Understanding Cell Structure and Function

Aug 30, 2024

Lecture Notes: Chapter 3 - Cell Structure and Function

Overview

  • Focus on the structure and function of cells.
  • Importance in understanding organs and organ systems.

Cell Membrane

  • Definition: Protective outer layer of the cell.
  • Composition:
    • Phospholipids: Form a bilayer with hydrophilic heads and hydrophobic tails.
    • Cholesterol: Provides structure and support.
    • Proteins: Transmembrane proteins, glycoproteins, etc.

Functions of the Cell Membrane

  • Selectively permeable to certain substances.
  • Maintains concentration and electrical gradients.
  • Acts as a physical barrier.
  • Facilitates communication between cells.

Intracellular Environment

  • Cytosol: Fluid inside cells.
  • Cytoplasm: Includes cytosol, organelles, and inclusions.

Organelles

  • Mitochondria: Powerhouse, produces ATP, has its own DNA.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Protein synthesis, has ribosomes.
    • Smooth ER: Lipid synthesis, lacks ribosomes.
  • Golgi Apparatus: Modifies and packages proteins for secretion.
  • Nucleus: Contains DNA in the form of chromatin.

Other Cell Components

  • Ribosomes: Protein synthesis.
  • Cytoskeleton: Provides structural support.
  • Inclusions: Glycogen, lipid droplets, etc.

Cell Surface Structures

  • Cilia: Moves fluid across cell surfaces.
  • Flagella: Propels cells (e.g., sperm).
  • Microvilli: Increases surface area for absorption.

Cell Junctions

  • Gap Junctions: Allow communication and substance exchange between cells.
  • Tight Junctions: Prevent passage of substances between cells.
  • Anchoring Junctions: Provide structural support.

Cell Function and Processes

  • Protein Synthesis: Initiated in the nucleus and completed in the cytoplasm.
  • Secretion: Involves the Golgi apparatus and secretory vesicles.
  • Apoptosis: Programmed cell death to prevent damage from necrosis.

Additional Concepts

  • Stem Cells: Have the ability to divide and differentiate.
  • Research Implications: Potential for regenerative medicine.

Reminder: Always relate how cellular structures and functions connect with larger biological systems and processes.