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69 Cards in this Set
- Front
- Back
- 3rd side (hint)
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The substance in the cytoplasm of M-phase cells that promotes mitosis in cell-free extracts of Xenopus oocytes was originally called
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Maturation Promoting Factor
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MPF activity is attributed to what protein
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cyclin dependent kinase 1 (Cdk1)
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In rapidly dividing cells, MPF activity was observed to oscillate, with peak levels occurring at the G2 – M transition. The oscillatory component of the MPF complex was later shown to be which of the following proteins?
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cyclin B
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Responsible for the phosphorylation of M-Cdk at the inhibitory site?
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Wee1 kinase
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The SMC protein complexes that gather and organize DNA strands into chromosomes are called
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condensins
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A temperature sensitive cdc mutant yeast strain possesses a loss-of-function mutation of cyclin B. At the restrictive temperature, cell cycle arrest will occur at what
control point? |
G2 – M checkpoint
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Breakdown of the nuclear envelop occurs during which phase of mitosis?
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prometaphase
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A loss-of-function mutation of the p53 gene would result in …
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decreased p21 expression leading to unregulated entry into S phase
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Phosphorylation of the Rb protein by G1-Cdk promotes entry into S phase by …
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releasing transcription factor E2F resulting in biosynthesis of S phase proteins
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Which of the following is NOT required for the complete activation of M-Cdk?
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a. binding of cyclin B
b. activation of Cdc25 c. phosphorylation of M-Cdk at the stimulatory site d. dephosphorylation of M-Cdk at the inhibitory site e. all of the above are required for full activation of M-Cdk |
all of the above are required for full activation of M-Cdk
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The term "interphase" refers to which of the following phase(s) of the cell cycle.
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a. G1 phase + S phase + G2 phase
b. G2 phase + M phase c. G1 phase + S-phase d. S-phase + G2 phase e. only G1 phase |
G1 phase + S phase + G2 phase
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Anaphase promoting complex (APC) is (a)
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ubiquitin ligase
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During M phase, anaphase promoting complex (APC) is activated by ...
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binding of cdc20
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Caspases are ...
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proteases
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How do survival factors prevent apoptosis?
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induction of Bcl-2 protein
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How does cytochrome C initiate apoptosis?
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it promotes the aggregation of initiator procaspases
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During apoptosis, how does cytochrome C get out of the mitochondrion?
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it leaves through channels formed by BH123 proteins
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Most procaspases are activated by ...
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other caspases
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Which of the following cell adhesion proteins (CAMs) is NOT a component of cell-cell junctions?
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a. selectins
b. integrins c. cadherins d. N-CAMs e. I-CAMs |
integrins
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Which of the following CAMs are components of adherens junctions and desmosomes?
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a. selectins
b. integrins c. cadherins d. N-CAMs e. I-CAMs |
cadherins
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Which of the following CAMs are components of focal adhesions and hemidesmosomes?
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a. selectins
b. integrins c. caherins d. N-CAMs e. I-CAMs |
integrins
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Which of the following is false regarding collagens?
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a. subunits are encoded by at least 20 genes
b. they are assembled into fibers in the extracellular space c. they are the most abundant proteins in the animal kingdom d. they are formed from two alpha helical proteins bound in a coiled-coil e. all of the above are true regarding collagen |
they are formed from two alpha helical proteins bound in a coiled-coil
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Which of the following is false regarding glycosaminoglycans ?
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a. they are components of proteoglycans
b. they are large, highly branched polysaccharides c. most are rich in N-acetylglucosamine d. they are abundant in the extracellular space e. all of the above are true regarding glycosaminoglycans |
they are large, highly branched polysaccharides
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Which of the following cell junctions does NOT include a cytoskeletal component?
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a. tight junctions
b. adherens junctions c. desmosomes d. hemidesmosomes e. all cell junctions include cytoskeletal components |
tight junctions
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Which of the following is false regarding cadherins?
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a. they form homophilic interactions
b. binding affinity is increased by high extracellular calcium concentration c. members of the catenin protein family link them to cytoskeletal proteins d. they exclusively form cell-cell junctions e. all of the above are true regarding cadherins |
all of the above are true regarding cadherins
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What is the ultimate fate of apoptotic cells?
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they are consumed by macrophages
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Which of the following proteins is NOT phosphorylated by M-Cdk?
a. cdc25 b. cohesins c. separase d. lamins e. all of the proteins listed above are phosphorylated by M-Cdk |
a. cdc25
b. cohesins c. separase d. lamins e. all of the proteins listed above are phosphorylated by M-Cdk |
*cohesins
*separase |
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What is p21?
