Cell Biology Study Notes

Cell Biology Study Notes

Cell Theory

• All living organisms are composed of cells.
• The cell is the basic unit of life.
• All cells arise from pre-existing cells.

Types of Cells

1. Prokaryotic Cells

   • Lack a nucleus and membrane-bound organelles.
   • Smaller and simpler (e.g., bacteria).
   • Genetic material is in the nucleoid region.

2. Eukaryotic Cells

   • Contain a nucleus and membrane-bound organelles.
   • Larger and more complex (e.g., plants, animals, fungi, protists).
   • DNA is linear and associated with histones.

Cell Structure

• Cell Membrane

  • Phospholipid bilayer that controls the movement of substances in and out.
  • Contains proteins, cholesterol, and carbohydrates.

• Nucleus

  • Contains genetic material (DNA).
  • Surrounded by the nuclear envelope.
  • Site of transcription and ribosome assembly.

• Organelles

  • Mitochondria: Powerhouse of the cell, site of ATP production.
  • Ribosomes: Protein synthesis.
  • Endoplasmic Reticulum (ER)
    • Rough ER: Studded with ribosomes, involved in protein synthesis.
    • Smooth ER: Synthesizes lipids and detoxifies substances.
  • Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
  • Lysosomes: Contains digestive enzymes for waste processing.
  • Peroxisomes: Break down fatty acids and detoxify harmful substances.

Cell Division

• Mitosis: Process of somatic cell division resulting in two identical daughter cells.
  • Phases: Prophase, Metaphase, Anaphase, Telophase.
• Meiosis: Process of gamete formation resulting in four genetically diverse cells.
  • Involves two rounds of division (Meiosis I and II).

Cellular Respiration

• Process by which cells convert glucose and oxygen into ATP, carbon dioxide, and water.
• Three stages:
  1. Glycolysis (cytoplasm)
  2. Krebs Cycle (mitochondria)
  3. Electron Transport Chain (mitochondria)

Photosynthesis

• Process by which plants, algae, and some bacteria convert light energy into chemical energy.
• Occurs in chloroplasts.
• Two main stages:
  1. Light-dependent reactions: Convert sunlight into ATP and NADPH.
  2. Calvin Cycle: Utilizes ATP and NADPH to synthesize glucose.

Cell Communication

• Signal Transduction Pathways
  • Series of molecular events triggered by a signal that leads to a cellular response.
  • Includes: Reception, Transduction, Response.

Stem Cells

• Undifferentiated cells with the potential to develop into various cell types.
• Types:
  • Embryonic Stem Cells: Pluripotent, can give rise to any cell type.
  • Adult Stem Cells: Multipotent, limited to certain cell types.

Biotechnology Applications

• Genetic engineering, CRISPR, cloning, and regenerative medicine.

These notes summarize key concepts in Cell Biology relevant to Biology Honors coursework.