Cell Biology Final exam

Question: Adjacent hepatocytes are held together by:
cell junctions.
endothelial cells.
microvilli.
extracellular matrix.

cell junctions.

Question: Spaces between adjacent endothelial cells allow red blood cells to leave the capillaries.
True
False

False

Question: Detecting extracellular signals is important for survival but not for mating and reproduction.
True
False

False

Question: Cells can be either signaling cells or targeting cells but not both.
True
False

False

Question: Which of the following lists the events in the proper order?
cellular response, cell communication, signal transduction
signal transduction, cell communication, cellular response
signal transduction, cellular response, cell communication
cell communication, signal transduction, cellular response

cell communication, signal transduction, cellular response

Question: A specific cellular response will depend on:
the extracellular signal, the receptor, and cell type.
only the extracellular signal.
only the extracellular signal and the receptor.
only the extracellular signal and cell type.

the extracellular signal, the receptor, and cell type.

Question: Cells in a multicellular organism work not for their own survival but rather for the survival of the entire multicellular organism.
True
False

True

Question: A cell that specializes in information processing at the organismal level does not undergo signal detection at the cellular level.
True
False

False

Question: Which of the following modes of cell communication is the most "public"?
cell-to-cell communication
paracrine signaling
endocrine signaling
neuronal signaling

endocrine signaling

Question: In which of the following modes of cell communication does the signal travel over a long distance but only to a specific target cell?
neuronal signaling
paracrine signaling
cell-to-cell communication
endocrine signaling

neuronal signaling

Question: Which of the following is the most common type of extracellular signal?
mechanical stimulation
light
chemical
membrane potential

chemical

Question: The vast majority of chemical signals bind to transmembrane receptors in the cell membrane.
True
False

True

Question: All cells in a multicellular organism respond to all extracellular signals.
True
False

False

Question: The ability of a cell to either detect or ignore a signal is based on the presence or absence of a receptor for that signal.
True
False

True

Question: A looped pathway where a downstream event inhibits an earlier upstream event is called:
convergent pathway.
negative feedback
divergent pathway.
positive feedback.

negative feedback

Question: The binding of just a few chemical signals to a few receptors usually results in just a few activated intracellular proteins.
True
False

False

Question: Which of the following amino acids are dual-specificity kinases NOT able to phosphorylate?
threonine
methionine
serine
tyrosine

methionine

Question: Phosphorylation of a given residue within a protein usually results in:
deactivation.
activation.
either activation or deactivation, depending on the protein being phosphorylated.
either activation or deactivation, depending on the kinase.

either activation or deactivation, depending on the protein being phosphorylated.

Question: G-proteins are used as (choose the best answer):
tyrosine kinases.
serine/threonine kinases.
molecular on/off switches.
molecular timers.

molecular timers.

Question: Some heterotrimeric G-proteins are tethered to the intracellular side of the cell membrane while others are not.
True
False

False

Question: Which protein stimulates the release of spent GDP to restart the G-protein cycle?
guanine nucleotide exchange factor (GEF)
guanine nucleotide dissociation inhibitor (GDI)
GDP-bound G-proteins
GTPase-activating protein (GAP)

guanine nucleotide exchange factor (GEF)

Question: Which protein binds GTP-bound G-proteins to stimulate GTP hydrolysis?
guanine nucleotide exchange factor (GEF)
guanine nucleotide dissociation inhibitor (GDI)
GDP-bound G-proteins
GTPase-activating protein (GAP)

GTPase-activating protein (GAP)

Question: Which of the following is a primary messenger?
an enzyme in a signal transduction pathway
a transmembrane receptor
a G-protein
an extracellular chemical signal

an extracellular chemical signal

Question: Second messengers can be rapidly produced by enzymes.
True
False

True

Question: Which is NOT one of the three main types of membrane receptors?
gated ion channels
RTKs
GPCRs
soluble receptors

soluble receptors

Question: The gas nitric oxide (NO) can bind to a receptor tyrosine kinase (RTK) in the cell membrane.
True
False

