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Introduction to Cell Division: How Living Things Grow and Heal

Lesson Plan · Grade 1 · English

Introduction to Cell Division: How Living Things Grow and Heal

Standards Addressed

Next Generation Science Standards (NGSS)

  • 1-LS1-1 From Molecules to Organisms: Structures and Processes
  • Core Concept: Living things have internal and external structures that function to support survival, growth, and repair.
  • Application: Students observe and explain how the body uses tiny building blocks (cells) to add tissue for growth and heal minor skin injuries.
  • 1-LS3-1 Heredity: Inheritance and Variation of Traits
  • Core Concept: Young organisms and newly formed structures resemble their origins.
  • Application: Students recognize that when cells divide, the new cells are identical copies that look and act like the original cell.

Disciplinary Core Ideas (DCI)

  • LS1.A: Structure and Function: All organisms are made of parts that help them survive and grow.
  • LS1.B: Growth and Development of Organisms: Organisms reproduce and grow by generating new parts and tissues.

Crosscutting Concepts (CCC)

  • Patterns: Identifying consistent patterns in growth—growth happens by adding more parts (cells), not merely expanding a single part.
  • Structure and Function: Understanding that microscopic cells serve as the fundamental structural units that build tissues and skin.

Science and Engineering Practices (SEP)

  • Developing and Using Models: Using simple physical representations (e.g., playdough or building blocks) to model how one starting unit splits to become two identical units.
  • Constructing Explanations: Explaining in age-appropriate terms how a scrape on the knee disappears as new skin cells form.


Key Concepts

1. Living Things Are Made of Cells

  • All living organisms—humans, animals, trees, and flowers—are made of microscopic building blocks called cells.
  • Cells are so small that they can only be seen with a microscope, but billions of them work together to make up our skin, bones, muscles, and organs.

2. How Living Things Grow

  • Living things do not grow simply by cells expanding like giant balloons.
  • Instead, growth happens because our bodies make more cells.
  • As babies grow into children and children grow into adults, their total number of cells increases.

3. Understanding Cell Division (Mitosis)

  • One Becomes Two: A single cell grows slightly, copies its instructions, and pinches in the middle until it splits into two separate cells.
  • Identical Twins: The two new cells are exact copies of the original cell. A skin cell divides to make another skin cell; a bone cell divides to make another bone cell.
  • Continuous Cycle: This process repeats over and over as the organism develops.

4. Healing and Body Repair

  • When you get a scrape, cut, or scratch, skin cells are damaged or lost.
  • The healthy cells surrounding the cut begin dividing to make fresh, new cells.
  • Over several days, these new cells fill the gap and create a smooth layer of new skin.

5. Core Vocabulary

  • Cell: A tiny living building block that makes up all plants and animals.
  • Divide: To split apart. In cell division, one cell splits into two new cells.
  • Grow: To get taller or bigger by creating more cells.
  • Heal: To repair a hurt or damaged part of the body using brand-new cells.

Cells and Growth Quiz

Multiple Choice Questions

  1. What are the tiny living building blocks that make up all people, animals, and plants?
  • A) Cells
  • B) Rocks
  • C) Toys
  1. How do living things grow bigger?
  • A) Their cells stretch out like balloons
  • B) Their cells divide to make more cells
  • C) Their cells disappear
  1. When one cell divides, how many cells does it become?
  • A) Zero
  • B) Five
  • C) Two
  1. What happens when you scrape your knee?
  • A) Your body loses all its cells
  • B) Healthy skin cells divide to heal the scrape
  • C) The scrape turns into a bone
  1. When a skin cell divides, what does the new cell look like?
  • A) An exact copy of the skin cell
  • B) A plant leaf cell
  • C) Something completely different