Specialized Plant Cells

Introduction

• Goal: Describe how root hair cells, xylem cells, and phloem cells are specialized for their functions.
• Concept: Specialization in plant cells, known as differentiation, involves developing adaptations for specific functions.

General Plant Cell Structures

• Key Structures:
  • Chloroplasts
  • Cellulose cell wall
  • Permanent vacuole

Specialized Plant Cells

Root Hair Cells

• Function: Increase surface area for absorption of water and minerals.
• Structure:
  • Hair-like projections that increase surface area.
  • Lack chloroplasts because they are underground and do not perform photosynthesis.

Xylem Cells

• Function: Transport water and dissolved minerals from roots to leaves.
• Structure:
  • Form long tubes in the plant stem.
  • Thick walls containing lignin for support, causing cells to die.
  • End walls broken down to form a continuous tube for easier flow.
  • Lack internal structures such as nucleus, cytoplasm, vacuole, or chloroplasts.

Phloem Cells

• Function: Transport dissolved sugars up and down the plant.
• Structure:
  • Consist of phloem vessel cells and companion cells.
  • Phloem vessel cells have limited cytoplasm and lack a nucleus.
  • End walls have pores called sieve plates to allow sugar flow.
  • Companion cells connected by pores provide energy via mitochondria.

Review and Application

• Refer to the vision workbook for practice questions on specialized plant cells.

Conclusion

• Successfully describe how root hair cells, xylem cells, and phloem cells are specialized for their respective functions.