receptors of small lipid soluble messengers

N-linked oligosaccharides on secreted glycoproteins are attached to... A. nitrogen atoms in the polypeptide backbone B. the serine or threonine in the sequence Asn-X-Ser/Thr C. the N-terminus of the protein D. the asparagine residue in the sequence Asn-X-Ser/Thr E. none of the above

D. the asparagine residue in the sequence Asn-X-Ser/Thr

Which of the following is responsible for directionality of transport of proteins into and out of the nucleus? A. the net charge of the flanking amino acids B. the GTP concentration gradient C. the RAN concentration gradient D. the restriction of RAN-GAP and RAN-GEF to opposite sides of the nuclear envelope E. all of the above

D. the restriction of RAN-GAP and RAN-GEF to opposite sides of the nuclear envelope

Which process is responsible for the delivery of antibodies across the intestinal epithelium of a newborn? A. pinocytosis B. phagocytosis C. endocytosis D. transcytosis E. basolaterosis

D. transcytosis

In late endosomes, which of the following covalent modifications marks a membrane receptor for incorporation into intralumenal vesicles A. phosphorylation of tyrosine residues B. proteolysis to reveal an ESCRT signal sequence C. phosphorylation of a mannose residues D. ubiquination of lysine residues

D. ubiquination of lysine residues

During early development of the vertebrate central nervous system, undifferentiated epithelial cells that enter the neuronal linage signal to their neighbors by displaying which pf the following membrane proteins?

Delta

Which of the following is not an ER resident protein? A. BIP B. calreticulin C. Sec61 D. IRE1 E. Hsp70

E. Hsp70

RAS-GTPase participates in which of the following signaling pathways? A. mTOR pathway B. IP3 pathway C. JAK kinase pathway D. phospholipase C-beta E. MAP kinase pathway

E. MAP kinase pathway

Inhibitory neurotransmitters like GABA hyperpolarize postsynaptic neurons by activating which of the following ion channels?

Ligand gated chloride channels

What are Caspases?

Proteases that cleave substrate at specific aspartate residues

Which of the following statement about microtubules are true

Most are composed of 13 protofilaments They are polymers of alpha-beta tubulin dimers They polymerize at the plus (+) ends

Which of the following is True regarding the N-glycosylation process?

N-glycosylation begins in the ER A preformed 14 residue oligosaccharide is transferred to the amide nitrogen of an asparagine on the glycoprotein the first 7 sugar residues of the oligosaccharide are attached to the dolichol carrier o the cytoplasmic side of the ER membrane The last three residues must be moved prior to incorporation of the glycoprotein into COP@ vesicles

N-glycosylation process?

N-glycosylation begins in the ER lumen b) A preformed, 14 residue oligosaccharide is transferred to the amide nitrogen of an asparagine residue on the glycoprotein c) The first 7 sugar residues of the oligosaccharide are attached to the dolichol carrier on the cytosolic side of the ER membrane d) The last three (glucose) residues of the oligosaccharide must be removed prior to incorporation of the glycoprotein into COP2 vesicles

Which of the following are intermediate filament proteins that are expressed in all eukaryotic cells?

Nuclear lamins

Which of the following is a function of the Golgi Complex?

O-Type glycosylation of protein Packaging and distribution of proteins Production of secretory vesicles

During S-phase, which of the following is phosphorylated by S-cdk complex to prevent a second round of DNA synthesis?

ORC

Prior to synaptic vesicle fusion, where would you be most likely to find the calcium sensor, synaptotagmin?

On the synaptic vesicle

Which of the following events is responsible for the depolarization phase of the action potential?

Opening of the voltage gated sodium channels

During receptor mediated endocytosis of LDL particles, what happens to the LDL receptor?

It is usually returned to the plasma membrane

Prolactin and some cytokines alter gene expression through which of the following signal transduction pathways?

JAK-STAT pathway

Signal Transducer and Activator of Transcription (STAT) proteins are activated by which of the following kinases?

Janus kinases (JAKs)

Which of the following are intermediate filament proteins that are exclusively expressed in epithelial cells?

Keratins

Which of the following kinesin motor proteins binds directly to chromatins?

Kinesin 4,10

which of the following amino acid sequence marks a protein for retention in ER lumen?

LYS-ASP-GLU-LEU-COOH (KDEL) -these proteins also displayed an N-terminal ER signal sequence which is removed by proteolysis after cotranslational transport into the ER lumen

Many mitochondrial proteins are encodes in the nuclear genome. These proteins are translated in the cytosol and transported into the mitochondrion, where the first enter which of the following comportments?

The matrix

During insulin-mediated upregulation of glucose transporters on the plasma membrane, glucose uniporters are delivered to the plasma membrane in vesicles derived from which of the following compartments?

Recycling endosomes

During the insulin-mediated increase in glucose uptake into cells, glucose uniporter are delivered to the plasma membrane in vesicle derived form which of the following compartment?

Recycling endosomes

Which of the following events occurs immediately after GTP hydrolysis by elongation factor Tu?

Release of the aminoacyl t-RNA in the A-site of the ribosome

Which of the following is responsible for the DIRECTIONALITY of transport through the nuclear pore complex?

Restriction of RAN-GEF to the nuclear compartment

The directionality of the transport across the nuclear envelope via the nuclear pore complex us due primarily to which of the following conditions

Restriction of Ran-GEF to the nuclear compartment

Which of the following is most likely the fate of a protein marked with a KDEL signal sequence at the C-terminal?

Return to the ER lumen

Which of the following monomeric G-proteins is involved in remodeling of the actin cytoskeleton?

Rho

Which of the following model organism was used to elucidate the transmembrane ion conductances responsible for the generation and propagation of action potentials?

Squid

Agents that interfere with the dynamic instability of microtubules, including Taxol, cholchicine, and vincristine, are effective anti-cancer chemotherapeutics. Why is taxol less toxic to normal cells?

Taxol actually stabilizes microtubules

How does the calcium-dependent ER chaperone protein, Calnexin recognize and bind proteins that may be misfolded?

The oligosaccharide on the asparagine residue of the protein has one terminal glucose moiety

Which of the following is an important function of heat shock proteins?

They help soluble proteins fold properly

Which of the following statement regarding cytoplasmic is true?

They hydrolyze ATP and move toward the minus (-) end of microtubules

Which of the following statement is TRUE regarding most kinesin motor proteins?

They hydrolyze ATP and move toward the plus (+) end of microtubules

During the transport cycle for the sodium-potassium ATPase, which events occurs immediately after phosphorylation an aspartate residue on the phosphorylation domaterm-4ins?

Transport of 3 sodium ions from the cytosolic compartment to the extracellular compartment

During the formation of clathrin-coated vesicles, a heximeric protein complex of clathrin proteins binds to adaptin molecules to form the clathrin cage. What is the name of this protein complex?

Triskelions

Cytosolic domains of plasma membrane proteins remain in the cytosol throughout transport through the Golgi

True

In some cells, activation of phospholipase C-beta causes waves of released Ca2+ to spread along the cytoplasmic surface of the endoplasmic reticulum.

True

Only the extracellular domains of membrane glycoproteins can be glycosylated.

True

Transport of soluble protein from the cytosol into the mitochondrion required the establishment of the a pH gradient across the inner mitochondrial membrane

True

True or False? "Only the extracellular domains of membrane glycoproteins can be glycosylated."

True

immediately after release of the vesicles from the source membrane, the coat proteins dissociate

True

A membrane protein whose primary structure structure includes an N-terminal ER signal sequence and 2 internal run of 8 or more consecutive non-polar amino acids will undergo co-translation transport at the ER. Which of the following best describes the orientation of the membrane proteins in the ER membrane

Two transmembrane domain with the C and N terminals on the same side of the ER membrane

Which of the following statements regarding ubiquitin-mediated proteolysis is true?

Ubiquitin activation requires ATP hydrolysis The first ubiquitin molecule is attach3ed to the epsilon amino group of a lysine residue on the target protein A chain of ubiquitin molecules directs the target protein to the 20S proteasome

11. Which of the following best describes the orientation of a protein in the ER membrane that contains three internalhydrophobic domains, but no N-terminal hydrophobic domain? a) three transmembrane alpha helices with N-terminal in the cytosol b) three transmembrane alpha helices with N-terminal in the ER lumen c) two transmembrane alpha helices with N-terminal in the ER lumen d) two transmembrane alpha helices with C-terminal in the cytosol e) two transmembrane alpha helices with N-terminal and C-terminal on opposite sides of ER membrane

2. During the unfolded protein response, which of the following "misfolded protein sensors" in the ER membrane signals through a cytosolic ribonuclease domain by excising an intron from a pre-existing mRNA molecule? a) IRE1 b) PERK c) ATF-6 d) all of the above e) none of the above

28. Which of the following substrates is phosphorylated by the PI3 kinase? a) phosphatidylinositol 4,5-bisphosphate b) phosphatidylinositol 3,4,5-trisphosphate c) inositol 1,4,5-trisphosphate (IP3) d) all of the above e) none of the above

3. Is the following statement TRUE or FALSE? "In some cells, activation of phospholipase Cbeta causes waves of Ca2+ release to spread along the endoplasmic reticulum." a) the above statement is TRUE b) the above statement is FALSE

36. Which of the following proteins is most highly expressed during the unfolded protein response? a) chaperone proteins b) SNARE proteins c) nuclear transport receptors d) RNA polymerase e) Akt kinase

37. Which of the following small GTPases plays a key role in the mitogen activated protein (MAP) kinase pathway? a) Ras d) Ran b) Rac e) Erk c) Rab

45. Which of the following is the calcium sensor that facilitates exocytotic release of neurotransmitter at the presynaptic terminal? a) synaptotagmin b) synaptobrevin c) syntaxin d) SNAP25 e) none of the above

48. Which of the following best describes the gaseous messenger, nitric oxide a) it is a paracrine messenger produced from arginine b) it is a paracrine messenger produced from asparagine c) it is an endocrine messenger produced from arginine d) it is an endocrine messenger produced from asparagine e) it is a byproduct of nitrogen metabolism

5. Is the following statement TRUE or FALSE? "Cytosolic domains of plasma membrane proteins remain in the cytosol throughout transport through the Golgi." a) the above statement is TRUE b) the above statement is FALSE

7. In the lab, you have cultured cells that express a trimeric G protein of the Gs family. Which of the following best describes the expected result of cholera toxin treatment on these cells? a) cAMP levels go up b) cAMP levels go down c) cGMP levels go up d) IP3 levels go up e) IP3 levels go down

In many protein complexes, amphipathic alpha helices on different protein subunits interact to form a very stable structure called ...

a coiled coil

Which of the following is the most common transmembrane domain of integral membrane proteins?

a hydrophobic alpha helix

A protein domain that is found in many otherwise unrelated proteins is frequently described described as which of the following?

a module

During the formation of intraluminal vesicles, which of the following recruits the ESCRT0 complex to the endosomal membrane

a phosphoinositide

during the formation of intraluminal vesicles what recruits the ESCRT0 complex to the endosomal membrane ?

