PCQ Stanley Flashcards
In the absence of accessory proteins, cytoskeletal filament lengthening occurs by:
- the addition of subunits at filament ends and shortening occurs by .
In the absence of accessory proteins, cytoskeletal filament shortening occurs by:
- the dissociation of subunits from cytoskeletal filament ends
“Cytoskeletal filaments can grow and shrink, and in the case of actin filaments and microtubules, these dynamics can depend on:”
- actin or tubulin binding proteins
- the breakage and formation of noncovalent interactions between subunits
- the hydrolysis of the nucleotide bound by filament subunits
What is required for microtubule formation in the cell, but not required in cell-free, in vitro microtubule assembly reactions?
the gamma tubulin ring complex
For an actin filament to form in vitro, which of the following is the best answer for what must first be present?
- actin monomers in a GDP bound state
- the gamma tubulin ring complex
- isolated actin monomers
- an aggregate of several subunits
-an aggregate of several subunits
three major cytoskeletal filaments
- actin filament
- microtubule filament
- intermediate filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“subunit that composes this filament binds ATP”
actin filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“subunit that composes this filament binds GTP”
microtubule filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“subunit that composes this filament is a heterodimer”
microtubule filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“unlike the other two, this filament is symmetrical and not polarized”
-intermediate filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“responsible for whole cell movements”
actin filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“forms the contractile ring at the end of cell division”
actin filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“forms the mitotic spindle for chromosome segregation during mitosis”
microtubule filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“helps organelles to be positioned properly within the cell”
microtubule filament
Which of the three major cytoskeletal filaments corresponds to this statement:
“subunit binds ATP to phosphorylate another protein”
None
Where does a microtubule from the mitotic spindle make stable contact with a replicated (mitotic) chromosome?
at the kinetochore
Replicated (mitotic) chromosomes each consist of two sister chromatids which are associated through a protein complex called cohesin. What does a single sister chromatid contain?
one dsDNA molecule
Match the following processes to the phase in the animal cell cycle when they occur.
“Centrosome duplication”
S phase
Match the following processes to the phase in the animal cell cycle when they occur.
“DNA replication”
S phase
Match the following processes to the phase in the animal cell cycle when they occur.
“Chromosome segregation”
M phase
Match the following processes to the phase in the animal cell cycle when they occur.
“Division of the cytoplasm through cytokinesis”
M phase
Match the following processes to the phase in the animal cell cycle when they occur.
“Cell growth”
G1 & G2
Match the following processes to the phase in the animal cell cycle when they occur.
“Determination of whether conditions are favorable for continued growth and division”
G1 & G2
Match the following processes to the phase in the animal cell cycle when they occur.
“Mitosis”
M phase
Select each of the following that is or describes an actin motor protein:
- Dynein
- kinesin
- moves towards plus end of a cytoskeletal filament
- binds and hydrolyzes GTP
- moves towards minus end of a cytoskeletal filament
- binds and hydrolyzes ATP
- myosin
- moves towards plus end of a cytoskeletal filament
- binds and hydrolyzes ATP
- myosin
Select each of the following that is or describes a microtubule motor protein:
- Dynein
- kinesin
- moves towards plus end of a cytoskeletal filament
- binds and hydrolyzes GTP
- moves towards minus end of a cytoskeletal filament
- binds and hydrolyzes ATP
- myosin
- Dynein
- kinesin
- moves towards plus end of a cytoskeletal filament
- moves towards minus end of a cytoskeletal filament
- binds and hydrolyzes ATP
What is required before sister chromatids can separate and the cell transitions from metaphase into anaphase?
- the cleavage of a cohesin subunit
- the attachment of kinetochores to the spindle
- the biorientation of the replicated chromosome
Which of the following underlies regulation of Cdks at different stages of the cell cycle?
- Transcription of cyclin genes
- Degradation of cyclin proteins
- Transcription of Cdk genes
- Degradation of Cdk proteins
- Binding by Cdk inhibitor proteins
- Phosphorylation of Cdk proteins
- Transcription of cyclin genes
- Degradation of cyclin proteins
- Binding by Cdk inhibitor proteins
- Phosphorylation of Cdk proteins
In Dr. Lippincott-Schwartz’s experiment using a photoactivatable version of VSVG (a secreted protein) fused to GFP, she was able to monitor the movement of VSVG:
through the Golgi out to the plasma membrane
For monitoring the movement of a protein through the secretory system, which of the following makes using photoactivatable GFP a preferable approach over regular GFP?
- makes only a fraction of the molecules of a particular protein visible, which can then be followed over time
- using photoactivatable GFP is less hazardous
- can visualize the localization of a protein in living cells
-makes only a fraction of the molecules of a particular protein visible, which can then be followed over time
Select all answers that accurately describe membranes.
- heterogeneous, with distinct clusters of particular phospholipids and membrane proteins
- proteins and lipids can move freely, often exchanging between monolayers
- proteins and lipids can move freely in a lateral direction, within a monolayer
- well mixed, with a random distribution of phospholipid types, cholesterol, and membrane proteins
- heterogeneous, with distinct clusters of particular phospholipids and membrane proteins
- proteins and lipids can move freely in a lateral direction, within a monolayer
Match the vesicle origin/destination with its coat protein type.
ER/Golgi
COP II
Match the vesicle origin/destination with its coat protein type.
Golgi/ER
COP I
Match the vesicle origin/destination with its coat protein type.
Plasma membrane/endosome
Clatherin
What can facilitate vesicle coat protein binding to begin vesicle budding?
- association of GTPases with the donor membrane
- the particular phosphorylation pattern on the head groups of phosphatidylinositol
What is the correct order of events that leads to vesicle fusion in cells?
Tethering, docking, fusion
Which of the following describe Rab effectors?
- interact with Rab
- cytoskeletal motor proteins
- vesicle tethering proteins
- are only transmembrane proteins
- interact with Rab
- cytoskeletal motor proteins
- vesicle tethering proteins
Which of the following cycles between being cytosolic and membrane-associated?
- PI 3-kinase
- v-SNAREs
- Rab proteins
- NSF
- t-SNAREs
- PI 3-kinase
- Rab proteins
- NSF
