29 Questions
During which phase of the cell cycle does DNA synthesis occur?
S phase
What marks the transition from G1 phase to S phase in the cell cycle?
Initiation of DNA replication
What defines the G2 phase of the cell cycle?
Completion of DNA replication
What characterizes cells in the G0 phase of the cell cycle?
Quiescence
If a cell experiences DNA damage in G1 phase, what regulatory mechanism ensures it does not progress into S phase?
DNA replication delay
When do cells prepare for mitosis in the cell cycle?
G2 phase
What is the consequence of p53 mutation and the inability to arrest the cell cycle?
Unregulated cell cycle progression
Which family of cyclin-dependent kinase inhibitors inhibit D-type cyclins from associating with and activating CDK4 and CDK6?
INK4A family
Which member of the CIP/KIP family of cyclin-dependent kinase inhibitors is mentioned in the text?
p21 (p21 CIP1)
What is the primary function of the G2 checkpoint in the cell cycle?
To ensure that DNA replication is complete before mitosis begins
How do cyclin-dependent kinase inhibitors and phosphatases function at the G2 checkpoint?
They inhibit CDK1 to prevent entry into mitosis
What is the role of CDK1 at the G2 checkpoint?
CDK1 is phosphorylated and inhibited to prevent entry into mitosis
What is the primary role of cyclin-dependent kinases (CDKs) and cyclins in the cell cycle?
CDKs and cyclins regulate the progression of the cell cycle by phosphorylating key substrates.
Which statement about cyclins is correct?
Cyclins are expressed in a periodic manner, regulating a series of CDKs.
What is the role of checkpoints in the cell cycle?
Checkpoints monitor specific events related to individual stages and prevent progression if there are problems.
What is the composition of a functional CDK complex?
A CDK complex consists of a catalytic subunit and a regulatory (cyclin) partner.
What external factors influence the activity of CDK-cyclin complexes?
CDK-cyclin complexes are influenced by extracellular cues, such as growth factor signals and the presence of nutrients.
Which statement about the regulation of the cell cycle is incorrect?
CDKs and cyclins are the sole regulators of cell cycle progression.
What is the primary function of the cell cycle checkpoints?
To control the ability of the cell to progress through the cycle
During which phase of the cell cycle does the nucleus increase in size predominantly?
S phase
What happens to the replicated DNA and contents during the mitotic phase?
They are separated and partitioned into the two daughter cells
What is the result of cytokinesis?
The cell splits in two, with each daughter cell having an identical set of chromosomes
Which phase of the cell cycle is characterized by a more or less continuous increase of RNA and protein?
G1 phase
What is the primary function of the cell cycle?
To allow the cell to grow, replicate its contents, and divide
What is the primary function of the D-type cyclins?
To regulate progression through the restriction point in G1 phase
How do CDKs become activated?
CDKs are activated by binding to their partner cyclins and then being phosphorylated by CDK-activating kinase (CAK)
Which phase(s) of the cell cycle are regulated by S phase cyclins?
S phase
How do CDKs become negatively regulated?
CDKs are negatively regulated by CDK inhibitors (CKIs)
Which of the following statements about cyclin concentrations is true?
Cyclin concentrations rise and fall throughout the cell cycle due to synthesis and degradation
Test your knowledge on the regulatory mechanisms that prevent cells with DNA damage in G1 phase from entering S phase, allowing time for DNA repair. Learn about the distinct phases of the cell cycle and the processes that occur during interphase.
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