a phosphoinositide 1. membrane proteins "targeted" by ubiquination 2. ESCRT0 recruited by PI3 (phosphoionositde) 3. sequestration and capture in intraluminal vesicles

Which of the following best describes the orientation within the ER membrane of a protein with an N-terminal ER sorting sequence, and three internal runs of 8 or more non-polar amino acids?

a protein with three transmembrane alpha helices and the C-terminus in the cytosol

Many anti-cancer drugs target the microtubule cytoskeleton. Which of the following best describes this class of anti-cancer drugs?

a) drugs that destabilize microtubules b) drugs that stabilize microtubules c) drugs that prevent microtubule polymerization d) drugs that promote microtubule polymerization

collagen?

a) it is the most abundant protein in mammals b) every third amino acid is a glycine c) it is a trimeric, coiled coil. d) vitamin C is required for biosynthesis

Apoptosis can be induced by which of the following?

a) release of cytochrome C from mitochondria b) pro-caspase activation c) aggregation of BH123 proteins d) loss of survival factor signaling

Lysozyme is an antimicrobial enzyme found in saliva. Which of the following statements about lysozyme is TRUE

a)It is a polysaccharide hydrolase b) It binds to 6 sugar residues of the substrate c) It employs coordinated acid base catalysis d) Binding of the substrate results in distortion of the "D" ring

Why are disulfide bridges rarely found in cytosolic domains of membrane proteins?

because cytosolic constituents promote reduction of disulfide bonds

during signaling through a trimeric G protein, how is the action of the beta gamma complex terminated?

binding to the GDP bound form of the alpha subunit 1. hydrolysis of the GTP by the a-subunit inactivates this subunit and causes it to dissociate from the target protein 2. inactive alpha subunit reassembles with b-y complex to reform an inactive g protein -target protein act as GAP lec 13b

How do activated T-cells initiate apoptosis via the extrinsic pathway

by activating the Fas death receptor on target cells

How might the Golgi complex monitor the "progress" of post-translational protein processing?

by modifications of the N-oligosaccharide

How does the Akt kinase promote cell survival?

by phosphorylating and inactivating the BAD protein

How does the AKT kinase inhibit apoptosis?

by phosphorylating the BAD protein and releaseing the anti-apoptotic protein Bcl2

How does the anti-apoptotic protein, Bcl2, prevent apoptosis?

by preventing the aggregation of "BH123" proteins

How does p53 activation prevent entry into S-Phase?

by promoting the synthesis of Cdk inhibitors

When significant DNA damage is detected during G1 phase, P53 released from inhibition and arrests cell cycle at the start checkpoint to prevent replication of damage DNA. How does P53 prevent entry into S phase

by promoting the transcription of Cdk inhibitor

During embryonic development, how does the Notch receptor signal that it has bound a Delta ligand?

by releasing a proteolytic fragment of the receptor into the cytosol

Prior to vesicle formation, how are adaptins recruited to the appropriate membrane.

by specific phosphoinositides on the cytosolic surface

12. Which of the following best describes the orientation of a protein in the ER membrane that contains N-terminal ER localization signal and two internal hydrophobic domains? a) three transmembrane alpha helices with N-terminal in the ER lumen b) three transmembrane alpha helices with N-terminal in the cytosol c) two transmembrane alpha helices with N-terminal in the ER lumen d) two transmembrane alpha helices with C-terminal in the cytosol e) two transmembrane alpha helices with N-terminal and C-terminal on opposite sides of ER membrane

20. Signal Transducer and Activator of Transcription proteins (STATs) are activated by which of the following kinases? a) Protein kinase A b) Mitogen activated kinases c) Janus kinases d) Calcium-calmodulin dependent protein kinase II e) none of the above

22. Which of the following best describes the events that occur after photoisomerization of 11-cis retinal in rod cells? a) cGMP levels increase, Na+ channels open, the cell depolarizes, and glutamate release increases b) cGMP levels decrease, Na+ channels close, the cell depolarizes, and glutamate release increases c) cGMP levels decrease, Na+ channels close, the cell hyperpolarizes and glutamate release decreases d) cGMP levels increase, Na+ channels close, the cell depolarizes, and glutamate release increases e) None of the above

9. Directional transport through nuclear pore complexes is due, in part, to which of the following? a) a gradient of GTP across the nuclear envelope b) a gradient of ATP across the nuclear envelope c) restriction of RAN-GEF to the nuclear compartment d) restriction of RAN-GEF to the cytosolic compartment e) restriction of RAN-GAP to the nuclear compartment

Choose from the following amino acid sequences as you answer questions 56-58. a) NYLSCKDEL b) APPRRRKRV c) MLAVALVIA d) LRNSIRFFLK e) GATALACAT 58. Which of the above N-terminal sequences could direct a secretory protein to the ER membrane for co-translational transport?

In the lab, you have cultured cells that express a trimeric G protein of the Gs family. Which of the following best describes the expected result of cholera toxin treatment on these cells?

cAMP levels go up

In the lab, you have cultured cells that express a trimeric G protein of the Gs family. Which of the following best describes the expected results of cholera toxin treatment of these cells

cAMP levels go up

in the lab you have cultured cells that express a trimeric G protein of the Gs family, which of the following best describes the expected result of cholera toxin treatment of these cells

cAMP levels go up -CHOLERA: inhibit GTPase locked "ON" = Increase cAMP -PERTUSSIS: inhibit exchange locked "OFF" = increase cAMP

Which of the following best describes the events that occur after photoisomerization of 110cis retinal in rod photoreceptor cell?

cGMP level decrease, Na+ channels close, the cell hyperpolarize, and glutamate release decreases.

what best describes the events that occur after polymerization of 11-cis retinal in rod photoreceptor cells

cGMP levels decrease, NA channels close, cells hyper polarize, glutamate release decrease dark current - in the dark the cytosolic cGMP is very high due to gauntly cyclase activity -cGMP actiivates ligad gated Na channels holding the channels open = dark current of Na influx signal cascade - light drives the photoisomerization of 11-CIS retinal to all TRANS -opsin is activated -opsin activates Gt (transducin) -cGMP phosphodiesterase is activated - this will degrade cGMP -NA channels close -light causes hyperpolarization -decrease in neurotransmitter (neurotransmitter is glutamic acid)

Which of the following best describes the events that occur after photoisomerization of 11-cis retinal in rod photoreceptor cells?

cGMP levels decrease, Na+ channels close, the cell hyperpolarizes and glutamate release decreases

In the retina, photoisomerization of 11-cis retinal activates rhodopsin, which, in turn, activates the trimeric G-protein, Gt (transducin). Which of the following membrane associated enzymes is activated by Gt?

cGMP phosphodiesterase

in rod cells of the vertebrate retina, photoisomerization of 11-cis retinal activates rhodopsin which, in turn activates the trimeric G protein (transducin) which membrane associated enzyme is activated by the alpha subunit of Gt?

cGMP phosphodiesterase signal cascade 1. light drives the photoisomerization of 11-CIS retinal to all TRANS 2. opsin is activated 3. opsin activates Gt (transducin) 4. the previous activation does this: cGMP phosphodiesterase is activated

In rod cells of the vertebrate retina, photoisomerization of 11-cis-retinal activated rhodopsin which, in turn, activates the trimeric G-proteins, Gt. Which of the following membrane -associated enzymes is activated by the alpha subunit of Gt.

cGMP phphosphodiesterase

Drugs like Viagra work by inhibiting which of the following proteins?

cGMP specific phosphodiesterase

drugs like viagra work by inhibiting which of the following enzymes?

cGMP specific phosphodiesterase -"drug companies raced to develop cGMP PDE inhibitors "

Drug like Viagra work by inhibiting which of the following enzyme

cGMP-specific phosphodiesterase

Which of the following proteins is/are NOT (an) ABC transporter(s)?

calcium ATPase

At the M-phase checkpoint, which of the following proteins is the phosphates that removes the inhibitory phosphate group for M-cdk complex?

cdc25

Which of the following proteins is required to sustain APC activity during G1? a) cyclin D d) p53

cdh1

Which of the following proteins replaces cdc20 to maintain anaphase promoting complex activity during G1 phase

cdh1

most transport vesicles destined for the endosomal system are formed by which of the following coat proteins?

clathrin - these vesicles sort between the golgi, endosomes, and PM (TRANS GOLGI TO PM)

An antiporter mediates, which of the following processes?

co-transport a solute molecule against its concentration gradient and an ion along its concentration gradient in opposite direction across the plasma membrane

An ANTIPORTER mediates which of the following processes?

co-transport of a solute molecule against its concentration gradient, and an ion along its concentration gradient in opposite directions across the plasma membrane

Which of the following proteins promotes the depolymerization of actin filaments

cofilin

Which of the following proteins promotes the depolymerization of actn filament near the lamellipodium?

cofilin

Which of the following refers to the proteins that are cleaved by separase to release sister chromatids at anaphase?

cohesins

Ethler Danlos disease is characterized by defects in the synthesis of which of the following proteins?

collagen I

Scurvy is a disease characterized by defects in the synthesis of which of the following proteins?

collagen I

Which of the following refers to the SMC protein complex that gathers and organizes newly replicated DNA into chromosomes?

condensin

What is the term for the SMC protein complexes that gather and pack newly replicated DNA into chromosomes?

condensins

Which of the following microscopic techniques supports three dimensional reconstruction from optical sections obtained from a fluorescent specimen?

confocal laser scanning microscopy

The incorporation of a small aperture ("pinhole") near the detector that limits the transmission of out-of-focus light emitted from the specimen is an important feature of which of the following optical techniques?

confocal microscopy

When a catalytic subunit of the cyclic AMP-dependent protein kinase enter the nucleus, it phosphorylate which of the following transcription factor.

cyclic AMP response element binding (CREB) protein

when catalytic subunit of the cyclic AMP dependent protein kinase (PKA) enters the nucleus. it phosphorylates which transcription factor?

cyclic AMP response element binding CREB protein -PKA enters the nucleus where it phosphorylates other target proteins including transcription factors like CREB -PKA can activate gene expression by phosphorylating CREB

19. The effect of cholera toxin treatment on trimeric G-protein signaling is due to which of the following covalent modifications? a) ubiquitination of the alpha subunit b) ADP ribosylation of the alpha subunit c) phosphorylation of the alpha subunit d) phosphorylation of the beta-gamma complex e) dephosphorylation of the beta-gamma complex

23. Most clathrin-coated vesicles are destined for which of the following cell compartments? a) endoplasmic reticulum b) endosomes c) cis Golgi network d) nucleus e) mitochondria

29. In some cells, the catalytic subunit of protein kinase A (PKA) can enter the nucleus and alter gene expression by phosphorylating which of the following proteins? a) transcription factor A b) cyclic AMP response element binding (CREB) protein c) CREB binding protein (CBP) d) calmodulin e) none of the above

40. Proteins expressing a C-terminal KDEL sequence are returned to the ER in which of the following? a) clathrin-coated vesicles b) COP1 vesicles c) COP2 vesicles d) in caveoli e) diffusion through the cytosol

44. Signal mediated up-regulation of cell surface receptors involves the transfer of sequestered receptors from which of the following compartments? a) late endosomes b) recycling endosomes c) the trans-Golgi network d) the endoplasmic reticulum e) secretory vesicles

46. What is the term for a receptor that indirectly activates an ion channel on the plasma membrane. a) ionotropic b) metabotropic c) pleotropic d) isotropic e) bizarre

50. Viagra and related drugs affect the nitric oxide signaling pathway by acting on which of the following signaling molecules? a) guanylyl cyclase b) cGMP phosphodiesterase c) adenylyl cyclase d) cAMP phosphodiesterase e) none of the above

53. Prolactin and cytokines signal through which of the following? a) receptor tyrosine kinases b) JAK kinases c) PKA d) Akt kinase e) G-protein coupled receptors

54. In the MAP kinase pathway, the small GTPase, Ras, is activated by recruitment of which of the following proteins? a) STATs b) Ras-GEF c) Ras-GAP d) PKC e) Rasactin

Choose from the following amino acid sequences as you answer questions 56-58. a) NYLSCKDEL b) APPRRRKRV c) MLAVALVIA d) LRNSIRFFLK e) GATALACAT 56. Which of the above internal signal sequences could direct proteins to the nuclear compartment?

