D103 Exam Questions with Correct Answers
Which of the following statements is true for phospholipids and sphingolipids?
Both have an amphiphatic organization
Why is cholesterol able to integrate into a lipid bilayer?
Because it prevents the dense packing of phospholipids
Which of the following statement best describes how bacteria in a hot spring control the
fluidity of their plasma membrane?
They increase the percentage of lipids with unsaturated hydrocarbon chains in their plasma
membrane.
Which activity can only be done by a transmembrane protein?
To signal from one side of the membrane to the other
Imagine a small synthetic vesicle made from pure phospholipids enclosing an interior
lumen containing 1 mM glucose and 1 mM sodium chloride.If the vesicle is placed in
pure water, which of the following happens fastest?
H2O diffuses in.
Which of the following transporters moves the two solutes in the direction indicated by
the arrow only by active transport? The concentration of both solutes (shown as small
red circles and blue squares) is higher outside of the cell.
E (needs picture )
In contrast to transporters, channel proteins in cellular membranes ...
can only mediate passive transport.
,A neuron's repetitive firing rate is limited by an absolute refractory period, during
which a new action potential cannot be generated. Which event is chiefly responsible for
this limit?
Inactivation of voltage-gated Na+ channels.
Which of the following processes takes place in the inner membrane of mitochondria?
electron transport between components of the respiratory chain
Which of the following statements is NOT correct regarding mitochondrial DNA
(mtDNA)?
Most proteins that function in mitochondria are encoded by mtDNA.
Which of the following statements best describes a factor(s) that is critical for
establishing the steep electrochemical proton gradient across the inner membrane,
which then drives ATP synthesis?
A pH gradient and a membrane potential across the inner mito membrane
Which of the following factors is critical for the import of proteins into the
mitochondrial matrix?
TOM complex
Indicate the identity of the cytoskeletal elements shown in the drawings of animal cells
below. PICTURE MISSING
(1) microtubules, (2) intermediate filaments, (3) actin
Which of the following statements describes a correct fact about cytoskeletal filaments?
The building blocks of F-actin and microtubules are globular proteins.
, A in vitro polymerization reaction of F-actin or microtubules from their subunits is
characterized by a lag phase. Which of the following processes occurs during this lag
phase?
Filaments are nucleated
How does thymosin affect F-actin dynamics?
It induces F-actin depolymerization because it lowers the concentration of available G-actin
ATP in the cytosol
Which of the following domains is shared by all myosins?
ATP-binding domain
Which of the following answers describes the most direct consequence of tropomyosin
binding to F-actin in muscle cells?
Myosin binding to F-actin is blocked
Which of the following statements best describes the function of cofilin, a protein that
destabilizes the (-) end of F-actin, during cell migration?
It promotes actin network disassembly, freeing up G-actin subunit for assembly of a new
actin network
What is the effect of expressing a dominant active form of the small GTPase Rac1 in a
human neutrophil?
The neutrophil forms lamellipodial extensions.
differences between phospholipids: which of the following statements is the most collect
for all phospholipids ?
Which of the following statements is a correct description of a microtubule?
Which of the following statements is true for phospholipids and sphingolipids?
Both have an amphiphatic organization
Why is cholesterol able to integrate into a lipid bilayer?
Because it prevents the dense packing of phospholipids
Which of the following statement best describes how bacteria in a hot spring control the
fluidity of their plasma membrane?
They increase the percentage of lipids with unsaturated hydrocarbon chains in their plasma
membrane.
Which activity can only be done by a transmembrane protein?
To signal from one side of the membrane to the other
Imagine a small synthetic vesicle made from pure phospholipids enclosing an interior
lumen containing 1 mM glucose and 1 mM sodium chloride.If the vesicle is placed in
pure water, which of the following happens fastest?
H2O diffuses in.
Which of the following transporters moves the two solutes in the direction indicated by
the arrow only by active transport? The concentration of both solutes (shown as small
red circles and blue squares) is higher outside of the cell.
E (needs picture )
In contrast to transporters, channel proteins in cellular membranes ...
can only mediate passive transport.
,A neuron's repetitive firing rate is limited by an absolute refractory period, during
which a new action potential cannot be generated. Which event is chiefly responsible for
this limit?
Inactivation of voltage-gated Na+ channels.
Which of the following processes takes place in the inner membrane of mitochondria?
electron transport between components of the respiratory chain
Which of the following statements is NOT correct regarding mitochondrial DNA
(mtDNA)?
Most proteins that function in mitochondria are encoded by mtDNA.
Which of the following statements best describes a factor(s) that is critical for
establishing the steep electrochemical proton gradient across the inner membrane,
which then drives ATP synthesis?
A pH gradient and a membrane potential across the inner mito membrane
Which of the following factors is critical for the import of proteins into the
mitochondrial matrix?
TOM complex
Indicate the identity of the cytoskeletal elements shown in the drawings of animal cells
below. PICTURE MISSING
(1) microtubules, (2) intermediate filaments, (3) actin
Which of the following statements describes a correct fact about cytoskeletal filaments?
The building blocks of F-actin and microtubules are globular proteins.
, A in vitro polymerization reaction of F-actin or microtubules from their subunits is
characterized by a lag phase. Which of the following processes occurs during this lag
phase?
Filaments are nucleated
How does thymosin affect F-actin dynamics?
It induces F-actin depolymerization because it lowers the concentration of available G-actin
ATP in the cytosol
Which of the following domains is shared by all myosins?
ATP-binding domain
Which of the following answers describes the most direct consequence of tropomyosin
binding to F-actin in muscle cells?
Myosin binding to F-actin is blocked
Which of the following statements best describes the function of cofilin, a protein that
destabilizes the (-) end of F-actin, during cell migration?
It promotes actin network disassembly, freeing up G-actin subunit for assembly of a new
actin network
What is the effect of expressing a dominant active form of the small GTPase Rac1 in a
human neutrophil?
The neutrophil forms lamellipodial extensions.
differences between phospholipids: which of the following statements is the most collect
for all phospholipids ?
Which of the following statements is a correct description of a microtubule?
