Exam 3 Flashcards
What is the distinguishing characteristic of a P-type active transport pump?
Question 1 options:
It must be pumped during the cycle.
It must phosphorylate the substance that is being pumped
It must be phosphorylated during the cycle.
It must be deprotonated during the cycle.
It must be protonated during the cycle.
It must be phosphorylated during the cycle.
Diffusion of uncharged molecules depends on the:
Question 2 options:
Both concentration gradient and electrical gradient
Electrical gradient
Concentration gradient
Neither concentration gradient or electrical gradient
Concentration gradient
Cystic fibrosis is a genetic disease caused by a defect in a channel for what ion?
Question 3 options:
Sodium
Chloride
Calcium
Potassium
Chloride
__________ form channels that increase the rate of water movement across the membrane
Question 4 options:
Water conduits
Aquatransporters
Water pumps
Symports
Aquaporins
Aquaporins
What causes the membrane potential to return to a negative value after an action potential has occurred?
Question 5 options:
closing of a voltage-gated K+ channel
opening of a ligand-gated Na+ channel
opening of a voltage-gated K+ channel
opening of a voltage-gated Na+ channel
opening of a voltage-gated K+ facilitated transporter
opening of a voltage-gated K+ channel
As an action potential is initiated, the membrane is ______. This is caused by the ____ of ____ ions.
Question 6 options:
hyperpolarized, efflux, Na+
hyperpolarized, influx, Na+
depolarized, influx, Na+
depolarized, influx, K+
depolarized, efflux, Na+
depolarized, influx, Na+
If placed in a hypotonic solution, a red blood cell will:
Question 7 options:
gain water
lose water
not gain or lose water
gain water
Which part of a neuron conducts impulses toward the cell body?
Question 8 options:
Axon
Dendrites
Terminal knob
Synapse
Dendrites
Which molecules are likely to be brought into a cell using a transport protein?
Question 9 options:
Nonpolar molecules such as O2 and CO2
Polar molecules such as leucine or glucose
Charged atoms such as calcium ions (Ca+) and sodium (Na+) ions
Steroid hormones
Polar molecules such as leucine or glucose
Facilitated diffusion is saturable: eventually adding more solute will have no effect on the rate of transport. Why?
Question 10 options:
Higher solute concentrations aggregate & precipitate
All transporter proteins are working at full capacity
Solute collisions prevent them from binding to transporters
High concentrations become toxic to the cell
All transporter proteins are working at full capacity
Energy input is required for:
Question 11 options:
A. Simple diffusion
B. Facilitated diffusion
C. Osmosis
D. Active transport
B & D
D. Active transport
Steroid hormones can cross the membrane by ….
Question 12 options:
Facilitated diffusion
Osmosis
Simple diffusion
Endocytosis
Active transport
Simple diffusion
Which of the following compounds can diffuse across a phospholipid bilayer?
Question 13 options:
All of these
Cl–
Ca2+
glucose
O2
O2
How do Na+ ions enter a neuron once an action potential is initiated?
Question 14 options:
a ligand-gated Na+ channel
a voltage-gated Na+ channel
an ungated Na+ pump
the Na+/K+-ATPase
a voltage-gated Na+ channel
A protein pump is required for:
Question 15 options:
Facilitated diffusion
Active transport
Simple diffusion
Osmosis
Active transport
Paramecium have contractile vesicles that continuously expel water from the cell. This suggests that they live in a(n) __________ environment.
Question 16 options:
Hypotonic
Hypertonic
Isotonic
Hypotonic
Influx of Na+ into a cell would be:
Question 17 options:
Opposed by concentration gradient, driven by electrical gradient
Opposed by concentration gradient and by electrical gradient
Driven by concentration gradient, opposed by electrical gradient
Driven by concentration gradient and by electrical gradient
Driven by concentration gradient and by electrical gradient
A transport protein is required for:
Question 18 options:
Active transport
B & D
Facilitated diffusion
Osmosis
Simple diffusion
Facilitated diffusion
What accompanies transport by facilitated transporters and pumps?
Question 19 options:
rigidity
softness
α-helix secondary structure
β-pleated sheet secondary structure
conformational change
conformational change
Where is the nucleus located in a neuron?
Question 20 options:
axon hillock
axon
dendrites
cell body
terminal knob
cell body
What does the sequence of glycosyltransferases in the cell’s cytomembrane system control?
Question 1 options:
the sequence of nucleotides on glycoproteins and nucleotide sugars in the cytoplasm
the sequence of sugars on the oligosaccharide chains of a secretory glycoprotein
the sequence of nucleotides on glycoproteins
the sequence of nucleotide sugars in the cytoplasm
the sequence of sugars on the oligosaccharide chains of a secretory glycoprotein
Neurotransmitters are released from synaptic vesicles into the synaptic cleft. Specifically at the neuromuscular junction, _____________ is the neurotransmitter released in response to an influx of _________________ into the presynaptic cell (axon terminal).