17. Viagra and related drugs affect the nitric oxide signaling pathway by acting on which of the following signaling molecules? a) adenylyl cyclase b) cAMP phosphodiesterase c) guanylyl cyclase d) cGMP phosphodiesterase e) none of the above

18. Which of the following proteins directs vesicles to the proper target membrane? a) clathrin b) dynamin c) SNARE proteins d) Rab proteins e) tethering proteins

21. Growth factors signal through the PI3 kinase pathway. Which of the following protein complexes is activated during growth factor signaling, and both promotes protein synthesis, and inhibits protein degradation? a) ribosome b) ubiquitin ligase complex c) spliceosome d) mTOR complex e) none of the above

24. During receptor mediated endocytosis, which of the following events releases clathrin-coated vesicles from the plasma membrane? a) phosphorylation of clathrin b) dephosphorylation clathrin c) GTP hydrolysis by the RAB GTPase d) GTP hydrolysis by the dynamin complex e) dissociation of the clathrin coat

25. During vesicle formation at the plasma membrane, clathrin triskelions bind to which of the following proteins? a) cargo proteins b) cargo receptors c) adaptin receptors d) adaptins e) none of the above

30. During cell signaling through G-protein coupled receptors, what event enables binding of the alpha subunit to the beta-gamma complex? a) exchange of bound GDP for GTP on the alpha subunit b) exchange of bound GDP for GTP on the beta-gamma subunit c) GTP hydrolysis by the beta-gamma complex d) GTP hydrolysis by the alpha subunit e) dephosphorylation of the alpha subunit

43. At the intestinal epithelium of the neonatal gut, maternal antibodies present in breast milk are acquired by receptor-mediated endocytosis across the apical membrane. How are they delivered to the interstitial compartment? a) they are passively transported across the basolateral membrane b) they are actively transported across the basolateral membrane c) they are packaged into transport vesicles by early endosomes d) they are packaged into secretory vesicles by recycling endosomes e) they are processed at the level of the gut epithelium and do not enter the interstitial compartment.

51. Which of the following events terminates signaling through the alpha subunit of a trimeric G-protein complex? a) dissociation of the ligand-receptor complex b) dissociation of the G-protein from the receptor c) GTP exchange d) GTP hydrolysis e) binding of the G-alpha subunit to the beta-gamma complex

during early development of the vertebrate CNS, undifferentiated epi cells enter the neuronal lineage signal to their neighbors by displaying which membrane protein?

delta delta is the signal -membrane bound inhibitory signal protein - receptor protein: notch -tells the other ones NOT to become a neuron - notch activation prevents differentiation into neurons

Un-capped actin filament "grow" (polymerize) at the plus (+) end. What happens at the minus end?

depolymerization

Which of the following cell-cell junctions is formed by cell adhesion molecules that are associated with intermediate filaments?

desmosomes

In addition to the activation of the cyclin-dependent protein kinase, what is the role of the cyclin subunit?

determines the substrate specificity of the kinase

What is a role of the cyclin component of Cdk complexes (e.g., M-Cdk)?

determines the substrate specificity of the kinase

what are caveolae?

small endocytic vesicles containing membrane proteins and sphingomyelin -are a special type of lipid raft made, are small invaginations of the plasma membrane -can bud from the plasma membrane to form endocytic vesicle or can flatten into the membrane to help withstand stress - abundant in endothelial cells beloved to play a role in vesicular trafficking and signal transduction

In epithelial cells, how is glucose transported across the apical membrane?

sodium-glucose symporter

Which of the following proteins transports sodium ions against their concentration gradient?

sodium-potassium ATPase

Which of the following proteins determines the packing density of microtubules in axons?

tau

what occurs after a nuclear EXPORT receptor binds to RAN-GTP?

the cargo protein binds with high affinity -cargo site is stabilized and cargo binds with high affinity - when ran gtp binds to IMPORT the cargo site is disrupted and the cargo protein dissociates

The aqueous channel of the aquaporin complex has a pair of key asparagine residues located almost halfway through along the channel. These residues form hydrogen binds with the oxygen atoms of a single water molecule, rendering it unavailable for additional hydrogen-bonding. Which of the following best describe the consequence of this structural feature?

the channel cannot conduct protons

Aquaporin has a pair of key asparagine residues located on the wall almost halfway through its pore. These residues simultaneously bind to the oxygen atom of a passing water molecule, rendering it unavailable for hydrogen-bonding. As a result, ...

the channel cannot conduct protons.

Which feature of the cyclin dependent kinase (Cdk) complex determines the substrate specificity of the kinase?

the cyclin subunit

What is a "Stokes Shift"?

the difference between the peak absorbance and peak emission wavelengths of a fluorochrome

many mitochondrial proteins are encoded in the nuclear genome. these proteins are translated in the cytosol and transported into the mitochondria , where they first enter which compartment?

the matrix -mitocondrial proteins are first sorted to the matrix space - transported into mitochondria in unfolded state powered by H gradient and ATP hydrolysis

During kinesin movement along a microtubule, which event causes the neck linker to "zipper onto the head domain" (i.e., the "Power Stroke")

dissociation of Pi

during nuclear import, what happens immediately after the binding of RAN GTP to the nuclear import receptor (NIR)

dissociation of cargo protein from the NIR -when ran-GTP is bound to NIR, cargo site is disrupted and cargo protein dissociates (IMPORT) -when ran-GTP is bound to NER, cargo site is stabilized and cargo binds (EXPORT)

During nuclear import, what happen IMMEDIATELY AFTER the binding of Ran-GTP to the nuclear import receptor?

dissociation of the cargo protein from the NIR

the ability of vesicles to fuse with the target membrane is maintained at the expense of ATP hydrolysis . when does ATP hydrolysis occur?

during dissociation of SNARE proteins -step 16 Trans - SNARE complexes dissociate. this process is powered by ATP hydrolysis via the NSF complex (a AAA atpase)

which monomeric GTPASE provides energy for release of newly formed vesicles from the source membrane?

dynamin - the dynamin complex includes additional proteins that facilitate membrane fusion and release of vesicle - powered by GTP hydrolysis

t/f no molecule can transverse the nuclear pore complex with out the assistance of a nuclear transport receptor

false -small 5kD molecules pass freely in both directions - most soluble proteins must be escorted through the NPC - Most proteins require escort all greater than 60 kD proteins do -proteins are escorted through the nuclear pore complex by nuclear transport receptors

For which of the following ions is the intracellular concentration typically higher than the extracellular concentration?

potassium ions

The resting potential of the plasma membrane is primarily due to selective permeability of the membrane to which of the following ions?

potassium ions

The resting potential of the plasma membrane of an excitable cell is primarily due to the selective permeability of the membrane to which of the following ions?

potassium ions

Which of the following is NOT a component of the basal lamina?

fibronectin

Vinculin, together with Talin dimers, couple integrin dimers to the actin cytoskeleton in which of the following cell-cell matrix junctions ?

focal adhesions

Which of the following cell-matrix junctions is formed by cell adhesion molecules that are associated with actinfilaments?

focal adhesions

Which of the following actin binding proteins is capable of nucleating the formation of new actin filaments?

formin

Which of the following proteins complexes can nucleate actin polymerization in the absence of existing actin filament

formin dimers

which of the following is the largest family of cell signaling proteins encoded in the human genome

g protein coupled receptors -transient activation of a G protein which usually signals through a membrane associated enzyme -involves significant amplification step

The alpha helix is stabilized by which of the following interactions?

hydrogen bonds between elements of the peptide backbone

during endosomal maturation, the luminal concentration of which ions gradually increases, with the highest concentration occurring in lysosomes?

hydrogen ions (lec 12) -as they mature the luminal ph gradually falls (more acidic) - enzymes only active at a low ph - V type transporter pumps protons (H) into the organelle

Where in a motile cell would you expect to find most of ARP complex?

in the lamellapodium

the SRP binds to the ER sorting signal on the nascent polypeptide and stops translation. when does translation resume ?

immediately after binding of the sorting sequence to the ER translocator SEC61 - the polypeptide chain passes through an aqueous channel in the translocator COTRANSLATIONAL TRANSPORT - 1. translation of the protein is "arrested" as SRP binds 2. translation resumes when SRP dissociates -sorting signal incorporated into PRIMARY structure of polypeptide - SRP directs the ER signal sequence to a specific receptor in the ROUGH ER membrane -SRP= 6 protein subunits -SRP recognizes and binds to the ERSS & blocks the A site to halt translation

Which of following modifications would result in increased membrane fluidity?

increased amount of unsaturation of fatty acid tails

Which of the following is likely to decrease the fluidity of a phospholipid bilayer?

increased saturation in fatty acid tails

All cell-matrix junctions include which of the following cell adhesion molecules?

integrin dimers

protein componets of the ESCRT system are responsible for the formation of which of the following vesicles?

intraluminal vesicles - early endosomes gradually mature into multivesicular bodies -intralumenal vesicles form by ESCRT mediated invagination of the endosomal membrane

Which of the following is/are true regarding the NMDA receptor?

it is a glutamate-gate calcium channel in the resting state, the channel is blocked by a single magnesium ion it is involved thought to be involved in the molecular mechanism underlying learning and memory in the brain sustained activation often results in an increase in the density of glutamate receptors on the postsynaptic membrane

Which of the following statements is True regarding the immunoglobin molecules?

it is a heterotetramer composed of two light chains and two heavy chains there are two antigen binding domains The antigens binding domain(s) includes elements of both the light and heavy chains the light and heavy chains are stabilized by disulifde bonds