False

Question: The influx of ions through gated ion channels usually leads to a change in membrane potential.
True
False

True

Question: Gated ion channels are typically found in neurons and muscle cells.
True
False

True

Question: GPCRs are structurally ___ and functionally ___.
diverse, similar
diverse, diverse
similar, diverse
similar, similar

similar, diverse

Question: GPCRs represent the largest family of cell membrane receptors in all eukaryotes.
True
False

True

Question: Unlike GPCRs, enzyme-coupled receptors do not activate heterotrimeric G-proteins when activated.
True
False

True

Question: Each RTK monomer possesses an intracellular ___ domain.
serine/threonine phosphatase
tyrosine phosphatase
tyrosine kinase
serine/threonine kinase

tyrosine kinase

Question: The binding of an extracellular chemical signal to a GPCR leads to ___ of a ___.
activation, monomeric G-protein
inhibition, monomeric G-protein
activation, heterotrimeric G-protein
inhibition, heterotrimeric G-protein

activation, heterotrimeric G-protein

Question: GPCRs are single-pass transmembrane proteins woven into the membrane during translation.
True
False

False

Question: When a heterotrimeric G-protein binds GTP, what happens to its subunits?
the β-subunit dissociates from the α/γ-complex
the α-subunit dissociates from the β/γ-complex
the γ-subunit dissociates from the α/β-complex
the three subunits associate with each other

the α-subunit dissociates from the β/γ-complex

Question: When acetylcholine binds to a GPCR on a heart cell membrane, ___ channels ___.
K+, close
K+, open
Na+, close
Na+, open

K+, open

Question: The ion channels in a heart cell membrane are activated by the α-subunit of a heterotrimeric G-protein.
True
False

False

Question: The two most common enzyme targets of heterotrimeric G-proteins are adenylyl cyclase (AC) and phospholipase C (PLC).
True
False

True

Question: AC and PLC are activated by the same type of heterotrimeric G-proteins.
True
False

False

Question: When active, adenylyl cyclase produces:
AMP
cADP
cAMP
ADP

cAMP

Question: In a GPCR-mediated pathway, when does the signal first diffuse throughout the cytosol?
after the α-subunit separates from the β/γ-complex
after the activation of the heterotrimeric G-protein
after binding of the signal to the GPCR
after the activation of AC

after the activation of AC

Question: PLC cleaves ___ into ___ and ___.
IP₃, PIP₂, DAG
DAG, PIP₂, IP₃
IP, PIP₃, DAG
PIP₂, IP₃, DAG

PIP₂, IP₃, DAG

Question: Which is secreted by the pancreas in response to low blood glucose?
glycolysis
glucagon
glycogen
glucose

glucagon

Question: Which is activated in response to low blood glucose?
phospholipase A (PLA)
phospholipase C (PLC)
protein kinase C (PKC)
protein kinase A (PKA)

protein kinase A (PKA)

Question: The binding of an extracellular signal to RTK monomers results in ___ of the extracellular domains.
inhibition
dimerization
cleavage
activation

dimerization

Question: Regardless of RTK type, each monomer binds one extracellular chemical signal.
True
False

False

Question: The activation loop blocks the:
dimerization domain
transmembrane domain
ATP-binding site
extracellular signal from binding the receptor

ATP-binding site

Question: During trans-autophosphorylation, each monomer phosphorylates itself.
True
False

False

Question: Once an RTK dimer is active, the signal transduction pathway diverges into two.
True
False

True

Question: SH2 and PTB domains bind phosphorylated ___ residues in the ___ of activated RTKs.
tyrosine, C-terminal tail
threonine, C-terminal tail
tyrosine, kinase domain
threonine, kinase domain

tyrosine, C-terminal tail

Question: In EGF-mediated signaling, phosphorylated RTK C-terminal tails recruit:
Grb2
MAPK
Ras
Sos