Question 2 options:
Sodium; calcium
Calcium; sodium
Acetylcholine; sodium
Acetylcholine; calcium
Acetylcholine; calcium
Which part of a neuron conducts impulses toward the cell body?
Question 3 options:
Dendrites
Terminal knob
Synapse
Axon
Dendrites
Which of the following happens after the SRP has been released from the signal peptide and the ribosome that has just bound to the translocon?
Question 4 options:
Protein synthesis restarts.
Protein synthesis is temporarily suspended, and ribosomes are released from the translocon.
Ribosomes are released from the translocon.
Ribosomes are conveyed to the SER.
Protein synthesis is temporarily suspended.
Protein synthesis restarts.
To what amino acid residue of a polypeptide are N-linked oligosaccharide chains attached as that polypeptide enters the RER lumen through the translocon?
Question 5 options:
asparagine
serine
aspartic acid
threonine
arginine
asparagine
Which structure is not part of the endomembrane system?
Question 6 options:
Golgi apparatus
nuclear envelope
endoplasmic reticulum
chloroplast
chloroplast
A protein is transported in a secretory vesicle and discharges into the extracellular space in a continuous fashion. What type of secretion is this?
Question 7 options:
unregulated
constitutive
regulated
biosynthetic
constitutive
The smooth endoplasmic reticulum is responsible for all of the following except:
Question 8 options:
sequestration of calcium ions
protein synthesis
synthesis of steroid hormones
detoxification in the liver
protein synthesis
Asymmetry of cellular membranes is established initially in the:
Question 9 options:
chloroplast
endoplasmic reticulum
nucleus
mitochondria
endoplasmic reticulum
The signal sequence is found at the N-terminus of secretory proteins and is recognized by:
Question 10 options:
translocon
signal receptor partition
signal recognition particle
other secretory proteins
signal recognition particle
Where does building the oligosaccharide chain for glycosylation take place?
Question 11 options:
On a protein carrier
On a lipid carrier
All of these are correct
Directly on the polypeptide
Any of these are possible
On a lipid carrier
The first sugars added to dolichol phosphate are:
Question 12 options:
mannose
glucose
fructose
N-acetylglucosamine
N-acetylglucosamine
Which of the proteins below are NOT made on the membrane-bound ribosomes of the RER?
Question 13 options:
peripheral proteins attached to the inner surface of the plasma membrane
soluble lysosomal proteins
enzymes in plant vacuoles
proteins of the extracellular matrix
all of these are made on membrane-bound ribosomes
peripheral proteins attached to the inner surface of the plasma membrane
Dolichol phosphate ____________.
Question 14 options:
c) is located in the membrane of the rough ER membrane
a) is a sphingolipid
b) is responsible for donating a block of carbohydrates to domestic proteins as they enter the RER lumen
d) and its attached proteins flip from the leaflet of the RER membrane facing the cytoplasm to the leaflet facing the lumen of the RER
c) is located in the membrane of the rough ER membrane
How do Na+ ions initially enter a post-synaptic neuron after the action potential reaches the synapse of its partner?
Question 15 options:
a ligand-gated Na+ channel
the Na+/K+-ATPase
an ungated Na+ pump
a voltage-gated Na+ channel
a ligand-gated Na+ channel
How do integral membrane proteins enter the lipid bilayer?
Question 16 options:
They insert into the membrane from the cytosol after their synthesis is complete.
The translocon channel has a side gate that continuously opens and closes, giving each nascent polypeptide segment a chance to partition itself into the lipid bilayer’s hydrophobic core.
They are inserted into the membrane by BiP during folding
The membrane is disrupted and proteins are incorporated during reassembly.
They insert into the membrane from the RER lumen after their synthesis is complete.
The translocon channel has a side gate that continuously opens and closes, giving each nascent polypeptide segment a chance to partition itself into the lipid bilayer’s hydrophobic core.
What effect does the binding of the signal recognition particle (SRP) to the ribosome and the growing polypeptide chain have on protein synthesis?
Question 17 options:
Protein synthesis ceases temporarily.
No effect on protein synthesis
Protein synthesis is terminated
Protein synthesis accelerates.
Protein synthesis ceases permanently.
Protein synthesis ceases temporarily.
Which of the following is a function associated with the smooth endoplasmic reticulum in at least some cells?