How is phosphatidylserine different from all other phospholipids?

it is negatively charged at neutral pH

What is the function of the centriole?

it is required for production of cilia

what is the function of synaptobrevin?

it is the V-SNARE on the synaptic vesicle -physically pulls synaptic vesicle to pre synaptic PM

What is the function of cdc25?

it is the phosphatase that dephosphorylates cdk1 at the inhibitory site

How is cyclin B inactivated at the metaphase-anaphase transition?

it is ubiquinated by APC

How does cytochrome C initiate apoptosis?

it promotes the aggregation of initiator procaspases

Which of the following is FALSE regarding bacteriorhodopsin?

it pumps protons into of the cytosol

Phospholipase C-beta activation leads to the production of two signaling molecules; inositol 1,4,5-triphosphate and diacylglycerol. What is the function on IP3

it simulates release of Ca2+ from smooth ER

Phospholipase C-beta activation leads to the production of (at least) two signaling molecules; inositol 1,4,5-trisphosphate (IP3) and diacylglycerol. What is the function of IP3?

it stimulates the release of calcium from the smooth ER

Which of the following is the intermediate filament that is exclusively expressed in epithelial cells?

keratins

Which of the following kinesin promotes catastrophic depolymerization of microtubules?

kinesin 13

Which of the following kinesin proteins plays a key role in the Anaphase A process?

kinesin 13

Which of the following kinesin proteins is capable of binding directly to chromatin?

kinesin 4,10

What is the term for the relatively thick regions of the plasma membrane into which sphingomyelin and signaling proteins are often concentrated?

lipid rafts

during processing in the Golgi complex, which protein becomes labeled with mannose 6 phosphate tag?

lysosomal acid hydrolases - only properly folded proteins display characteristic signal patches identifying them as lysosomal hydrolases receive M6P tags. these proteins are often in pro enzyme forms. -hydrolytic enzymes destined for the lysosomes are tagged in the golgi by one or more M6P moieties - these enzymes only active around ph 5 often biosynthesized in pro enzyme form that is activated by proteolysis in the lysosome

Growth factors signal through the PI3 kinase pathway. Which of the following protein complexes is activated during growth factor signaling, resulting in increased protein synthesis, and decreased protein degradation?

mTOR complex

The endosymbiosis hypothesis concerns which of the following organelles ?

mitochondria and chloroplasts

The endosymbiosis hypothesis concerns which of the following organelles?

mitochondria and chloroplasts

how does the golgi complex monitor the progress of post translational protein processing

modifications of the N-oligosaccharide - "in this way, the pattern of glycosylation records progress through the golgi to the target membrane" -oligosaccharides are used as tags to mark the state of protein folding

Which of the following events is mediated by a calcium-gated calcium channel?

muscle contraction

During G1 phase, which of the following prevents entry into S-phase when DNA damage is present?

p53

Which of the following fungal products binds to and stabilizes actin filaments?

phalloidin

Which of the following phospholipid is negatively charged at neutral pH?

phosphatidyl serine

Which of the following substrates is phosphorylated by the PI3 kinase?

phosphatidylinositol 4,5-biphosphate

Which of the following substrates is phosphorylated by the PI3 kinase?

phosphatidylinositol 4,5-bisphosphate

During the transport cycle of the calcium ATPase, which of the following events causes the conformation change that enables transport of 2 calcium ions out of the cytosol?

phosphorylation of an aspartate residue

Proteins that contain an SH@ domain are likely to bind to which of the following structural features of a protein partner?

phosphotyrosine residue

Proteins that contain an SH3 (src homology 3) domain are likely to bind to which of the following features of a protein partner?

proline-rich domain

The nuclear envelope disintegrates during which phase of mitosis?

prometaphase

What are Caspases?

proteases that cleave substrates at specific aspartate residues

during the insulin mediated increase in glucose uptake into the cells, glucose uniporters are delivered to the plasma membrane in vesicles derived from which compartment?

recycling endosomes -insulin, secreted in response to elevated blood glucose, binds to insulin receptors on adipose and muscle cells, results din signal mediated up regulation of glucose transporters by releasing vesicles containing sequestered transporters from recycling endosomes - glucose transporter is Glut4 uniporter (facilitated diffusion)

During receptor mediated endocytosis, endocytic vesicles fuse with early endosomes. In some cases, the cytosolic domains of endocytosed membrane proteins are ubiquinated by cytosolic ubiquitin ligase. What is the fate of these proteins

they are incorporated into intralumenal vesicles and degraded in endolysosomes

during receptor mediated endocytosis, endocytic vesicle fuse with early endosomes. in some cases, the cytosolic domains of endocytosed membrane proteins are ubiquinated by cytosolic ubuitin ligases. what is fate of these proteins?

they are incorporated into intraluminal vesicles and degraded into endolysosmes -improperly folded proteins are exported from the ER and degraded in the cytosol

What is the role of dynein motor proteins in the assembly of the spindle complex?

they bind to astral microtubules and pull the spindle poles apart

Which of the following is TRUE regarding most kinesin motor proteins?

they hydrolyze ATP and move toward the plus (+) end of the microtubule

What is the function of gamma tubulin ring complexes?

they nucleate polymerization of microtubules

Which of the following cell-cell junctions is responsible for preventing the diffusion of solutes between apical and basolateral extracellular compartments in epithelial tissues?

tight junctions

Which of the following best describes the apical-to-basolateral order of occurrence of cell-cell junctions in an epithelial cell?

tight junctions - adherens junctions- desmosomes - gap junctions

the destination for vesicles containing mature proteins is determined in which of the following compartments

trans golgi network - controls distribution of outgoing membrane secretory proteins lec12 WRITE MORE NOTES ON THIS

Within the Golgi complex, where would you expect to find mannose-6-phosphate (M6P) receptors?

trans-Golgi network

within the golgi complex, where would you expect to find mannose-6-phosphate receptors?

trans-golgi network -modifications of the N-linked oligosaccharide chain of glycoproteins mark their "maturation" as they are processed through the golgi -trans golgi netwrok controls the distribution of outgoing membrane and secretory proteins

During the transport cycle for the sodium-potassium ATPase, which event occurs immediately after dephosphorylation of the critical aspartate residue?

transport of 2 potassium ions from the extracellular compartment to the cytosolic compartment

go back to test

true

transport of soluble proteins from the cytosol into the mitochondria requires the establishment of a PH gradient across the inner mitochondrial membrane t/f

true -ATP hydrolysis and a membrane potential drive protein import into the matrix space -transported into the mitochondria in unfolded stated powered by H gradient and ATP hydrolysis

cytosolic domains of the plasma membrane proteins remain in the cytosol throughout the transport through the Golgi t/f

true -what is cytosolic remains cytosolic

t/f immediately after release of coated vesicles from the source membrane, the coat proteins dissociate

true 1. cargo receptor bind to cargo protein in the TGN lumen 2.receptor complexes recruit adaptins 3. adaptins recruit coat proteins (clathrin) 4. clathrin network deforms the membrane (pit) 5. pit rounds into a vesicle 6. dynamin(GTPase) binds to stalk 7. gtp hydrolysis powers release of the vesicle 8. after release the coat proteins dissociate

in some cells activation of phospholipase c beta causes waves of released Ca to spread along the cytoplasmic surface of the ER t/f?

true -calcium activated calcium channels drive propagation of calcium waves along the ER -activation of phospholipase C by GCPRs calcium channel is activated (on) releases calcium

Which of the following events is responsible for the repolarization phase of the action potential? a) opening of voltage gated sodium channels b) opening of voltage gated potassium channels c) inactivation of voltage gated sodium channels d) two of the above e) all of the above

two of the above

a membrane protein whose primary structure includes an N terminal ER signal sequence and 2 internal runs of 8 or more consecutive non polar amino acids will undergo co-translational transport at the ER. what describes the orientation?

two transmembrane domains with the C and N terminals on the same side of the ER membrane

At the metaphase-anaphase checkpoint, which of the following events must occur for mitosis to proceed?

ubiquination of cyclin B

Tertiary structure of proteins is primarily stabilized by which of the following?

van der Waals attractions between hydrophobic amino acid side chains

Tertiary structure of proteins is primarily stabilized by which of the following non-covalent bonds?

van-der-Waals attraction between hydrophobic amino acid side chains

Neurotransmitter release from the presynaptic terminal requires the activation of which of the following ion channels?

voltage grated calcium channels

Which of the following is a substrate for M-Cdk complex

wee1 cdc25 lamin B

During dynamic instability of microtubules, when does the "catastrophic" shortening of microtubules occur?

when the microtubule loses its "GTP cap"

When is a misfolded protein considered to be a "prion"?

when the protein transmits disease to other organisms

Which of the following statements is FALSE regarding the nuclear pore complex? A. small molecules (<5kD) readily diffuse through NPCs B. proteins are unfolded during transport through NPCs C. only proteins with exposed nuclear import signals can enter the nucleus through NPCs D. all proteins require a nuclear transport receptor to pass through NPCs E. all of the above are true regarding NPCs

B. proteins are unfolded during transport through NPCs

Disintegration of the nuclear lamina and the nuclear envelope occurs during which phase of mitosis?

Prometaphase

Which of the following is the inhibitory binding partner for transcriptions factor E2F?

Rb protein

In a Lineweaver-Burk plot of the dependence of enzyme velocity on substrate concentration, what is the value of the function at Y=0?

-1/km

Which of the following amino acid sequence marks a protein for retention in the ER lumen

... -Lys-Asp-Glu-Leu-COOH

Which of the following amino sequence does NOT mark the asparagine residue for N-glycosylation?

...N-A-P...

Proteins with one or more amphipathic alpha helices are uniquely capable of forming which of the following structural features?

A coiled coil

Which of the following proteins assists in activating a typical G-protein?

A guanine nucleotide exchange factor

Which of the following signal sequences will most likely ID a protein for importation into the nucleus? A. -P-P-K-K-K-R-K-V- B. -R-R-K-K-K-P-K-A- C. -P-P-L-L-L-R-L-A- D. -P-P-K-K-K-K-K-G-

A. -P-P-K-K-K-R-K-V-

Which of the following amino acid sequences identifies a soluble protein for nuclear import? A. -Pro-Pro-Lys-Lys-Arg-Lys-Lys-Val- B. -Ser-Lys-Leu-COOH C. -Lys-Asp-Glu-Leu-COOH D. -Met-Met-Leu-Leu-Leu-Val-Gly-Ile-Leu-Phe-Trp-Ala-Thr-Glu

A. -Pro-Pro-Lys-Lys-Arg-Lys-Lys-Val-

Protein kinase A often activates gene expression by phosphorylating which of the following proteins? A. CREB protein B. CREB binding protein C. STAT D. MAP kinase

A. CREB protein

N-glycosylation begins in which compartment? A. ER B. Golgi C. endosomes D. secretory vesicles E. lysosome

A. ER

What is BIP? A. ER resident protein B. mitochondrial chaperone protein C. cytoplasmic chaperone protein D. none of the above

A. ER resident protein

Application of a GPCR agonist increases phospholipase C-beta activity. This effect is not blocked by high concentrations of pertussis toxin. Therefore, this GPCR is probably signaling through which of the following trimeric G-proteins A. Gq B. Gt C. Gi D. Gs E. Go

A. Gq

Cholera toxin disrupts cell biochemistry by covalently modifying the alpha subunit of which of the following trimeric G proteins? A. Gs B. Gi C. Go D. Gq E. none of the above

A. Gs

During the UPR, which of the following misfolded protein sensors in the ER membrane signals through a cytosolic ribonuclease domain by excising an intron from a pre-existing mRNA molecule? A. IRE1 B. PERK C. ATF-6 D. all of the above E. none of the above

A. IRE1

The effect of pertussis toxin treatment on trimeric G-protein signaling is due to which of the following covalent modifications?

