Cell Cycle Diagram
Generate cell cycle diagrams, labeled or blank: G1, S, G2 and M with G0, the three checkpoints and their cyclin-CDK pairs, mitosis and cytokinesis, and a cancer version. Made for school biology and cancer research.
Cell cycle diagram examples
Real renders of the prompts shown: a labeled cell cycle with phases timed to 24 hours, a simple worksheet, the checkpoints with their cyclin–CDK complexes and a blank version. Click one to load and edit its prompt.
Reading the labeled cell cycle diagram: 24 hours in one circle
Start at the thin M slice at the top and follow the arrows clockwise. Each arc is drawn to the hours in brackets.
- 1
M phase (0.5 h)
Mitosis, prophase to telophase, then cytokinesis; two daughter cells enter G1.
- 2
G1 (9 h), with G0 to the side
The cell grows under cyclin D–CDK4/6; a cell that stops dividing exits into the G0 loop.
- 3
G1/S checkpoint → S (10 h)
Past the restriction point, cyclin E–CDK2 starts DNA replication and cyclin A–CDK2 carries it on.
- 4
G2 (4.5 h) → G2/M checkpoint
With the DNA fully copied and undamaged, cyclin B–CDK1 sends the cell back into M.
Interphase, cytokinesis, checkpoints: which cell cycle diagram you need
The circle above is the full version. Most lessons and papers use one part of it, or the same cycle drawn another way.
Interphase diagram
G1, S and G2 drawn as three cells rather than three arcs. The nucleus stays intact and the chromatin is loose, so no separate chromosomes are visible; what changes is the content. In G1 the cell grows, in S every chromosome is copied into two sister chromatids and the centrosome is duplicated, in G2 the cell has two centrosomes and builds the proteins for mitosis. Interphase is about 23.5 of the 24 hours, so a cell under the microscope is usually in it.
Cell cycle phases diagram
The ring with a small drawing of the cell at each phase: a small cell in G1, chromosomes doubling in S, a larger cell with two centrosomes in G2, condensed chromosomes in M, two daughter cells after cytokinesis. Ask for “a cell drawn at each phase” or the tool draws the plain labeled ring.
Cell cycle pie chart
Slices sized to the share of time in each phase. For a 24-hour human cell that is G1 135°, S 150°, G2 67.5°, M 7.5°. In the onion root tip lab the slices come from counts instead: the fraction of cells seen in each phase, multiplied by the cycle length, estimates how long that phase lasts. Give the tool your counts or hours and it sizes the slices to them.
Cell cycle and mitosis diagram
The circle with the thin M slice pulled out into a row of cells: prophase, prometaphase, metaphase, anaphase, telophase, then cytokinesis. This is how a mitosis diagram fits into the cycle; mitosis divides the nucleus and is only half an hour of the 24.
Cell cycle diagram with checkpoints
The three checkpoints drawn as gates, each with what it checks: G1/S (cell size, nutrients, growth signals, DNA damage; p53, p21 and Rb act here), G2/M (DNA fully replicated and undamaged), and the spindle checkpoint in metaphase (every kinetochore attached to fibers from opposite poles). Add the cyclin–CDK pairs if the lesson covers regulation.
Cytokinesis diagram
The split of the cytoplasm at the end of M, drawn for both cell types. In an animal cell a contractile ring of actin filaments tightens at the old metaphase plate and pinches the cell in two along a cleavage furrow. In a plant cell Golgi vesicles gather at the metaphase plate, fuse into a cell plate that grows outward from the center, and become the new cell wall between the daughters.
Cancer cell cycle diagram
The normal cycle with its brakes removed: mutated p53 that no longer stops a cell with damaged DNA, lost Rb that no longer holds the G1/S gate, and an oncogene sending a growth signal that never switches off. Ask for the failed checkpoints crossed out, so the contrast with the normal circle is visible at a glance.
Simple cell cycle diagram or drawing
Two parts, interphase and the mitotic phase, or the four phases G1, S, G2 and M with no checkpoints or cyclins. A clean line drawing that students can copy by hand. Say “no regulators” and the circle stays at four or five labels.
