[Campbell Biology P.1098] According to the provided diagrams, which of the following best des... | Practice Question

According to the provided diagrams, which of the following best describes the key difference in the cell cycle between the cleavage stage and the stage after cleavage in a frog embryo?

  • A: After cleavage, the cell cycle includes G1 and G2 phases, allowing for cell growth.
  • B: During cleavage, cells primarily undergo G1 and G2 phases.
  • C: The M phase is absent during cleavage but present after cleavage.
  • D: DNA synthesis (S phase) only occurs after cleavage.

Explanation

The diagrams illustrate that during the cleavage stage, the cell cycle rapidly alternates between S DNA synthesis and M mitosis phases, largely omitting G1 and G2 phases. After the cleavage stage, the cell cycle transitions to a more typical cycle that includes G1 and G2 phases, allowing for cell growth and the production of proteins and cytoplasmic organelles, as stated in the text.