SPM Biology 2 Cell Biology & Organization Part 4 - Living Processes in Multicellular Organisms

There are various types of cells in multicellular organisms which are different in:

• size
• shape
• arrangement

Each type of cell is specialized to carry out a specific function.

Specialized cells found in humans

White blood cell

1. White blood cell

• Various shape
• Function: Destroy pathogen

Red blood cell

2. Red blood cell

• X nucleus
• Shape: biconcave disc
• Function: Transport oxygen

Epithelial cell

 3. Epithelial cell

• Thin, flat
• Coats the surface of organs

Muscle cell

4. Muscle cell

• Arranged as multinuclear striated fibers
• Function: Generate movement

Nerve cell

5. Nerve cell

• Long, thin
• Function: Sending nerve impulses

Sperm cell

6. Sperm cell

• Has long tail 
• Head carries chromosomes from the male 

Specialized cells found in plants

Root hair cell

1. Root hair cell

• Long
• Function: Absorb water and mineral salts

Xylem vessel

2. Xylem vessel

• Long, continuous hollow tube
• Function: Transport water and mineral salts from roots to other parts of the plant

Sieve tube element

3. Sieve tube element

• Long cylindrical tubes
• Function: Transport organic materials from leaves to storage organs (fruits etc.)

Palisade mesophyll cell & Spongy mesophyll cell

4. Palisade mesophyll cell

• Long cylindrical cells 
• Function: Absorb sunlight for photosynthesis 

5. Spongy mesophyll cell 

• Cells arranged with lots of air space in between
• Function: Allow gases exchange from inside of the leave to palisade mesophyll cells

Guard cell

6. Guard cell

• Modified lower epidermal cells with thicker cell wall on inner side
• Function: Controls opening and closing of stoma (the opening that allows exchange of oxygen and carbon dioxide)