[Campbell Biology P.300] The eukaryotic cell cycle is tightly regulated by a molecular contr... | Practice Question

The eukaryotic cell cycle is tightly regulated by a molecular control system involving cyclins, cyclin-dependent kinases Cdks , and checkpoints. Which of the following statements correctly describes a characteristic or function of this regulatory system?

• A: Cyclins are enzymes that directly phosphorylate target proteins, driving the cell cycle forward.
• B: The G1 checkpoint is often considered a critical 'restriction point' where a cell commits to dividing or exits the cell cycle to a non-dividing state.
• C: Cancer cells primarily differ from normal cells by forming cell plates instead of undergoing cleavage, which allows them to divide unchecked.
• D: Go-ahead signals for cell cycle checkpoints are solely generated by internal signals, such as DNA damage or incomplete chromosome alignment.
• E: Malignant tumors are characterized by their inability to undergo metastasis due to strict anchorage dependence.