Cell Structure and Function

Cell Structure

Cell Membrane

• Semipermeable: allows certain substances to pass through while keeping others out
• Phospholipid bilayer: composed of two layers of phospholipid molecules with hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails
• Functions:
  • Controls what enters and leaves the cell
  • Provides structural support and maintains cell shape
  • Regulates cell signaling and communication

Organelles

Types of Organelles

• Membrane-bound organelles:
  • Have a distinct membrane separating them from the rest of the cell
  • Examples: nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus
• Non-membrane-bound organelles:
  • Lack a distinct membrane
  • Examples: ribosomes, cytoskeleton

Organelle Functions

• Nucleus:
  • Controls cell growth and division
  • Contains genetic material (DNA)
• Mitochondria:
  • Generates energy for the cell through cellular respiration
  • Converts glucose into ATP
• Endoplasmic Reticulum (ER):
  • Synthesizes and transports proteins and lipids
  • Two types: rough ER (with ribosomes) and smooth ER (without ribosomes)
• Golgi Apparatus:
  • Modifies and packages proteins and lipids for transport
  • Forms lysosomes and secretory vesicles
• Ribosomes:
  • Site of protein synthesis
  • Found throughout the cytoplasm and attached to ER
• Cytoskeleton:
  • Provides structural support and shape to the cell
  • Involved in cell movement and division

Cell Structure

• Cell membrane is semipermeable, allowing certain substances to pass through while keeping others out.
• Phospholipid bilayer structure: two layers of phospholipid molecules with hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails.
• Cell membrane functions: controls what enters and leaves the cell, provides structural support and maintains cell shape, and regulates cell signaling and communication.

Organelles

Types of Organelles

• Membrane-bound organelles: have a distinct membrane separating them from the rest of the cell.
• Examples of membrane-bound organelles: nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus.
• Non-membrane-bound organelles: lack a distinct membrane.
• Examples of non-membrane-bound organelles: ribosomes, cytoskeleton.

Organelle Functions

• Nucleus functions: controls cell growth and division, contains genetic material (DNA).
• Mitochondria functions: generates energy for the cell through cellular respiration, converts glucose into ATP.
• Endoplasmic Reticulum (ER) functions: synthesizes and transports proteins and lipids, has two types: rough ER (with ribosomes) and smooth ER (without ribosomes).
• Golgi Apparatus functions: modifies and packages proteins and lipids for transport, forms lysosomes and secretory vesicles.
• Ribosomes functions: site of protein synthesis, found throughout the cytoplasm and attached to ER.
• Cytoskeleton functions: provides structural support and shape to the cell, involved in cell movement and division.