Phases of the cell cycle
The phases and checkpoints a labeled cell cycle diagram is normally expected to show, what happens in each and what drives or checks it. This is the default content unless you ask for something else.
| Phase | Part of | What happens | Driven or checked by |
|---|---|---|---|
| G0 | Outside the cycle | Quiescent: the cell carries out its job without preparing to divide | Growth signals return it to G1 |
| G1 (first gap) | Interphase | The cell grows and gathers building blocks and energy for DNA replication | Cyclin D–CDK4/6 |
| G1/S checkpoint | End of G1 | Checks size, reserves, growth signals and DNA damage; the restriction point | p53, p21, Rb; cyclin E–CDK2 lets the cell pass |
| S (synthesis) | Interphase | DNA is replicated into sister chromatids; the centrosome is duplicated | Cyclin A–CDK2 |
| G2 (second gap) | Interphase | The cell makes the proteins needed for mitosis | Cyclin B–CDK1 builds up |
| G2/M checkpoint | End of G2 | Checks that all DNA is replicated and undamaged | Cyclin B–CDK1 triggers entry into mitosis |
| Prophase | M phase (mitosis) | Chromosomes condense; the spindle starts to form | Cyclin B–CDK1 |
| Prometaphase | M phase (mitosis) | The nuclear envelope breaks down; kinetochores attach to spindle fibers | Cyclin B–CDK1 |
| Metaphase | M phase (mitosis) | Chromosomes line up at the metaphase plate | Spindle checkpoint |
| Anaphase | M phase (mitosis) | Sister chromatids separate and move to opposite poles | APC/C, once the spindle checkpoint is satisfied |
| Telophase | M phase (mitosis) | Nuclear envelopes re-form; chromosomes decondense | — |
| Cytokinesis | M phase | The cytoplasm divides: a cleavage furrow in animal cells, a cell plate in plant cells | — |
Arcs follow the timing: in a 24-hour human cell, G1 ≈ 9 h, S ≈ 10 h, G2 ≈ 4.5 h, M ≈ 0.5 h. Timings vary between cell types, so ask for the numbers your course uses and they are drawn instead.
What is the cell cycle?
The cell cycle is the ordered series of events in which a eukaryotic cell grows, copies its DNA and divides into two identical daughter cells: interphase — G1, S and G2 — followed by the mitotic (M) phase of mitosis and cytokinesis, with checkpoints at G1/S, G2/M and metaphase that halt the cycle until conditions are right. Cyclin–CDK complexes drive the cell from one phase to the next.
Key facts
- Interphase takes almost all of the time. In rapidly dividing human cells with a 24-hour cycle, G1 lasts about 9 hours, S about 10 hours, G2 about 4.5 hours and M only about half an hour — which is why a correct diagram draws M as a thin slice.
- DNA is copied once, in S phase. Each chromosome is replicated into two sister chromatids joined at the centromere, and the centrosome is duplicated too; G1 and G2 are growth and preparation gaps on either side.
- Three checkpoints guard the cycle. The G1 checkpoint (restriction point) checks size, reserves, growth signals and DNA damage; the G2/M checkpoint checks that the DNA is fully replicated and undamaged; the spindle checkpoint holds anaphase until every kinetochore is attached to spindle fibers from opposite poles.
- Cyclins rise and fall; CDKs stay. CDK levels stay fairly constant while cyclins come and go: cyclin D–CDK4/6 in early G1, cyclin E–CDK2 at the G1/S transition, cyclin A–CDK2 during S phase and cyclin B–CDK1 at the G2/M transition.
- Cells can leave the cycle into G0. Quiescent cells wait in G0 until a signal returns them to G1; cells that never or rarely divide, such as mature cardiac muscle and nerve cells, stay in G0 permanently.
Blank cell cycle diagram to label
To label the cell cycle on this blank, start at the thin slice at the top and follow the arrows clockwise. Four places where cell cycle labeling most often goes wrong:
- 1
The thin slice is M, and G1 comes next
Mitosis takes half an hour of 24; clockwise from it come G1, then S along the bottom, then G2.
- 2
The loop off G1 is G0
It is an exit for cells that stop dividing, not a fifth phase inside the circle.
- 3
The spindle checkpoint sits inside M
Its red mark is in metaphase, within the M slice; the other two sit at G1/S and G2/M.
- 4
Cyclin E vs cyclin A
The box at the G1/S mark is cyclin E–CDK2; the box under the S arc is cyclin A–CDK2.
Cell cycle vs mitosis: what is the difference?