ADP ribosylation of the alpha subunit

A nuclear import receptor binds tightly to which of the following? A. Ran-GTP B. Ran-GAP C. Ran-GEF D. Ran-GDP

A. Ran-GTP

Signal mediated up-regulation of cell surface receptors involves the transfer of sequestered receptors from which of the following compartments? A. late endosomes B. recycling endosomes C. trans-Golgi network D. ER E. secretory vesicles

B. recycling endosomes

Which of the following transport complexes is not located on the mitochondrial inner membrane? A. TOM complex B. TIM23 complex C. TIM22 complex D. OXA complex

A. TOM complex

During the formation of the clathrin-coated vesicles, which of the following recruits the adaptin protein (AP2) to the membrane? A. a phosphoinositide B. a cargo protein C. a cargo receptor D. clathrin

A. a phosphoinositide

During delta-notch signaling, a factor is generated in the target cell that enters the nucleus and alters gene expression. Which of the following enzymes generates this factor? A. a protease B. a phosphatase C. PKA D. PKC E. phospholipase C-beta

A. a protease

What is a Rab? A. a vesicle protein that directs the vesicle to the appropriate target membrane B. a tethering protein on the target membrane that binds to the vesicle C. a vSNARE protein D. an adaptin protein E. none of the above

A. a vesicle protein that directs the vesicle to the appropriate target membrane

What is the function of SRP? A. binds to ER import signal and arrests translation B. binds to the translocation channel to begin co-translational transport C. recognizes mitochondrial import signal and unfolds the protein D. assists in nuclear import of proteins E. all of the above are functions of SRP

A. binds to ER import signal and arrests translation

Most GPCRs encoded in the human genome signal through which of the following intracellular messengers? A. cAMP B. cGMP C. calcium D. IP3 E. diacylglycerol

A. cAMP

Which of the following best describes the expected results of cholera toxin on Gs G-proteins? A. cAMP levels go up B. cAMP levels go down C. cGMP levels go up D. IP3 levels go up E. IP3 levels go down

A. cAMP levels go up

During the formation of clathrin-coated vesicles, which of the following happens first? A. cargo-bound receptors recruit adaptins B. clathrin triskelions are phosphorylated C. clathrin triskelions are de-phosphorylated D. ARP proteins bind clathirn triskelions E. dynamin is activated

A. cargo-bound receptors recruit adaptins

Which of the following statements about vesicle budding from the Golgi is FALSE? A. clathrin molecules are important for binding to and selecting cargos for transport B. adaptins interact with clathrin C. once vesicle budding occurs, clathrin molecules are released from the vesicle D. clathrin molecules act at the cytosolic surface of the Golgi membrane E. all of the above are true

A. clathrin molecules are important for binding to and selecting cargos for transport

During development of the central nervous system, cells in the neuroectoderm that have committed to differentiation into neurons signal to their neighbors by displaying which of the following proteins? A. delta B. notch C. neuroblastin D. dermulin E. none of the above

A. delta

During receptor-mediated endocytosis, the contents of clathrin-coated vesicles are initially sorted in which compartment? A. early endosomes B. late endosomes C. trans Golgi complex D. lysosomes E. none of the above

A. early endosomes

Glycoproteins that receive a mannose-6-phosphate tag during transit through the Golgi complex are packaged into vesicles and shipped to which of the following compartments? A. endosomes B. the extracellular compartment C. the cytoplasm D. two of the above E. all of the above

A. endosomes

Misfolded proteins that appear in the trans Golgi network are packaged into vesicles and delivered to which of the following compartments? A. endosomes B. the EC compartment C. the cytoplasm

B. the EC compartment

What is the function of the large intracellular loop domain of a typical G-protein coupled receptor? A. it binds to G-protein B. it activates adelylyl cyclase C. it is a protein kinase domain D. it is a ligand binding domain E. it targets the protein for degradation in the 20S proteasome

A. it binds to G-protein

Which of the following is false regarding PKA? A. it is activated by the binding of cAMP to the catalytic subunit B. it phosphorylates and activates the CREB protein C. it mediates the effects of GPCRs that signal through Gs D. it is a serine-threonine kinase E. all of the following are true about PKA

A. it is activated by the binding of cAMP to the catalytic subunit

Hydrolytic enzymes that are concentrated in the lysosome are dependent upon which of the following conditions for full activity? A. low pH B. high pH C. low calcium D. high calcium E. phase of the moon

A. low pH

Which of the following substrates is phosphorylated by the PI3 kinase? A. phosphatidylinositol 4,5 biphosphate B. phosphatidylinositol 3,4,5 triphosphate C. inositol 1,4,5 triphosphate D. all of the above E. none of the above

A. phosphatidylinositol 4,5 biphosphate

The direction of transport through the nuclear pore complex is primarily determined by which of the following? A. restriction of RAN-GEF to the nuclear compartment B. restriction of RAN-GEF to the cytoplasmic compartment C. a gradient of GTP across the nuclear envelope D. a gradient of ATP across the nuclear envelope E. restriction of RAN-GAP to the nuclear compartment

A. restriction of RAN-GEF to the nuclear compartment

Post-translational processing of secretory proteins is completed in which of the following compartments? A. secretory vesicle B. early endosome C. ER lumen D. Cis golgi network E. trans golgi network

A. secretory vesicle

Phospholipase C activation leads to the production of at least two signaling molecules, IP3 and diacylglycerol. What is the function of IP3? A. stimulates the release of calcium from the smooth ER B. recruits PKC to the plasma membrane C. recruits Akt kinase to the plasma membrane D. activates adenylyl cyclase E. none of the above

A. stimulates the release of calcium from the smooth ER

Which of the following is the calcium sensor that facilitates exocytotic release of NT at the presynaptic terminal? A. synaptotagmin B. synaptobrevin C. syntaxin D. SNAP25

A. synaptotagmin

During GPCR signaling, which protein serves as the guanine nucleotide exchange factor for the G-alpha subunit? A. the occupied GPCR B. phosphatidyl inositol C. the beta subunit D. the gamma subunit E. the beta-gamma subunit

A. the occupied GPCR

Which of the following best describes the orientation of a protein in the ER membrane that contains 3 internal hydrophobic domains, but no N-terminal hydrophobic domains? A. three transmembrane alpha helices with N-term in the cytosol B. three transmembrane alpha helices with N-term in the ER lumen C. two transmembrane alpha helices with N-term in the ER lumen D. two transmembrane alpha helices with C-term in the cytosol E. two transmembrane alpha helices with N-term and C-term on opposite sides of the ER

A. three transmembrane alpha helices with N-term in the cytosol

How is the asymmetrical distribution of phospholipids across the plasma membrane created?

ABC transporter move them between the cytosolic and luminal leaflets of the ER membrane

How is the asymmetrical distribution of phospholipids across the plasma membrane created?

ABC transporters called flippases move them between the cytosolic and luminal leaflets of the ER membrane

which of the following is false regarding N-glycosylation process?

ALL ARE TRUE N-glycosyation (Asn) begins in the ER a preformed 14 residue oligosaccharide is transferred to the amide nitrogen of an asparagine residue on the glycoprotein the first 7 sugar residues of the oligosaccharide are attached to the dolichol carries of the cytoplamic side of the ER the last 3 glucose residues must be removed prior to the incorporation of the glycoprotein into COP2 vesicles 1. a 14 residue oligosaccaride is transferred from the lipid carrier dolichol to the amide nitrogen of an ASN residue on the luminal domain of the protein 2. the last two glucose moietes are gradually removed during protein folding 3. the oligosaccharide precursor is modified in the golgi 4. in this way the pattern of glycosylation records progress through the golgi to the target compartments the point: by gradually changing the pattern of glycosylation of the glycoprotein the golgi can keep track of where its been

You have isolated a temperature sensitive yeast mutant. When maintained at the restrictive temperature, all of the yeast cells are arrested at the Metaphase-Anaphase (M-A) checkpoint due to a loss-of-function mutation of a single gene. Which of the following proteins / protein complexes is most likely responsible for the observed phenotype (i.e., arrest at M-A checkpoint)?

APC

You have isolated a temperature sensitive yeast mutant. When maintained at the restrictive temperature , all of the yeast cells are arrested at the Metaphase-Anaphase checkpoint due to a loss-of-function mutation of a signal gene. Which of the following proteins complexes is most likely responsible for the observed phenotype?

APC/C

Which of the following protein complexes can grow new actin filaments at a 70 degree angle from an existing actin filament?

ARP complexes

During movement of myosin motor proteins along filament, which of the following events results in release of the motor head from the actin filament?

ATP binding

During the movement of kinesin dimer along a microtubule, which of the following events is responsible for the "power stroke"

ATP exchange for bound ADP on the leading head

Which of the following statements regarding HSP70-type molecular chaperones is TRUE? a) ATP hydrolysis results in the binding of chaperone proteins to polar amino acids on the target protein. b) ATP exchange results in the dissociation of chaperone proteins from hydrophobic amino acids on the target protein. c) GTP hydrolysis results in the binding of chaperone proteins to polar amino acids on the target protein. d) GTP exchange results in the dissociation of chaperone proteins from hydrophobic amino acids on the target protein. e) None of the above statements are true.

ATP exchange results in the dissociation of chaperone proteins from hydrophobic amino acids on the target protein.

Which of the following statements regarding ubiquitin-mediated proteolysis is FALSE? a) Ubiquitin activation requires ATP hydrolysis b) The first ubiquitin molecule is attached to the epsilon amino group of a lysine residue on the target protein c) A chain of ubiquitin molecules directs the target protein to the 20S proteasome d) Ubiquitin is not degraded by the 20S proteasome e) All of the above are true regarding ubiquitin-mediated proteolysis

All of the above are true regarding ubiquitin-mediated proteolysis

During signaling through a G-proteins coupled receptor, GTP exchange on the alpha subunit of a trimeric G-protein complex is facilitated by binding to which of the following?

An occupied receptor

GTP exchange on the alpha subunit of a trimeric G-protein is facilitated by binding to which of the following?