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Cdk inhibitor
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S-Cdk complex promotes DNA replication by phosphorylating which of the following?
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a. M-Cdk
b. cdc6 c. origin of replication complex d. p21 e. none of the above |
cdc6
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At the anaphase checkpoint, which of the following events must occur for mitosis to
proceed? |
a. inactivation of Rb
b. dephosphorylation of cdc25 c. ubiquination of cyclin B by anaphase promoting complex (APC) d. phosphorylation of M-Cdk e. none of the above |
ubiquination of cyclin B by anaphase promoting complex (APC)
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Which event immediately precedes chromosomal segregation?
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proteolytic cleavage of cohesins by separase
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During anaphase, the forces that drive movement of chromatids toward opposite spindle poles include all of the following except …
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a. plus end depolymerization of kinetochore microtubules
b. plus end directed kinesin motors acting on interpolar microtubules c. minus end directed dynein motors acting on aster microtubules d. all of the above provide the forces that drive chromosomal segregation e. none of the above provide the forces that drive chromosomal segregation |
all of the above provide the forces that drive chromosomal segregation
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During cytokinesis, the orientation of the contractile ring is primarily determined by the
location of the … |
asters
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In early anaphase, APC is activated by cdc20. During G1, when cdc20 is depleted, APC activity is maintained by which of the following proteins?
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a. Rb
b. Cdh1 c. p21 d. G1-Cdk e. G1-S Cdk |
Cdh1
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Constriction of the contractile ring during cytokinesis is driven by …
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myosin II
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Apoptosis can be induced by …
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-pro-caspase activation
-expression of certain Bcl-2 genes -suppression of certain Bcl-2 genes -release of cytochrome C from mitochondria |
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The BH123 proteins Bax & Bak promote apoptosis by …
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aggregating to form channels in the mitochondrial outer membrane
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The anti-apoptotic protein, Bcl2, prevents apoptosis by …
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preventing the aggregation of Bax & Bak
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Which of the following is false regarding gap junctions?
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a. they are formed by proteins called connexins
b. eight protein subunits form a single connexon hemichannel c. connexon hemichannels on adjacent cells associate to form the functional gap junction d. calcium and small metabolites can pass through gap junctions e. all of the above are true regarding gap junctions |
eight protein subunits form a single connexon hemichannel
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Which of the following cell-cell junctions is formed by cell adhesion molecules that are
associated with intermediate filaments? |
a. tight junctions
b. adherens junctions c. desmosomes d. hemidesmosomes e. gap junctions |
desmosomes
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Which of the following is false regarding integrins
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a. they form heterdimers composed of one α and one β subunit
b. they are capable of signaling both ways c. they only form cell-matrix junctions d. they are recruited and activated by talin dimers e. all of the above are true regarding integrins |
all of the above are true regarding integrins
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Which of the following is true about hemidesomsomes
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a. α5β1 integrins binds to the IKVAV motif on laminin
b. α6β4 integrins bind to the IKVAV motif on laminin c. α6β4 integrins bind to the RGD motif on laminin d. α6β4 integrins bind to the RGD motif on fibronectin e. none of the above are true about hemidesmosomes |
α6β4 integrins bind to the IKVAV motif on laminin
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Which of the following is true about the proteins, claudin and occludin?
a. they are classical cadherins that form tight junctions through homophilic interactions b. they are classical cadherins that form tight junctions through heterophilic interactions c. they are non-classical cadherins that form tight junctions through homophilic interactions d. they are non-classical cadherins that form tight junctions through heterophilic interactions e. none of the above are true about claudin and occludin |
a. they are classical cadherins that form tight junctions through homophilic interactions
b. they are classical cadherins that form tight junctions through heterophilic interactions c. they are non-classical cadherins that form tight junctions through homophilic interactions d. they are non-classical cadherins that form tight junctions through heterophilic interactions e. none of the above are true about claudin and occludin |
they are non-classical cadherins that form tight junctions through homophilic interactions
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Which of the following cell-cell junctions is formed by cell adhesion molecules that are associated with actin filaments?
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a. tight junctions
b. adherens junctions c. desmosomes d. hemidesmosomes e. gap junctions |
adherens junctions
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What is the Philadelphia Chromosome?
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a diagnostic marker for chronic myelogenous leukemia (CML)
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Which of the following diagnostic tools is most effective in detecting small metastases?
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a. tricorder
b. positron emission tomography c. magnetic resonance imaging d. computerized axial tomography e. needle biopsy |
positron emission tomography
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Why is Gleevec is an effective chemotherapeutic for CML?
