LifeSciTRC.org - Cells alive! - Cell Cycle Worksheet - Free Printable

You’ve uploaded an image titled “CELLS alive! - Cell Cycle Worksheet” with a circular diagram showing the stages of the cell cycle, and numbered lines (1–10) pointing to different parts of the diagram. The goal is to fill in what’s happening at each numbered point.

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🧬 Understanding the Diagram:

The cell cycle consists of:
- Interphase (longest phase — cell grows, duplicates DNA)
- G₁ (Gap 1)
- S (Synthesis — DNA replication)
- G₂ (Gap 2)
- Mitosis (M) — division of the nucleus
- Prophase → Metaphase → Anaphase → Telophase
- Cytokinesis — division of the cytoplasm (often shown as part of M or right after)
- Then back to Interphase for the next cycle.

The diagram shows:
- A large outer circle labeled “interphase” divided into colored segments: blue (G₁), green (S), yellow (G₂), then red/orange for mitosis.
- Arrows show progression clockwise.
- Numbered lines point to specific phases or transitions.

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## ✔ Here's the correct labeling for each number:

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1) → Pointing to the start of interphase / G₁ phase

> Cell grows and carries out normal functions.

*(This is the first gap phase — cell prepares for DNA synthesis.)*

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2) → Pointing to G₁ → S transition

> Cell prepares for DNA replication.

*(Checks for signals and resources before entering S phase.)*

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3) → Pointing to S phase (green segment)

> DNA replication occurs. Chromosomes are duplicated.

*(Each chromosome becomes two sister chromatids.)*

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4) → Pointing to S → G₂ transition

> Cell checks DNA for errors and prepares for mitosis.

*(Ensures DNA was copied correctly before proceeding.)*

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5) → Pointing to G₂ phase (yellow segment)

> Cell grows more, synthesizes proteins needed for mitosis.

*(Final preparation before division.)*

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6) → Pointing to G₂ → M transition

> Cell commits to division; enters mitosis.

*(Checkpoint ensures everything is ready for mitosis.)*

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7) → Pointing to Prophase (beginning of mitosis)

> Chromatin condenses into chromosomes; nuclear envelope breaks down.

*(Spindle fibers begin to form.)*

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8) → Pointing to Metaphase

> Chromosomes line up at the equator (metaphase plate).

*(Spindle fibers attach to centromeres.)*

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9) → Pointing to Anaphase

> Sister chromatids separate and move to opposite poles.

*(Pulled by spindle fibers.)*

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10) → Pointing to Telophase & Cytokinesis

> Nuclear envelopes reform; cytoplasm divides; two daughter cells form.

*(End of mitosis — cells return to interphase.)*

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## 📌 Bonus: What’s happening now? (Center text)

> The cell is cycling through growth, DNA replication, and division to produce two genetically identical daughter cells.

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## ✍️ Final Answer (for worksheet):

| # | What’s happening now? |
|---|------------------------|
| 1 | Cell grows and performs normal functions (G₁ phase). |
| 2 | Cell prepares for DNA replication. |
| 3 | DNA is replicated (S phase). |
| 4 | Cell checks DNA for errors before mitosis. |
| 5 | Cell grows and prepares proteins for mitosis (G₂ phase). |
| 6 | Cell enters mitosis (M phase). |
| 7 | Chromosomes condense; nuclear envelope breaks down (Prophase). |
| 8 | Chromosomes align at the center (Metaphase). |
| 9 | Sister chromatids separate and move apart (Anaphase). |
| 10 | Nuclear envelopes reform; cell splits into two (Telophase & Cytokinesis). |

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✔ This completes the worksheet accurately based on standard biology curriculum and the CELLScalive diagram.

Let me know if you’d like a printable version or flashcards for studying!