CELL CYCLE CONTROL SYSTEM

What is checked at the G1 checkpoint in the cell cycle?

• Cell shape, oxygen levels, cell division, and protein synthesis
• Chromosome number, cell volume, enzyme activity, and cell membrane

• Cell polarity, pH levels, organelle function, and cell signaling
• Cell size, nutrients, growth factors, and DNA damage

Which checkpoint ensures that DNA replication is complete and the replicated DNA is not damaged?

• G1 checkpoint
• G2 checkpoint
• S checkpoint
• M checkpoint

What happens if a cell receives a go-ahead signal at the G1 checkpoint?

• It will enter a state of dormancy.
• It will skip the S phase and proceed directly to mitosis.
• It will proceed to the S phase of the cell cycle.
• It will self-destruct.

Which checkpoint ensures that all chromosomes are attached to spindle fibers before proceeding to anaphase?

• G1 checkpoint

• G2 checkpoint

• S checkpoint

• M checkpoint

Which molecule acts as a go-ahead signal at cell cycle checkpoints?

• Cellular division kinase (Cdk)
• Cyclin-dependent kinase (Cdk)
• Cyclin-dependent receptor (Cdr)
• Cycle-regulating protein (Crp)

What will happen if any chromosomes are not attached to spindle fibers during mitosis?

• Spindle fibers will detach from centromeres
• Cells will undergo apoptosis
• The cell will receive a stop signal

• Chromosomes will replicate

What gene is activated in response to DNA damage or cell cycle abnormalities?

• p21

• BRCA1
• RB1
• p53

What is the primary role of the p53 gene when activated?

• Encode a protein activator that activates other genes

• Induction of apoptosis
• Inhibition of DNA repair
• Promotion of cell growth

Which gene is activated by the protein produced by the p53 gene?

• p73
• p53R2
• p63
• p21

What does the p21 gene encode for?

• Cyclin-dependent kinase inhibitor

• DNA repair enzyme

• Spindle fiber

• Cyclin-dependent kinase inhibitor 2A (CDKN2A)