Cell Components and Their Functions

Cell Structures

Cell Membrane

• Flexible covering
• Protects inside of cell from external environment
• Made of proteins and phospholipids

Cell Wall

• Stiff structure outside the cell membrane
• Provides protection from viruses and harmful organisms
• Maintains cell shape and offers structural support

Cytoplasm

• Fluid inside a cell
• Contains salts, molecules, and the cytoskeleton

Cytoskeleton

• Network of threadlike proteins
• Maintains animal cell shape
• Aids in cell movement
• Composed of proteins forming cilia and flagella

Organelles

Nucleus

• Directs cell activities
• Contains DNA organized into chromosomes

Nucleolus

• Located within the nucleus
• Produces ribosomes

Chloroplast

• Membrane-bound organelles
• Uses light energy to produce glucose from water and carbon dioxide
• Site of photosynthesis (only in plant cells)

Golgi Apparatus

• Prepares proteins for specific functions
• Packages proteins into vesicles

Ribosomes

• Located in cytoplasm
• Produce proteins by reading mRNA
• Link amino acids

Endoplasmic Reticulum (ER)

• Extends from nucleus through cytoplasm
• Rough ER: Has ribosomes, site of protein production
• Smooth ER: Produces lipids, removes harmful substances

Vesicles

• Transport substances within the cell
• Includes lysosomes (in animal cells) for breaking down and recycling components

Vacuoles

• Store food, water, and waste

Flagella

• Long tail-like appendages for cell movement

Cilia

• Short hairlike structures
• Can move cells or substances past cell surface

Cell Types

Eukaryotic Cells

• Found in plants, animals, and protists
• Contain organelles and a cell membrane
• Larger than prokaryotic cells

Prokaryotic Cells

• Unicellular organisms (prokaryotes)
• Lack membrane-bound organelles

Comparison between Animal and Plant Cells

1. Shape:

   • Plant cell shape maintained by cell wall
   • Animal cell shape maintained by cytoskeleton

2. Organelles:

   • Plant cells have chloroplasts and a large central vacuole
   • Animal cells have lysosomes and many smaller vacuoles

3. Common Features:

   • Both are made of eukaryotic cells
   • Contain a nucleus and Golgi apparatus