Grb2

Question: MAPKK phosphorylates:
MAP
MAPKK
MAPK
MAPKKK

MAPK

Question: Ca²⁺ is used in GPCR-mediated but not RTK-mediated signal transduction.
True
False

False

Question: The major Ca²⁺ binding protein in eukaryotic cells is:
CaM
Ca²⁺
tyrosine kinase
CBP

CaM

Question: CaMKII is involved in metabolism and digestion.
True
False

False

Question: GPCR and RTK pathways commonly interact.
True
False

True

Question: Intermediate filament monomers lack polarity.
True
False

True

Question: Structure of intermediate filaments is best described as:
rope-like
tubular
globular
polar

rope-like

Question: Intermediate filaments absorb mechanical load by stretching.
True
False

True

Question: Intermediate filaments are found in the:
nucleus and cytosol
extracellular matrix only
cytosol and extracellular matrix
nucleus only

nucleus and cytosol

Question: Hair is made from:
vimentins
lamins
neurofilaments
keratins

keratins

Question: Intermediate filaments differ in their central α-helical domain.
True
False

False

Question: Which is NOT a cytoskeleton function?
molecular roadways
aerobic cellular respiration
position organelles
cell shape changes

aerobic cellular respiration

Question: Which is NOT a main cytoskeleton component?
microtubules
macrofilaments
intermediate filaments
actin filaments

macrofilaments

Question: Cytoskeleton order (thickest to thinnest):
microtubules, intermediate filaments, actin filaments
actin filaments, microtubules, intermediate filaments
microtubules, actin filaments, intermediate filaments
actin filaments, intermediate filaments, microtubules

microtubules, intermediate filaments, actin filaments

Question: Prokaryotic cytoskeleton is made from actin/tubulin homologs.
True
False

True

Question: G-actin has polarity.
True
False

True

Question: Factor NOT influencing actin polymerization:
ATP hydrolysis
G-actin concentration
actin-binding proteins
globular F-actin

globular F-actin

Question: ATP-bound G-actin promotes depolymerization.
True
False

False

Question: The treadmill effect matches polymerization/depolymerization rates.
True
False

True

Question: Actin-binding proteins can promote polymerization or depolymerization.
True
False

True

Question: Myosin moves towards the minus end of F-actin.
True
False

False

Question: Myosin II is powered by ATP hydrolysis.
True
False

True

Question: Muscle contraction is triggered by release of:
Mg²⁺
ATP
GTP
Ca²⁺

Ca²⁺

Question: Fibroblasts attach to the substratum via:
lamellipodia
focal adhesions
CapZ
filopodia

focal adhesions

Question: Fibroblast migration "antennae" are:
filopodia
lamellipodia
focal adhesions
CapZ

filopodia

Question: Polymerizing microtubules have an ATP tip.
True
False

False

Question: Kinesins use ATP to walk towards the ___ end.
plus
minus

plus

Question: ER distribution matches:
microtubules
actin filaments
intermediate filaments
plectin

microtubules

Question: Dyneins are ___ than kinesins and walk towards the ___ end.
larger, minus
smaller, plus
larger, plus
smaller, minus

larger, minus

Question: Dyneins position the ___ within the cell.
Golgi
nucleus
lysosomes
ER

Golgi

Question: Non-motile cilia function as sensory structures.
True
False

True

Question: Which is a type of MTOC?
basal body
dynein
axoneme
non-motile cilium

basal body

Question: PHOTO HERE (Hippo signaling pathway diagram)

PHOTO HERE (Diagram showing Mst1/2, Sav1, Lats1/2, YAP/TAZ interactions)

Question: PHOTO HERE (Apoptosis intrinsic pathway regulation)

PHOTO HERE (Diagram of Bcl-2 family proteins regulating apoptosis)

Question: PHOTO HERE (CRISPR-Cas system)

PHOTO HERE (CRISPR-associated proteins and bacterial defense mechanism)

Question: PHOTO HERE (mTORC1 signaling pathway)

PHOTO HERE (Diagram of mTORC1 regulation by PTEN and Akt)