An occupied receptor

Which of the following is false about N-glycosylation? A. it begins in the ER lumen B. a preformed oligosaccharide is attached to the N-term amino acid residue C. a preformed oligosaccharide is attached to the amide nitrogen of an asparagine residue D. the last two glucose residues are immediately cleaved E. all of the above are false

B. a preformed oligosaccharide is attached to the N-term amino acid residue

Which of the following is false about nicotinic Ach receptor? A. it is a heteropentameric, ligand gated ion channel B. acetylcholine binds to each of the five subunits C. the channel is permeable to sodium ions D. it was the first chemically gated ion channel to be isolated E. all of the above

B. acetylcholine binds to each of the five subunits

How is the progress of proteins processed through the Golgi complex monitored? A. by a pattern of phosphorylation B. by modifications of the N-oligosaccharide C. by a program of N-term proteolysis D. by the fold of the protein E. by the binding of chaperone proteins

B. by modifications of the N-oligosaccharide

The mis-folded protein response pathway results in biosynthesis of which of the following proteins? A. ribosomal proteins B. chaperone proteins C. the 20S proteasome D. nuclear import receptors E. none of the above

B. chaperone proteins

During the docking and fusion of transport vesicles with their target membranes, SNARE proteins form complexes that pull the vesicle toward the membrane, what kind of complex is formed? A. triskelions B. coiled coils C. coiled springs D. Rab complexes E. SNARE proteins don't form complexes

B. coiled coils

Glycosylphosphatidylinositol (GPI) anchors fix proteins on which of the following sites? A. extracellular leaflet of the plasma membrane B. cytoplasmic leaflet of the plasma membrane C. cytoplasmic leaflet of secretory vesicles D. cytoplasmic leaflet of endosomal membrane E. luminal leaflet of peroxisome membrane

B. cytoplasmic leaflet of the plasma membrane

During GPCR signaling through adenylyl cyclase, which of the following events terminates the signal process? A. reassembly of the trimeric G-protein complex B. degradation of the cAMP by PDE C. dissociation of the ligand from the GPCR D. GTP hydrolysis by the G-alpha subunit E. all of the above

B. degradation of the cAMP by PDE

Phospholipase C activation leads to the production of at least two signaling molecules, IP3 and diacylglycerol. What is the function of diacylglycerol? A. it activates receptors on the smooth ER resulting in the release of calcium into the cytoplasm B. it recruits protein kinase C to the plasma membrane C. it activates adenylyl cyclase D. it activates guanylyl cyclase

B. it recruits protein kinase C to the plasma membrane

What is the term for a receptor that indirectly activates an ion channel on the plasma membrane? A. ionotropic B. metabotropic C. pleotropic D. isotropic

B. metabotropic

During the misfolded protein response, a transcription factor is activated that drives the expression of certain proteins. Which of the following proteins is most highly expressed during the misfolded protein response? A. nuclear transport receptors B. molecular chaperones C. DNA polymerase D. SNARE proteins E. ubiquitin

B. molecular chaperones

During signaling though a trimeric G-protein, how is the action of the beta-gamma complex terminated?

Binding to the GDP-bound form of the alpha subunit

During signaling through a trimeric G-protein, how is the action of the beta-gamma complex terminated?

Binding to the GDP-bound form of the alpha subunit

How does cytochrome C escape mitochondria to promote apoptosis?

By leaving through channels in the outer membrane formed by BH123 proteins

How might the Golgi complex monitor the 'progress" of the post translation protein processing?

By modification of the N-oligosaccharide

How does the anti-apoptotic protein, Bcl2, prevent apoptosis?

By preventing the aggression of "BH123" proteins

How does cytochrome C promote apoptosis via the intrinsic pathway

By promoting the aggregation of initiator procaspases

Which of the following species was chosen as a model organism for the study of invertebrate development?

Caenorhabditis elegans

Which of the following proteins serves as that plus (+) end capping proteins of actin filaments in the sarcomere?

Cap Z

Which of the following proteins serves as the plus (+) end capping protein of actin filaments in striated myocytes?

CapZ

5 Essential Characteristics of All Living Cells?

Capable of protein synthesis Capable of autonomous replication Contains nucleic acid that encodes at least one complete copy of a genome

Which of the following monomeric GTPases provides the energy for release of newly formed vesicles from the source memebrane?

Dynamin

What provides the force that drive chromosomal segregation during anaphase A?

Catastrophic fraying of kinetochore microtubules

Which of the following is phosphorylated by S-Cdk to initiate DNA synthesis during S-phase?

Cdc6

Most transport vesicles destined for the endosomal systems are formed by which of the following coat proteins?

Clathrin

When the cyclic AMP-dependent protein kinase (PKA) enters the nucleus, it phosphorylates which of the following transcription factors?

Cyclic AMP response element binding (CREB) protein

Failure of anaphase promoting complex (APC) to ubiquinate this protein would result in arrest of cell cycle at anaphase which of the following is this proteins?

Cyclin B

Which is the function of the synaptic protein, synaptobrevin

IT is the V-SNARE on the synaptic vesicle

During nuclear import, what happens IMMEDIATELY AFTER the binding of RAN-GTP to the nuclear import receptor (NIR)?

Dissociation of a cargo protein from the NIR

During movement of myosin protein along actin filament, which of the following events results in "power stroke"?

Dissociation on Pi

Which of the following species was chosen as a model organism for genetic analysis due, in part, to unusually large "polytene" chromosomes?

Drosophila melanogaster

The ability of vesicles to fuse with the target membrane is maintained at the expense of ATP hydrolysis. When does ATP hydrolysis occur?

During dissociation of SNARE complexes

The ability of vesicles to fuse with the target membrane is maintained at the expense of ATP hydrolysis. When does ATP hydrolysis occur?

During dissociation of SNARE proteins

Which of the following GTPases is responsible for the release of clathrin-coated vesicles from the plasma membrane?

Dynamin

During receptor-mediated endocytosis, clathrin-coated vesicles sort directly to which of the following compartments?

Early endosomes

Which of the following best describes a structural feature through which a misfolded soluble proteins might be recognized by proteins surveillance machinery of the cell?

Exposed non-polar amino side chains in the cytosol

which amino acid could identify as a secretory protein?

H2N-MET-MET-LEU-VAL-ILE-ILE-GLY-ALA-VAL-LEU

Which of the following amino acid sequence could identify a secretory protein

H2N-Met-Met-Leu-Val-Ile-Ile-Gly-Ala-Val-Leu

During protein synthesis, secondary structural elements fold first. These are primarily stabilized by which of the following non-covalent bonds?

Hydrogen bonds between elements of the peptide backbone

During endosomal maturation, the luminal concentration of which of the following ions gradually increase, with the highest concentration occurring in lysosomes?

Hydrogen ions

During endosomal maturation, the luminal concentration of which of the following ions gradually increases, with the highest concentration occurring in lysosomes?

Hydrogen ions

The signal recognition particle (SRP) binds to the ER sorting signal on the nascent polypeptide and arrests (stops) translation. When does translation resume?

Immediately after binding of the sorting sequence to the ER translocator

The signal recognition particle binds to the ER sorting signal of the nascent polypeptide and arrests translation. When does translation resume?

Immediately after binding of the sorting sequence to the ER translocator

Protein component of the ESCRT system are responsible for the formation of which of the following vesicles

Intraluminal vesicles

Protein components of the ESCRT system are responsible for the formation of which of the following vesicles?

Intraluminal vesicles

During processing in the Golgi complex, which of the following proteins becomes labeled with a mannose-6-phosphate tag?

Lysosomal acid hydrolases

Which of the following is phosphorylated by MAP kinase kinase kinase (Raf)?

MAP kinase kinase

MPF refers to the substance present in the cytosol of Xenopus oocytes that is capable of driving multiple cycle of M phase and and S phase in vitro. what is MPF?

Maturation Promoting Factor

MPF refers to the substance(s) present in the cytosol of Xenopus oocytes that is capable of driving multiple cycles of M phase and S phase in vitro. What is MPF?

Maturation Promoting Factor

Which of the following ion channel is responsible for sound detection in the cochlea?

Mechanically-gated sodium channels

which of the amino acid sequence does NOT mark the ASP residue for N-type-glycosylation?

N-A-P these DO NAS NET NES NIT ****TARGET AA SEQUENCE N(X any amino acid) S/T

Which of the following is True regarding the N-glycosylation process?

Proteins with a Pleckstrin Homology domain can be recruited to the plasma by binding to a phosphorylated form of which of the following phospholipids

Phosphatidyl inositol

The AKT kinase is recruited to the plasma membrane by which of the following membrane associated molecules?

Phosphatidyl inositol 3,4,5 triphosphate

Complete the following sentence "During clathrin-coated vesicle formation, adaptin protein 2 (AP2) complexes are activated by specific ..."

Phosphoinositides

During the transport cycle of the calcium ATPase, which of the following events causes the conformation change that enables transports of 2 calcium ions of the cytosol?

Phosphorylation of the an aspartate residue

T/F When an occupied nuclear import receptor binds RAN-GTP, cargo protein is released

TRUE

Which of the following monomeric GTPases directs a vesicle to the appropriate target membrane

Rab

which of the following monomeric GTPase directs a vesicle to the appropriate target membrane?

Rab -rab gtpases direct vesicle to target membrane

As a vesicle approaches the target membrane, tethering proteins bind to which of the following?

Rab-GTP proteins on the vesicle

as a vesicle approaches the target membrane, tethering proteins bind to ..?

Rab-GTP proteins on the vesicle -Rab-GTPase direct vesicles to the target membrane - dissociation of coat and adaptor proteins from the vesicle is necessary to expose cytosolic domains of vesicle proteins that mediate delivery to Rab-GTPases and fusion with v-SNARES the target membrane

As a vesicle approaches the target membrane, tethering proteins bind to which of the following?

Ran-GTP proteins on the vesicle

Mitogens promote entry into cell cycle by inactivating which of the following proteins?

What is/are Caveolae?

Small endocytic vesicles containing membrane proteins and sphingomyelin

What is/are caveolae?

Small endocytic vesicles rich in membrane proteins and sphingomyelin

Growth factor signals through the AKT kinase, resulting in the phosphorylation and activation of which of the following

TOR

Is the following sentence TRUE or FALSE? "Immediately after release of coated vesicles from the source membrane, the coat proteins dissociate."

TRUE

Is the following statement TRUE or FALSE? "Cytosolic domains of plasma membrane proteins remain in the cytosol throughout transport through the Golgi."

TRUE

Is the following statement TRUE or FALSE? "In some cells, activation of phospholipase C-beta causes waves of Ca2+ release to spread along the endoplasmic reticulum."

TRUE

Is the following statement TRUE or FALSE? "Lamellipodia are autonomous motile structures driven by actin polymerization."

TRUE

T/F Cytosolic domains of plasma membrane proteins remain in the cytosol throughout transport through the Golgi

TRUE

T/F In some cells, activation of phospholipase C-beta causes waves of Ca2+ release to spread along the ER.

