Scientists used to describe the cell cycle as one cell division after another with a resting phase after each division. This in-between phase was called interphase. With the development of stronger, more powerful microscopes, scientists now know that a lot of processes occur during interphase. A cell spends the majority of its life in interphase. During interphase, the cell prepares for cell division and conducts “normal” cell activities such as growth and obtaining nutrients.

Interphase is divided into three main phases, G₁, S phase, and G₂. A cell can enter a fourth phase, G₀. The time that a cell spends in each phase varies based on the type of cell and the environment the cell is in.

To learn more about each phase of interphase, click on the image map below.

Watch the following animation to learn what happens during DNA replication. Pay close attention to the function of two enzymes, DNA helicase and DNA polymerase.

Let’s see what you learned after watching the video by answering the following questions.

1. The enzyme responsible for adding new nucleotides to the open strand of DNA and checking for duplication is ____________________.

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   Check Your Answer

   DNA Polymerase

2. The enzyme responsible for unzipping the DNA is __________________.

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   Check Your Answer

   DNA Helicase

3. Match the following descriptions with the pictures below.