Specialized Cell Types

This section examines several types of specialized cells and their adaptations for specific functions.

Palisade Cell

Palisade cells are specialized plant cells found in leaves.

Function: Carry out photosynthesis at the top of a leaf

Adaptations:

• Large surface area to maximize light absorption

Ciliated Cell

Ciliated cells are found in the respiratory tract.

Function: Sweep mucus containing trapped dust and germs

Adaptations:

• Thin layer of hair-like projections called cilia on the cell surface

Root Hair Cell

Root hair cells are specialized plant cells found in roots.

Function: Absorption of water and mineral ions from soil

Adaptations:

• Finger-like projections to increase surface area for absorption
• Large permanent vacuole to speed up water movement by osmosis
• Mitochondria for active transport of mineral ions

Example: Root hair cells lack chloroplasts since they are underground where there is no light for photosynthesis.

Bacterial Cell

The guide provides a labeled diagram of a bacterial cell, highlighting its prokaryotic structure.

Highlight: Bacterial cells lack a nucleus and instead contain chromosomal DNA and plasmids with genes.

Key features of bacterial cells include:

• Cell membrane
• Cell wall
• Capsule
• Flagellum
• Chromosomal DNA
• Plasmid DNA

This section effectively illustrates the 10 difference between prokaryotic and eukaryotic cell structure through the comparison of bacterial and plant/animal cells.

Muscle Cell Structure

The final section examines the structure of muscle cells.

Function: Contract and relax to produce movement

Adaptations:

• Contain special proteins that slide over each other, enabling contraction
• Numerous mitochondria to provide energy for contraction
• Multiple nuclei to control the large cell volume

Example: The sliding filament model explains how the arrangement of actin and myosin proteins allows muscle cells to contract.

This section effectively illustrates how the structure of specialized cells in plants and animals is tailored to their specific functions within organisms. The detailed explanations and labeled diagrams provide a comprehensive overview of cell structure and function for students studying biology at the GCSE and class 9 levels.