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it is a competitive inhibitor of BCR-ABL kinase activity
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Why is the human papilloma virus (HPV) is carcinogenic?
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it encodes inhibitors of RB and P53
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What is the term for a malignant tumor of connective tissue?
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sarcoma
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Human papillovirus virus (HPV) has been linked to which of the following malignancies?
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a. lung cancer
b. breast cancer c. cervical cancer d. colon cancer e. skin cancer |
cervical cancer
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Which of the following characteristics of a neoplasm leads to malignancy?
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a. uncontrolled mitosis
b. uncontrolled growth c. loss of contact inhibition d. ability to recruit vascular support e. ability to penetrate the basal lamina |
ability to penetrate the basal lamina
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Which of the following is NOT a component of the basal lamina.
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a. laminin
b. collagen c. proteoglycans d. fibronectin e. all of the above are components of the basal lamina |
fibronectin
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Which of the following best describes the apical-to-basolateral order of occurrence of cell-cell junctions in an epithelial sheet?
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a. adherens junctions – tight junctions – gap junctions – desmosomes
b. adherens junctions – tight junctions – desmosomes – gap junctions c. tight junctions – adherens junctions – desmosomes – gap junctions d. tight junctions – adherens junctions – gap junctions – desmosomes e. tight junctions – desmosomes – adherens junctions – gap junctions |
tight junctions – adherens junctions – desmosomes – gap junctions
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In 2001, which of the following cancers caused the most deaths among American women?
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a. breast cancer
b. stomach cancer c. prostate cancer d. lung & bronchial cancer e. colorectal cancer |
lung & bronchial cancer
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When a gain-of-function mutation increases the probability of developing cancer, the gene that encodes the functional protein is often referred to as …
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an oncogene
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S-Cdk complex prevents multiple DNA replication events by phosphorylating which of the following?
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a. M-Cdk
b. cdc6 [note: phosphorylation of this protein initiates DNA replication] c. origin of replication complex d. p21 e. none of the above |
origin of replication complex
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What is p27?
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a Cdk inhibitor
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Which event triggers chromosomal segregation?
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a. ubiquination of cyclin B by APC
b. degradation of cyclin B c. degradation of cdk1 d. proteolytic cleavage of cohesins by separase e. activation of kinesin motors |
proteolytic cleavage of cohesins by separase
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The minus (-) end directed motor proteins that pull the spindle poles toward the plasma membrane are called …
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dynein
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During anaphase, the forces that drive movement of chromatids toward opposite spindle poles include all of the following except …
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a. plus end depolymerization of kinetochore microtubules
b. poleward flux of tubulin dimers in kinetochore microtubules c. plus end directed kinesin motors acting on interpolar microtubules d. minus end directed dynein motors acting on aster microtubules e. all of the above provide the forces that drive chromosomal segregation |
all of the above provide the forces that drive chromosomal segregation
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During cytokinesis, the orientation of the contractile ring is primarily determined by the location of the …
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centrosomes [note: during M-phase, these are also called "asters"]
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In early anaphase, APC is activated by cdc20. During G1, when cdc20 is depleted, APC activity is maintained by which of the following proteins?
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a. p53
b. Rb c. p21 d. G1-Cdk e. Hct1 |
Hct1
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How do mitogens stimulate mitotic activity?
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increased expression of myc
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Which of the following is NOT required for the full activation of M-Cdk?
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a. binding of cyclin B
b. phosphorylation of cyclin B c. phosphorylation of M-Cdk at the stimulatory site d. dephosphorylation of M-Cdk at the inhibitory site e. all of the above are required for full activation of M-Cdk |
phosphorylation of cyclin B
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As you know, the alkaloid, colchicine, promotes depolymerization of microtubules. Treatment of early frog embryos with colchicine would most likely arrest cells at which phase of the cell cycle?
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G2 phase
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A serious error of DNA replication would most likely arrest cells in which phase of the cell cycle?
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G2 phase
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Most mitogens, growth factors and survival factors signal through ...
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receptor tyrosine kinases
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Which of the following is false regarding gap junctions?
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a. they are formed by proteins called connexins
b. six protein subunits form a single connexon hemichannel c. connexon hemichannels on adjacent cells associate to form the functional gap junction d. calcium and small metabolites can pass through gap junctions e. all of the above are true regarding gap junctions |
all of the above are true regarding gap junctions
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Responsible for preventing the diffusion of solutes between apical and basolateral extracellular compartments in epithelial tissues?
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tight junctions
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