Question 18 options:
synthesis of steroid hormones
detoxification of many organic compounds, like barbiturates and ethanol
sequestration of calcium Ca2+ ions within the cisternal space
all of these are correct
all of these are correct
The correct order of passage of proteins produced in the biosynthetic pathway is:
Question 19 options:
endoplasmic reticulum, Golgi complex, plasma membrane, lysosome
endoplasmic reticulum, lysosome, Golgi complex, plasma membrane
endoplasmic reticulum, lysosome, secretory vesicle, plasma membrane
endoplasmic reticulum, Golgi complex, secretory vesicle, plasma membrane
endoplasmic reticulum, Golgi complex, plasma membrane, secretory vesicle
endoplasmic reticulum, Golgi complex, secretory vesicle, plasma membrane
How do Na+ ions enter a neuron once an action potential is initiated?
Question 20 options:
a ligand-gated Na+ channel
an ungated Na+ pump
the Na+/K+-ATPase
a voltage-gated Na+ channel
a voltage-gated Na+ channel
Which of the following is not a mechanism by which organelles maintain their protein composition?
Question 1 options:
Scavenging of escaped lipids and return back to their home compartment
Retention of resident proteins excluded from transport vesicles
Retrieval of escaped proteins back to their compartment
Scavenging of escaped lipids and return back to their home compartment
Coated vesicles may be covered by all of the following EXCEPT:
Question 3 options:
COPI
ubiquitin
Clathrin
COPII
ubiquitin
The current model of movement through the Golgi complex suggests that each cisterna matures from cis to trans and transport vesicles carry Golgi enzymes _____________.
Question 2 options:
anterograde
retrograde
from cis to trans
to lysosomes
retrograde
Which of the following is not a filamentous structure of the cytoskeleton?
Question 6 options:
Intermediate filaments
Ligamentous filaments
Actin filaments
Microtubules
Ligamentous filaments
The ____________ functions as a major sorting station, directing proteins to various destinations.
Question 4 options:
rough ER
trans Golgi network
Lysosome
ribosome
trans Golgi network
Which of the following processes does NOT take place in the Golgi complex?
Question 5 options:
processing of membrane proteins
glycosylation of glycoproteins and glycolipids
processing of lysosomal proteins
digestion of misfolded proteins
digestion of misfolded proteins
Targeting vesicles to a particular compartment includes the following steps EXCEPT:
Question 7 options:
coating of vesicles
movement of vesicles
docking of vesicles
tethering of vesicles
coating of vesicles
_____________ residues act as an “address” for delivery of proteins to lysosomes.
Question 8 options:
ubiquitin
Mannose 6-phosphate
selenocysteine
methionine
Mannose 6-phosphate
What family of proteins is important in recruiting tethering proteins to membrane surfaces of vesicles and target compartments?
Question 9 options:
Raf
Ras
Rho
Rab
Rab
Which type of coated vesicle moves materials from the ER to the ERGIC and Golgi?
Question 10 options:
COPI-coated vesicles
COPIII-coated vesicles
Clathrin-coated vesicles
COPII-coated vesicles
COPII-coated vesicles
What protein projects from the A microtubule in a cilium or flagellum, forming an inner and outer arm?
Question 11 options:
dynein
kinesin
myosin
actin
dynein
How is movement of vesicular-tubular carriers directed from the ERGIC to the Golgi complex?
Question 12 options:
fast vesicle propulsion
a slingshot mechanism
random diffusion
movement occurs on microtubule tracks
movement occurs on microtubule tracks
Docking vesicles to target compartments relies on ________ proteins in the vesicle membrane.
Question 13 options:
Rab
v-SNARE
l-snare
MPR
t-SNARE
v-SNARE
Microtubules are polymers of tubulin held together by:
Question 14 options:
Noncovalent bonds
Disulfide bonds
Adapter proteins
Noncovalent bonds
Kinesins generally move toward the __________ of the microtubule to which they are bound.
Question 15 options:
plus end
0 end
minus end
5’-end
plus end
Molecular motors are powered by:
Question 16 options:
hydrolysis of ATP
condensation of ATP
hydrolysis of GDP
proton gradient
hydrolysis of ATP
A microtubule is composed of globular proteins arranged in longitudinal rows called _________.
Question 17 options:
microtubular units
microfilaments
protofilaments
prototubules
protofilaments
Which of the following is not a function of microtubules?
Question 18 options:
They help to maintain cell shape
They support cellular extensions such as axons
They pinch cells apart during cytokinesis
They position various organelles within the cell
They are the moving components of flagella
They pinch cells apart during cytokinesis
The arrangement of microtubules in cilia and flagella is:
Question 19 options:
8 + 3
9 + 3
9 + 2
8 + 2
9 + 2
Cilia and flagella are able to move because their microtubules ______________.
Question 20 options:
shrink and expand longitudinally
go through cycles of assembly and disassembly
slide over one another
expand and contract in diameter
slide over one another