TRUE

Which of the following occur immediately after a nuclear export receptor bind to RAN-GTP?

The cargo proteins bind with high affinity

What is a glycocalyx?

The thick layer of glycosylation on the extracellular leaflet of the plasma membrane of certain cells

Ultimately, the destination for vesicles containing mature proteins is determined in which of the following comperments?

Trans Golgi network

Within the Golgi complex, where would you expect to find mannose-6-phosphate receptor?

Trans-Golgi network

Which of the following peptide sequences is composed entirely of non-polar amino acids?

VIAL

Cyclin B (M-cyclin) levels rise throughout S-phase to peak early in G2-phase. However, M-phase does not begin until after G2-phase. Which of the following enzymes prevents premature entry into M-phase?

Wee1

Which of the following kinases is responsible for phosphorylation and inactivation of M-Cdk?

Wee1

Which of the following proteins is responsible for phosphorylation and inactivation of M-cdk?

Wee1

When is a misfolded protein considered to be a "prion"

When the protein transmits disease to other organisms

Which of the following animals was chosen as a model species for the investigation of vertebrate development?

Xenopus Laevis

Potassium leak channels are 10,000 fold more permeable to potassium ions. What is the structural basis for the ion selectivity of potassium leak channels?

a series of carbonyl oxygen atoms along the selectivity

What is the structural basis for the ion selectivity of the voltage gated potassium channel?

a series of carbonyl oxygen atoms along the selectivity channel

The Get3 ATPase facilitate post-translational insertion of certain proteins into the ER membrane. Which of following is the common feature of proteins that rely on the Get3 ATPase for insertion into the ER membrane?

a single transmembrane domain at the C-terminus

which is the common feature of proteins that rely on Get3 ATPase for insertion into the ER membrane

a single transmembrane domain at the C-terminus -get3 is only for proteins that only have hydrophobic domain integral membrane at the c terminus (this system cant use sec 61)

At the leading edge of the motile cell. which of the following events provides the force that drives the lamellipodium forward?

actin polymerization

Which of the following events propels the lamellipodium of a motile cell forward?

actin polymerization

what describes a molecule that mimics the affect of a natural ligand by binding to its cognate receptor?

agonist -things that BLOCK = antagonist

During the formation of a focal adhesion adherens junction, which of the following components of the junctional complex is unfolded to reveal vinculin binding sites and enabling the recruitment of actin filaments?

alpha catenin

during signaling through a G protein couples receptor, GTP exchange on the alpha subunit of a trimeric G protein complex is facilitated by binding to which of the following?

an occupied receptor 1. receptor ligand binding stabilizes the active conformation of the receptor 2. increases affinity for GDP bound trimeric G protein complex 3. OCCUPIED RECEPTOR binds tightly to the g protein 4.active receptor conformation acts as a GEF which facilitates exchange of GDP for GTP on alpha-subunit of trimeric G protein 5. binding alters the conformation of the alpha subunit 6.activating both a subunit and b-y complex 7. a and b-y can separate and signal diff pathways

In a motile cell, where would you expect to find most of the ARP complex?

at the leading edge of the cell

Which of the following kinases is responsible for preventing the assembly of Ndc80 complexes on kinetochore microtubules?

aurora-B kinase

Which of the following kinases is responsible for preventing the assembly of Ndc80 complexes on kinetochore microtubules?

aurora-B kinases

10. Is the following statement TRUE or FALSE? "When an occupied nuclear import receptor binds RAN-GTP, the cargo protein is released." a) the above statement is TRUE b) the above statement is FALSE

15. An extracellular messenger molecule that increases intracellular calcium levels in target cells, and is NOT blocked bypertussis toxin, probably signals through which of the following trimeric G-proteins? a) Go d) Gi b) Gq e) Gt c) Gs

Which of the following organelles is responsible for the synthesis of new membrane for components of the endomembrane system?

endoplasmic reticulum

Which of the following is one way in which a misfolded protein might be recognized by the protein surveillance machinery of the cell?

exposed non-polar amino acid side chains

At the plasma membrane, which of the following phospholipids is found exclusively on the intracellular [SHOULD HAVE SAID "extracellular"] leaflet?

glycolipids

Which of the following phospholipids is found exclusively on the extracellular leaflet of the plasma membrane?

glycolipids

What is the role of the troponin complex in striated muscle contraction?

it binds calcium and moves tropomyosin off myosin binding sites

Lysozyme is an antibacterial enzyme found in saliva. Which of the following statement about lysozyme is true?

it binds to 6 sugar residue of the substrate it employs coordinated acid base catalysis Binding of the substrate results in distortion of the "D" rings

Which of the following is FALSE regarding collagen?

it is a dimeric, coiled coil.

Which of the following statements is FALSE regarding microtubules?

microtubules undergo "catastrophe", during which, protofilaments fray at the minus (-) end

The active site of most enzymes is primarily composed of which of the following?

non-adjacent polar amino acids

The actives site of most enzymes is primarily composed of which of the following?

non-adjacent, polar/Charged amino acids

Which of the following is an intermediate filament that is found in ALL eukaryotic cells?

nuclear lamins

Which of the following events occurs immediately after GTP hydrolysis by elongation factor Tu (EF-Tu).

release of the aminoacyl t-RNA

the directionality of transport across the nuclear envelope via the nuclear pore complex is due to ?

restriction of Ran -Gef to the nuclear compartment - ran- GEF is in nucleus and attached to chromatin -ran-GAP is in cytosol - restriction of ran-GAP and ran-GEF to opposite sides of the nuclear envelope ensures directional transport -Ran GTP binds to NTR and determines the direction of transport across the NPC. -ran GDP = CYTOSOL -ran GTP = NUCLEAR signal sequence : PRO-PRO-LYs lys lys arg lys

During receptor mediated endocytosis of LDL particles, what happens to the LDL receptor?

retuned to the plasma membrane -cholesterol circulates and is delivered to cells in esterfied form in low density lipoproteins (LDL) - these bind to LDL receptors on the surface of target cells and enter the cell by receptor mediated endocytosis

What is the smallest contractile unit of a striated myocyte (muscle cell)?

sarcomere

What is the term for the smallest contractile unit of skeletal muscle

sarcomere

What is the source of the calcium that permits contraction of skeletal muscle?

sarcoplasmic reticulum

Which of the following microscopic techniques provides the highest resolution images of the surface morphology of a specimen?

scanning electron microscopy

Which mode of representation of the tertiary structure of a protein provides the most information about the location and orientation of secondary structural elements?

schematic / ribbon model

At The metaphase-anaphase checkpoint, anaphase promoting complex ubiquinated which of the following proteins to release separase from inhibition

securin

which of the following phospholipids is NOT a phosphoglycerol?

sphingomyelin

How is sphingomyelin different from membrane phospholipids like phosphatidylcholine?

sphingomyelin is not a phosphoglyceride

Which of the following is a microtubules organizing center

spindle pole basal body centrosome spindle pole

what is the function of IP3

stimulates release of Ca from smooth ER from google " mobilize calcium from storage organelles and to regulate cell proliferation " '"in smooth muscle cells an increase in cytoplasmic Ca results in contraction"

structure comprised mostly of actin filaments?

stress fiber c) lamellipodium d) contractile ring e) microvilli

Which of the following is an actin rich structure

stress fibers the lamellipodium microvilli

how does calcium - dependent ER chaperone protein, calnexin, recognize and bind proteins that may be misfolded

the oligosaccarrhide on the asparagine residue of the protein has one terminal glucose moiety - will only bind of there is a glucose mannose at the tip - contributes to proper folding, then if successful to will chop off last glucose moiety then goes to er lumen then golgi

How does the calcium-dependent ER chaperone, Calnexin, recognize and bind proteins that may be misfolded?

the oligosaccharide on an asparagine residue of the protein has one terminal glucose moiety

In general, the nature of the cellular response to a chemical messenger is determined primarily by which of the following

the receptive apparatus of the cell

in general, the nature of the cellular response to a chemical messenger is determined by

the receptive apparatus of the cell -same signal but different responses -response to a messenger depends on cell signaling machinery ; same messenger (acetylcholine)-different message

The spatial resolution of optical microscopy is primarily a function of which of the following?

the wavelength of the light

Which of the following statements is FALSE regarding the immunoglobulin molecule? a) it is a heterotetramer composed of two light chains and two heavy chains b) there are four antigen binding domains c) the antigen binding domain(s) include elements of both the light and heavy chains d) the light and heavy chains are stabilized by disulfide bonds e) all of the above are TRUE regarding the immunoglobulin domain

there are four antigen binding domains

Which of the following statements about secretion is TRUE? A. the membrane of a secretory vesicle will fuse with the plasma membrane when it discharges its contents to the cell's exterior B. vesicles for regulated exocytosis will not bud off the TGN until the appropriate signal has been received from the cell C. the signal sequences of proteins destined for constitutive exocytosis ensure their packaging into the correct vesicles D. proteins destined for constitutive exocytosis aggregate as a result of the acidic pH of the TGN E. all of the above

A. the membrane of a secretory vesicle will fuse with the plasma membrane when it discharges its contents to the cell's exterior

Which of the following signal sequences identifies a soluble protein for return to the ER lumen? A. --Leu-Asp-Asp-Leu-COOH B. --Lys-Asp-Glu-Leu-COOH C. --Leu-Glu-Asp-Lys-COOH D. --Lys-Asp-Asp-Leu-COOH

B. --Lys-Asp-Glu-Leu-COOH

During receptor mediated endocytosis of LDL particles, what happens to the LDL receptor? A. It is delivered to the trans-Golgi network B. It is usually returned to the plasma membrane C. It is ubiquinated, and degraded in the 20S proteosome D. It is always degraded by acid proteases in the endolysosome

B. It is usually returned to the plasma membrane

Your friend has just joined a lab that studies vesicle budding from the Golgi and has been given a cell line that does not form mature vesicles. He wants to start designing some experiments but wasn't listening carefully when he was told about the molecular defect of this cell line. He's too embarrassed to ask and comes to you for help. He does recall that this cell line forms coated pits but vesicle budding and the removal of coat proteins don't happen. Which of the following proteins might be lacking in this cell line? A. Rab B. dynamin C. adaptin D. clathrin E. SNARE

B. dynamin

During receptor-mediated endocytosis, which event recruits adaptins to the membrane? A. phosphorylation of membrane proteins B. formation of receptor-ligand complexes C. changes in phospholipid asymmetry D. GTP hydrolysis by the dynamin complex E. binding of clathrin triskelions

B. formation of receptor-ligand complexes

Ca2+ pumps in the plasma membrane and endoplasmic reticulum are important for _____________. A. maintaining osmotic balance B. preventing Ca2+ from altering the activity of molecules in the cytosol C. providing enzymes in the endoplasmic reticulum with Ca2+ ions that are necessary for their catalytic activity D. maintaining a negative membrane potential

