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Marlow Works

AP Biology / Unit 4

Unit 4 · 10–15%

Cell Communication and Cell Cycle

Cells send signals, divide on a schedule, and stop when the schedule says stop.

Start first lessonUnit practice

Topics

  • Reception, transduction, response
  • Feedback
  • Mitosis
  • Checkpoints and cancer as failed control

Lessons

Key terms

Original practice

Marlow Works questions. If this unit does not have its own items yet, you will see other questions from the same course.

1 of 3Membranes · medium · multiple choice

A cell’s surface-area-to-volume ratio is important because it affects:

Original Marlow Works item — not a College Board question.

Take your time—this is practice, not a test.

Review checklist

  1. 01Label reception, transduction, and response on a pathway sketch.
  2. 02Name the job of mitosis versus the job of cytokinesis.
  3. 03Explain one way a failed checkpoint can raise cancer risk.

Related resources

External links with reuse status. Marlow Works is independent and does not copy restricted exam or textbook material.

  • Official / link only

    AP Biology course page

    Official eight-unit framework, science practices, and lab resources.

    College Board · All rights reserved · accessed 2026-10-01

    Open source

  • Reference only — do not copy

    OpenStax Biology 2e

    Biology reference with commercial-use restrictions on the current publisher page.

    OpenStax · CC BY-NC-SA 4.0 with additional restrictions · accessed 2026-10-01

    Link only unless permission is obtained.

    Open source