Cell Biology Fundamentals

Cellular Components

• Plasma Membrane:
  • Semi-permeable membrane separating cell from environment
  • Regulates what enters and leaves the cell
  • Composed of phospholipid bilayer with embedded proteins
• Cytoplasm:
  • Jelly-like substance inside the plasma membrane
  • Site of metabolic reactions and protein synthesis
  • Contains various organelles
• Organelles:
  • Nucleus: contains DNA, controls cell growth and division
  • Mitochondria: generates energy for the cell through cellular respiration
  • Endoplasmic Reticulum (ER): synthesizes and transports proteins and lipids
  • Ribosomes: site of protein synthesis
  • Lysosomes: contains digestive enzymes, breaks down and recycles cellular waste
  • Golgi Apparatus: modifies, packages, and transports proteins and lipids

Cellular Processes

• Cell Signaling:
  • Process by which cells respond to stimuli
  • Involves reception, transduction, and response to signals
• Cell Division:
  • Mitosis: process of cell division resulting in two daughter cells
  • Meiosis: process of cell division resulting in four daughter cells with half the number of chromosomes
• Cell Transport:
  • Passive Transport: movement of molecules from high to low concentration without energy input
  • Active Transport: movement of molecules against concentration gradient using energy
• Metabolism:
  • Catabolism: breakdown of molecules to release energy
  • Anabolism: synthesis of molecules using energy

Cellular Regulation

• Cell Cycle Regulation:
  • Checkpoints: ensure proper progression through cell cycle
  • Cyclin-dependent kinases (CDKs): regulate progression through cell cycle
• Apoptosis: programmed cell death, eliminates damaged or unwanted cells
• Cell-Cell Interactions:
  • Adhesion: cells stick together through adhesion molecules
  • Signaling: cells communicate through signaling molecules

Cellular Response to Stimuli

• Stress Response:
  • Cellular response to stress, including heat shock proteins
• Inflammation:
  • Response to tissue damage or infection, involving immune cells and chemical signals