B. preventing Ca2+ from altering the activity of molecules in the cytosol

Which of the following statements about the unfolded proteins response (UPR) is false? A. activation of the UPR results in the production of more ER membrane B. activation of the UPR results in the production of more chaperone proteins C. activation of the UPR occurs when receptors in the cytoplasm sense misfolded proteins D. activation of the UPR results in the cytoplasmic activation of gene regulatory proteins E. all of the above are true

C. activation of the UPR occurs when receptors in the cytoplasm sense misfolded proteins

The sorting sequence -- P-P-R-R-R-K-R-V - would direct a soluble protein to which of the following compartments? A. Mitochondrion B. Chloroplast C. Nucleus D. Peroxisome E. Endoplasmic Reticulum

C. Nucleus

Which of the following statements is true? A. the signal sequences on mitochondrial proteins are usually at the C-terminus B. most mitochondrial proteins are not imported from the cytosol , but are synthesized inside the mitochondrion C. chaperone proteins in mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes D. mitchochondrial proteins cross the membrane in their native folded state E. none of the above are true

C. chaperone proteins in mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes

In the trans-Golgi network, which of the following coat proteins is/are responsible for the formation of vesicles containing lysosomal enzymes? A. COP proteins B. adaptins C. clathrin D. Rab GTPase E. vSNAREs

C. clathrin

Which of the following coat proteins is/are responsible for the formation of the endocytic vesicles at the plasma membrane? A. COP proteins B. adaptins C. clathrin D. Rab GTPase E. vSNAREs

C. clathrin

Your friend who works in a biotechnology company, has discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport? A. nuclear transport receptors would be unable to bind cargo B. nuclear transport receptors would be unable to enter the nucleus C. nuclear transport receptors would be unable to release their cargo in the nucleus D. nuclear transport receptors would interact irreversibly with the nuclear pore fibrils E. nuclear transport receptors would be targeted for destruction in the proteasome

C. nuclear transport receptors would be unable to release their cargo in the nucleus

What do Rab proteins do? A. they are molecular motor proteins B. they facilitate vesicular membrane fusion C. they are recognized by tethering proteins on target membranes D. they bind to t-SNAREs E. they recruit coating proteins

C. they are recognized by tethering proteins on target membranes

What event in the SNARE complex cycle requires the hydrolysis of ATP? A. binding of v-SNAREs to t-SNAREs B. binding of Rab GTPases to the tethering proteins C. binding of Rab GTPases to the SNARE complex D. dissociation of the SNARE complex E. ATP hydrolysis is not involved in the SNARE complex cycle

D. dissociation of the SNARE complex

An accumulation of misfolded proteins in the ER lumen triggers the "Unfolded Protein Response". One component of this process is the IRE1 mechanism, during which IRE1 sensor protein undergoes autophosphorylation resulting in the activation of its ribonuclease domain. As a consequence, a single exon is removed from a pre-mRNA present in the cytosol, and the resultant mRNA is translated. Which of the following best describes the protein that is encoded by this mRNA? A. it is a phosphatase B. it is a kinase C. it is a molecular chaperone D. it is a transcription factor

D. it is a transcription factor

A membrane protein whose primary structure includes an N-terminal ER signal sequence AND 3 internal runs of 8 or more consecutive non-polar amino acids will undergo co-translational transport at the ER. Which of the following best describes the orientation of this membrane protein in the ER membrane. A. Three transmembrane domains with the C-terminal in the ER lumen B. Three transmembrane domains with the N-terminal in the cytosol C. Three transmembrane domains with the C and N terminals on the same side of the ER membrane D. Four transmembrane domains with the N-terminal in the ER lumen E. Three transmembrane domains with the C- and N-terminals on opposite sides of the ER membrane

E. Three transmembrane domains with the C- and N-terminals on opposite sides of the ER membrane

Which of the following statements is false regarding proteins transport into the mitochondria? A. the protein must have an N-terminal mitochondrial signal sequence B. the protein is transported in the unfolded state C. refolding of the protein in the matrix requires ATP hydrolysis D. transport is partially powered by the electrochemical gradient across the inner mitochondrial membrane E. all of the above are true

E. all of the above are true

Which of the following best describes the orientation of a protein in the ER membrane that contains an N-terminal ER signal sequence and two internal hydrophobic domains? A. three transmembrane alpha helices with N-term in the ER lumen B. three transmembrane alpha helices with N-term in the cytosol C. two transmembrane alpha helices with N-term in the ER lumen and the C-term in the cytosol D. two transmembrane alpha helices with C-term in the ER lumen and the D-term in the cytosol E. two transmembrane alpha helices with N-term and the C-term on same side of ER membrane

E. two transmembrane alpha helices with N-term and the C-term on same side of ER membrane

14. Phospholipase Cbeta activation leads to the production of (at least) two signaling molecules inositol 1,4,5-trisphosphate (IP3) and diacylglycerol. What is the function of IP3? a) it stimulates the release of calcium from the smooth ER b) it recruits protein kinase C to the plasma membrane c) it recruits Akt kinase to the plasma membrane d) it activates adenylyl cyclase e) none of the above

38. Prior to vesicle formation, how are adaptins recruited to the appropriate membrane. a) by specific phosphoinositides on the cytosolic surface b) by the pH of the compartment c) by the amount of phosphatidylserine on the membrane d) by the assembly of cargo receptors e) none of the above

47. What is the function of the signal recognition particle (SRP)? a) binds to ER import signal and arrests translation b) binds to the translocation channel to begin co-translational transport c) recognizes mitochondrial import signal and unfolds the protein d) assists in nuclear import of proteins e) all of the above are functions of the SRP

52. How are receptor tyrosine kinases (RTKs) activated? a) by ligand-mediated dimerization b) by binding to a G-protein c) by PKA-mediated phosphorylation d) by Akt-mediated phosphorylation e) none of the above

55. Formation of PI(3,4,5)P3 by PI3 kinase results in the recruitment of proteins that possess which of the following? a) pleckstrin homology (PH) domain b) Src Homology 2 (SH2) domain c) Src Homology 3 (SH3) domain d) PTB domain e) kinase domain

Choose from the following amino acid sequences as you answer questions 56-58. a) NYLSCKDEL b) APPRRRKRV c) MLAVALVIA d) LRNSIRFFLK e) GATALACAT 57. Which of the above C-terminal sequences could identify proteins for return from the cis-Golgi

26. Which of the following is the largest family of cell signaling proteins encoded in the human genome? a) enzyme coupled receptors b) G-protein coupled receptors c) nuclear receptors d) small GTPases e) ion channels

27. How is the progress of proteins processed through the Golgi complex monitored? a) by a pattern of phosphorylation b) by modifications of the N-oligosaccharide c) by a program of N-terminal proteolysis d) by the fold of the protein e) by the binding of chaperone proteins

31. How does the Akt kinase promote cell survival? a) by phosphorylating and activating the BAD protein b) by phosphorylating and inactivating the BAD protein c) by dephosphorylating and inactivating the BAD protein d) by phosphorylating and activating the Bcl2 protein e) by dephosphorylating and activating the Bcl2 protein

34. During LDL-receptor mediated endocytosis, clathrin-formed vesicles containing the LDL particle-receptor complexes fuse with sorting endosomes. What happens to the LDL receptors? a) they accumulate in the cytosol b) they are returned to the plasma membrane c) they are sent to the Golgi complex for repair d) they are degraded in lysosomes e) depends on the pattern of glycolysis

1. During co-translational transport, which of the following events interrupts translation of the nascent polypeptide? a) emergence of the ER signal sequence from the ribosome b) binding of the signal recognition particle (SRP) to the ER signal sequence on the nascent polypeptide. c) binding of the SRP near the "A" site of the ribosome d) binding of the SRP to the SRP receptor e) binding of the ER signal sequence to the stop-transfer site on the translocon

39. In the trans-Golgi network, pro-enzyme hydrolases destined for late endosomes are identified by which of the following features? a) an endosomal signal sequence b) a specific pattern of phosphorylation c) a mannose-6-phosphate moiety on the oligosaccharide d) covalent lipid tags e) it is not known

4. How does the calcium-dependent ER chaperone, Calnexin, recognize and bind proteins that may be misfolded? a) the proteins have exposed polar amino acids b) the proteins have exposed non-polar amino acids c) a glycosylated asparagine residue on the protein has a single terminal glucose moiety d) a glycosylated asparagine residue on the protein has no glucose moieties e) none of the above

42. What do ESCRT protein complexes do? a) they are transcription factors b) they escort proteins across the plasma membrane c) they form intraluminal vesicles in endosomes d) they regulate calcium efflux from the smooth ER e) none of the above

33. How is vesicular fusion powered? a) GTP hydrolysis drives the formation of SNARE complexes b) ATP hydrolysis drives the formation of SNARE complexes c) GTP hydrolysis drives the dissociation of SNARE complexes d) ATP hydrolysis drives the dissociation of SNARE complexes e) None of the above

49. When a differentiating cell displays the Delta ligand, adjacent cells that express the Notch receptor do which of the following. a) they divide b) they do not divide c) they become neurons d) they do not become neurons e) they deeply regret it

8. In the auditory system, "hair cells" are depolarized during activation of which of the following ion channels? a) ungated cation channels b) ligand-gated cation channels c) ligand-gated anion channels d) mechanically-gated cation channels e) mechanically-gated anion channels

13. During embryonic development, how does the Notch receptor signal that it has bound a Delta ligand? a) by activating a tyrosine kinase b) by increasing cyclic AMP c) by increasing cyclic GMP d) by activating PI3 kinase e) by releasing a proteolytic fragment of the receptor into the cytosol

16. The Ras GTPase participates in which of the following signaling pathways? a) mTOR pathway d) phospholipase Cb b) PI3 kinase pathway e) MAP kinase pathway c) JAK kinase pathway

32. Which of the following is FALSE regarding transport of proteins into the mitochondria. a) the proteins must display an N-terminal mitochondrial signal sequence (NTMSS) b) the protein must be delivered in the unfolded state c) the protein binds via its NTMSS to a receptor component of the TOM complex d) after TOM and TIM align, the protein passes across both membranes into the matric e) the process is powered entirely by the pH gradient across the inner membrane

35. Which of the following is/are TRUE regarding the role of the Rab GTPase in vesicular transport? a) It becomes associated with the source membrane prior to vesicle formation b) It identifies the target compartment of the vesicle c) it directs the transport machinery to deliver the vesicle to the target compartment d) It binds to tethering proteins on the surface of the target compartment e) all of the above is TRUE regarding Rab proteins

41. During endosomal maturation, there is a gradual decline in which of the following characteristics? a) the size of the endosome b) the density of the endosome c) the calcium concentration of the endosome d) the number of intralumenal vesicles e) the pH of the endosome

6. Photoisomerization of 11-cis retinal activates rhodopsin, which, in turn, activates the trimeric G-protein, Gt (transducin). Which of the following membrane associated enzymes is activated by Gt? a) adenylyl cyclase d) cAMP phosphodiesterase b) guanylyl cyclase e) cGMP phosphodiesterase c) phospholipase Cbeta

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