The Living World: Senior Cycle Biology · 5th Year

Active learning ideas

How Cells Grow and Divide (Simple Concept)

Growth and division in cells is invisible to the naked eye, making abstract ideas feel distant for students. Active learning lets learners manipulate models, observe real cells, and track changes over time, turning mitosis from a memorized term into a process they can visualize and explain in their own words.

• NCCA Curriculum Specifications
• NCCA: Primary Curriculum - Science - Living Things - Human Life
• NCCA: Primary Curriculum - Science - Living Things - Plant and Animal Life

• 25–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• 30 min · Pairs

Modeling Lab: Clay Cell Division

Provide pairs with colored clay to represent chromosomes. Students shape a parent cell, then pinch and separate it into two identical daughter cells, labeling stages like prophase and telophase. Discuss how this mirrors growth in their bodies.

How do we grow bigger?

Facilitation Tip

During the Clay Cell Division activity, circulate with a checklist to note which students can accurately model each stage of mitosis using their clay cells.

What to look for

Provide students with two scenarios: 1) a child growing taller, and 2) a cut healing on an arm. Ask them to write one sentence for each scenario explaining how cell division contributes to the outcome.

Activity 02

• 45 min · Small Groups

Microscope Stations: Onion Root Tips

Prepare slides of onion root tips stained to show dividing cells. Small groups rotate through stations, sketching stages of mitosis and noting cell size changes. Conclude with a class chart comparing observed cells to drawings.

What happens when we get a cut or scrape?

Facilitation Tip

At the Microscope Stations, remind students to sketch and label at least three different stages of cell division they observe in the onion root tip slides.

What to look for

Display images of a growing seedling, a healing cut, and a diagram of mitosis. Ask students to verbally identify which image relates to growth, which to repair, and which shows the cellular process, explaining their reasoning.

Activity 03

• 50 min · Pairs

Inquiry Track: Wound Healing Observation

Students in pairs cut a potato slice, observe cell division over days under a hand lens, and record changes in a journal. Compare to personal scrape healing stories shared in whole class debrief.

Why do plants grow new leaves?

Facilitation Tip

During the Wound Healing Observation, encourage students to compare their initial and final plant cuttings, prompting them to describe visible changes in terms of cell division.

What to look for

Pose the question: 'Why is it important that cell division is a controlled process?' Facilitate a class discussion, guiding students to consider what might happen if cells divided too quickly or too slowly.

Activity 04

• 25 min · Whole Class

Whole Class Demo: Yeast Budding

Project live yeast cells budding under microscope as a model of cell division. Students predict, observe, and vote on sketches of stages via interactive board, linking to plant and animal growth.

How do we grow bigger?

Facilitation Tip

In the Yeast Budding demo, pause to ask students to predict how the number of yeast cells will change over time before they observe the results.

What to look for

Provide students with two scenarios: 1) a child growing taller, and 2) a cut healing on an arm. Ask them to write one sentence for each scenario explaining how cell division contributes to the outcome.

A few notes on teaching this unit

Teachers often start with the concept of growth to hook students, then move to repair to broaden their understanding beyond textbook definitions. Avoid rushing to label stages of mitosis; instead, let students discover patterns in dividing cells through guided observations. Research shows that students grasp mitosis better when they connect it to familiar contexts, so emphasize the

By the end of these activities, students should confidently describe how cell division supports growth and repair, use microscopes to identify dividing cells, and connect their observations to everyday experiences like healing or plant growth. Success looks like students explaining the difference between growth and repair using evidence from their work.

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Watch Out for These Misconceptions

• During the Clay Cell Division activity, watch for students who model only cell enlargement and skip the division step entirely, indicating they believe organisms grow by cells getting bigger alone.

  Prompt students to compare their initial clay cell with the final product, asking them to point out where the 'original' cell split into two. Have peers explain how the clay model of division matches the growth of larger organisms, like a child getting taller.

• During the Microscope Stations activity, listen for students who assume all visible cell divisions are related to reproduction, even when observing root tip cells.

  Ask students to recall the purpose of root tips (growth toward water and nutrients) and compare that to where reproductive cells are found in plants. Have them discuss as a group how the context of their observations changes the meaning of 'division.'

• During the Wound Healing Observation activity, note students who assume all cells divide at the same rate because their plant cuttings seem to change uniformly.

  Guide students to compare the rate of change in the cuttings to the rate of repair in their own skin. Ask them to brainstorm why some tissues might need faster or slower division, referencing their journal observations.