5A Cell Cycle and Mitosis

Scientists determined the total mass of DNA from a sample of animal cells. The masses of equal numbers of cells were taken during three different stages of the cell cycle. Stage I contains cells massed during G1 of the cell cycle.

Which statement best describes the cells during Stage II?

• The cells have replicated their DNA, but have not completed mitosis and cytokinesis.

• The cells have completed mitosis and cytokinesis without replicating their DNA.

• The cells have replicated their DNA and completed mitosis and cytokinesis.

• The cells have temporarily exited the cell cycle without replicating their DNA.

Which model accurately shows a cell progressing through mitosis?

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Which table best compares the events that occur during different stages of the cell cycle?

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The life cycle of a frog is illustrated in the diagram.

Which statement best explains how the cell cycle is important to the life cycle of the frog?

• It enables frogs to produce tadpoles that are clones.

• It allows frogs to grow, develop, and reproduce.

• It prevents overproduction of frog offspring.

• It ensures the best adapted frogs survive and pass on traits to offspring.

The diagram shows the major stages of the cell cycle and the percentage of time spent in each phase.

Which statement best describes why a cell spends the majority of its time in interphase?

• The cell is growing and carrying out processes such as metabolism and DNA replication.

• The cell is aging and processes are stopping as lysosomes clear dead cell matter away.

• The cell needs time to synthesize spindle fibers to complete mitosis.

• The cell needs time to complete cytokinesis.

The karyotype, or chromosomal profile, for humans is shown. A karyotype can be used to investigate genetic disorders.

The chemical colchicine is used in the production of karyotypes. Colchicine prevents spindle fibers from forming during the cell cycle.

What is a result of preventing spindle fibers from forming?

• The cell cycle skips G phase and repeats G phase.

• Mitotic division is skipped, and the cell cycle proceeds to cytokinesis.

• Mitotic division stops in metaphase and cannot proceed to anaphase.

• The cell cycle skips S phase and proceeds to G phase.

Which table shows two steps of DNA replication?

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The activities in the cell cycle occur during specific phases. In which phase of the cell cycle is DNA replicated?

• Mitosis

• G1 phase

• G2 phase

• S phase

This model of the cell cycle includes two arrows that each represent a process in the cycle.

What do the two arrows represent?

• Arrow 1 represents prophase, and Arrow 2 represents interphase.

• Arrow 1 represents mitosis, and Arrow 2 represents meiosis.

• Arrow 1 represents interphase, and Arrow 2 represents mitosis.

• Arrow 1 represents meiosis, and Arrow 2 represents prophase.

Part of the cell cycle is shown in this simplified model.

This part of the cell cycle is best described as the process that —

• duplicates the DNA

• completes cell division

• maintains genetic homeostasis

• synthesizes new molecules