Learn on PengiLife Science (Grade 7)Chapter 3: Cell Division

Lesson 1: Cell division occurs in all organisms.

Normally spread throughout the nucleus, DNA wraps around proteins and condenses into chromosomes before cell division. Each species has a specific number of chromosomes, like humans with 46.

Section 1

DNA Compacts Into Visible Chromosomes

Normally spread throughout the nucleus, DNA wraps around proteins and condenses into chromosomes before cell division. Each species has a specific number of chromosomes, like humans with 46.

Section 2

Cells Divide to Support Growth and Development

Multicellular organisms grow through cell division, increasing cell numbers rather than cell size. As development continues, cells become specialized for specific functions while maintaining the same genetic material.

Section 3

Cell Division Repairs Damaged Tissues

When injuries occur, healthy cells divide rapidly to replace damaged ones. Different tissues heal at varied rates—skin cells replace about 40,000 cells per minute, while brain cells divide much less frequently.

Section 4

Scientists Discover Nerves Regenerate in Adults

Using a chemical dye called BrdU, researchers found that new nerve cells can grow in adult brains, contradicting previous beliefs. This discovery offers hope for treating nervous system damage and diseases.

Book overview

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Chapter 3: Cell Division

  1. Lesson 1Current

    Lesson 1: Cell division occurs in all organisms.

  2. Lesson 2

    Lesson 2: Cell division is part of the cell cycle.

  3. Lesson 3

    Lesson 3: Both sexual and asexual reproduction involve cell division.

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

DNA Compacts Into Visible Chromosomes

Normally spread throughout the nucleus, DNA wraps around proteins and condenses into chromosomes before cell division. Each species has a specific number of chromosomes, like humans with 46.

Section 2

Cells Divide to Support Growth and Development

Multicellular organisms grow through cell division, increasing cell numbers rather than cell size. As development continues, cells become specialized for specific functions while maintaining the same genetic material.

Section 3

Cell Division Repairs Damaged Tissues

When injuries occur, healthy cells divide rapidly to replace damaged ones. Different tissues heal at varied rates—skin cells replace about 40,000 cells per minute, while brain cells divide much less frequently.

Section 4

Scientists Discover Nerves Regenerate in Adults

Using a chemical dye called BrdU, researchers found that new nerve cells can grow in adult brains, contradicting previous beliefs. This discovery offers hope for treating nervous system damage and diseases.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 3: Cell Division

  1. Lesson 1Current

    Lesson 1: Cell division occurs in all organisms.

  2. Lesson 2

    Lesson 2: Cell division is part of the cell cycle.

  3. Lesson 3

    Lesson 3: Both sexual and asexual reproduction involve cell division.