OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Prepare for the OCR GCSE Biology Exam with detailed quizzes, flashcards, and explanations. Enhance your understanding of biology concepts and get exam-ready today!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.


During which phase does the cell replicate its DNA?

  1. G1 phase

  2. Gap phase two

  3. S phase

  4. Mitosis

The correct answer is: S phase

The S phase, or synthesis phase, is a critical part of the cell cycle where DNA replication occurs. During this phase, each chromosome is duplicated, resulting in two sister chromatids for each chromosome. This is essential for cell division, ensuring that when the cell divides, each daughter cell receives an identical set of chromosomes. The S phase follows the G1 phase, where the cell grows and carries out its normal functions. After the S phase, the cell enters the G2 phase, preparing for mitosis, which is the actual process of cell division. Thus, the S phase is specifically designated for DNA replication, making it the correct answer.