The cell cycle is the whole life of a dividing cell — growth, DNA replication and division — while mitosis is only the division of the nucleus inside its M phase. Mitosis takes about half an hour of a 24-hour human cell cycle; interphase takes the rest.
| Cell cycle | Mitosis | |
|---|---|---|
| What it covers | Interphase (G1, S, G2) and M phase | Nuclear division within M phase |
| DNA replication | Yes, in S phase | No; the DNA is already copied |
| Stages | G1, S, G2, M (and G0 outside) | Prophase, prometaphase, metaphase, anaphase, telophase |
| Share of a 24-hour human cycle | All 24 hours | About 30 minutes |
| Chromosomes | Mostly semi-condensed chromatin | Condensed and visible under a light microscope |
| Checkpoints | G1/S, G2/M and spindle | The spindle checkpoint, in metaphase |
| Usual diagram | A circle | A row of cells, one per stage |
Draw the cell cycle as a circle and mitosis as a sequence. Cytokinesis is usually counted in the M phase but is a separate process from mitosis.
Common questions about the cell cycle
How do I draw a cell cycle diagram?
Draw a circle, divide it clockwise into G1, S, G2 and M with each arc sized to how long the phase takes, bracket G1, S and G2 as interphase, branch G0 off G1 and mark the checkpoints at G1/S, G2/M and in metaphase. With this maker you describe the version you need and the circle is drawn in that order.
What are the phases of the cell cycle?
Interphase — G1, S and G2 — and the M phase, which is mitosis (prophase, prometaphase, metaphase, anaphase, telophase) followed by cytokinesis. Cells that stop dividing leave G1 for G0.
What happens during interphase?
The cell grows and copies its DNA: in G1 it grows and makes proteins and organelles, in S it replicates every chromosome into two sister chromatids and duplicates the centrosome, and in G2 it makes the proteins needed for mitosis. Interphase fills about 23.5 hours of a 24-hour human cycle; the G1/S checkpoint guards the step from G1 into S, and the G2/M checkpoint the step from G2 into mitosis.
Can I get a labeled cell cycle diagram and a blank one to label?
Yes — both are on this page free: the labeled cell cycle is the answer key and the blank one has an empty answer line for every phase, checkpoint and regulator. You can also generate a new pair at any level of detail.
What are the three cell cycle checkpoints?
The G1/S checkpoint (restriction point), the G2/M checkpoint and the spindle (M) checkpoint in metaphase. They check, in turn, whether conditions and the DNA are fit for replication, whether all DNA has been copied without damage, and whether every chromosome is attached to the spindle.
Which cyclin–CDK complexes control the cell cycle?
Cyclin D–CDK4/6 in G1, cyclin E–CDK2 at the G1/S transition, cyclin A–CDK2 during S phase and cyclin B–CDK1 at the G2/M transition. The CDK levels stay steady; the cyclin levels rise and fall, so each complex is active only in its window.
What is the G0 phase?
G0 is a resting state outside the cycle, where a cell does its job without preparing to divide. Some cells return to G1 when signaled; mature cardiac muscle and nerve cells stay in G0 permanently.
How long does each phase of the cell cycle last?
In rapidly dividing human cells with a 24-hour cycle, about 9 hours in G1, 10 in S, 4.5 in G2 and 0.5 in M. The cycle ranges from about eight minutes in early fruit-fly embryos to a lifetime spent in G0 for some human cells.
What do p53 and Rb do in the cell cycle?
Both are brakes that act mainly at the G1 checkpoint. p53 halts the cycle when it detects damaged DNA and switches on p21, which blocks cyclin–CDK complexes; Rb holds the transcription factor E2F until CDKs phosphorylate it, releasing E2F to start S phase.
What happens when cell cycle checkpoints fail?
Cells divide with damaged or wrongly separated chromosomes, and unchecked division is a route to cancer. Rb, p53 and p21 were all first found faulty in cancer cells, and TP53, the gene for p53, is mutated in more than half of human tumors.
Is the cell cycle the same as mitosis?
No. Mitosis is the division of the nucleus inside the M phase; the cell cycle also includes interphase, when the cell grows and copies its DNA. The comparison table above sets them side by side.
Sources
- The Cell Cycle — Biology 2e, section 10.2 — OpenStax
- Control of the Cell Cycle — Biology 2e, section 10.3 — OpenStax
- Cell Cycle, Mitotic (R-HSA-69278) — Reactome
- G1/S Transition (R-HSA-69206) — Reactome
Keep exploring
Our other diagram tools, and the guides behind them.
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