Which of the following is NOT a mechanism used to regulate cyclin-Cdk complexes?
Acetylation
Inhibitory protein binding
Polyubiquitinylation
Phosphorylation correct answers Acetylation
Both the Anaphase Promoting Complex (APC/C) and the SCF complex help to advance cells through the cell cycl...
MMG 409 Unit 3(Errorless Answers)
Which of the following is NOT a mechanism used to regulate cyclin-Cdk complexes?
Acetylation
Inhibitory protein binding
Polyubiquitinylation
Phosphorylation correct answers Acetylation
Both the Anaphase Promoting Complex (APC/C) and the SCF complex help to advance
cells through the cell cycle by targeting proteins for degradation by the proteosome. How do their mechanisms of action differ? correct answers The APC/C is activated by binding with a protein partner that directs it to target proteins for degradation, while the SCF identifies target proteins when they are phosphorylated in order to direct proteins to the proteosome
A critical cell cycle checkpoint occurs between which two mitotic stages? correct answers Metaphase and Anaphase
Which of the following is a true statement about cell cycle checkpoints?
Passage through checkpoints is irreversible
The decision to move through checkpoints is based solely on extracellular conditions
Cells can shift from G2 back to G1 if extracellular conditions are not supportive of mitosis
Both a and b are true
All of the above statements are true correct answers Passage through checkpoints is irreversible
Cdks possess the kinase activity required for cell cycle progression. What protein is required to both drive Cdk activation and specificity? correct answers Cyclins
M-Cdk activation throughout the cell can occur rapidly due to positive feedback loops. Which of the following statements is an accurate description of how these positive feedback loops function? correct answers Active M-Cdk can negatively regulate the activity of the inhibitory kinase Wee1 and activates Cdc25 phosphatase
What is an important difference between the G1 and G2 phases of the cell cycle? correct answers Cells duplicate their genomic material after the G1 phase, and therefore have twice as much genetic material in the G2 phase
One of the most common signals that can inhibit the action of cyclin-CDK complexes during the cell cycle is: correct answers DNA damage
How does the regulation of cyclin-Cdk complexes by inhibitory phosphorylations resemble the inhibition by the binding of CKIs? correct answers Both forms of regulation
directly interfere with the active sites of the Cdks and prevent the binding of substrates Flow cytometry is a powerful tool for analyzing cell cycle progress in a population of cells. In what stage of the cell cycle are the cells in Peak 1 likely to be? correct answers G1
Microtubule attachment to the kinetochore is critical for mitotic progression. How do microtubules interact with the kinetochore to facilitate sister chromatid segregation? correct answers Microtubules are embedded in the kinetochore where they are bound by Ndc80 to link sister chromatids to the microtubules
In order for cells to advance from metaphase to anaphase, the cohesin rings holding sister chromatids together must be degraded. What protein is responsible for this action,
and how is it regulated? correct answers Separase cleaves the cohesin rings but is held
in an inactive state by Securin until the APC/C activates
Polar ejection force results in the arms of chromosome lagging behind the centromeres during anaphase. Loss of which of the following motor protein(s) would result in the loss
of this "polar wind"? correct answers Kinesin-4 and Kinesin-10
What is the functional difference between interpolar microtubules and kinetochore microtubules? correct answers Interpolar microtubules form anti-parallel associations with the opposing centrosome while kinetochore microtubules connect sister chromatids
to spindle poles
Which of the following statements is NOT a true statement comparing cohesin and condensin?
Both proteins are important for organizing re-structing genomic material for mitosis
Both proteins share a similar structure, with two arms interacting through hinge domains
with ATPase head groups
Condensin functions primarily to hold sister chromatids together, while cohesin largely compacts the duplicated genomes
All of the above statements are true correct answers Condensin functions primarily to hold sister chromatids together, while cohesin largely compacts the duplicated genomes
The Origin Recognition Complex (ORC) is one of the first protein factors that identifies and binds to an origin of replication. After the ORC is bound, the next critical functional component of the prereplicative complex recruited is: correct answers Mcm Helicase
What are the critical signals that indicate proper biorientation of sister chromatids and thereby promote metaphase-to-anaphase progression? correct answers Attachment of the kinetochores and tension between sister chromatids
Microtubule flux generates an important poleward force on sister chromatids during the M phase. What is happening at each end of the microtubule to maintain this flux? correct answers Tubulin is removed at the - end of spindle microtubules while also being added at the + end, resulting in treadmilling Motor proteins perform which of the following functions during mitosis?
Positioning the centrosomes at the poles
Maintaining centrosome positioning in the cell relative to each other
Moving sister chromatids to the metaphase plate
All of the above
None of the above correct answers All of the above
Origins are regulated to only fire once during every round of the cell cycle. Which of the following is NOT a mechanism that prevents the re-use of origins?
ORC inactivation
Inhibition of Mcm Helicase loading
Cohesin loading
Both a and b
All of the above correct answers Cohesin loading
Fas signaling is an example of the activation of an extrinsic apoptotic signaling pathway.
How does Fas binding to the Fas Death receptor impact apoptosis in the target cell? correct answers Fas binding recruits adaptors and initiator caspases into the Death Inducing Signal Complex (DISC) to drive caspase activation
What are two major ways in which survival signaling can inhibit apoptosis? correct answers Transcriptional upregulation of anti-apoptotic proteins and activation of anti-
apoptotic proteins
Survival signaling is required for cell survival because without the signals, cells actively: correct answers Promote pro-apoptotic pathways
Cytochrome c is normally sequestered in the intermembrane space of mitochondria where is participates in the electron transport chain. However, it is also an important component of the intrinsic apoptotic pathway. What does cyctochrome c do in this pathway? correct answers Cytochrome c activates Apaf1 to form a heptamer that promotes initiator caspase activation
An important difference between apoptosis and necrosis is: correct answers Apoptotic cells maintain membrane integrity and break down intracellular macromolecules while necrotic cells break open in an unregulated manner
Bcl2 family member proteins can function as either pro or anti apoptotic factors. They are characterized by the inclusion of one or more Bcl Homology (BH) domains. What is true about the BH homology domains? correct answers Initiator caspases are activated by adaptor protein binding, which allows them to function as adaptor proteins for executioner caspases
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