Cells are the foundation of all living organisms, from microscopic bacteria to complex human bodies. Unit 2 of AP Biology dives deep into the structure and function of cells, examining their organelles, transport mechanisms, and communication pathways. Understanding these concepts is crucial for grasping how life operates at the cellular level.
Study Guides for Unit 2
Comprehensive Breakdown:
- 2.0 – Unit Overview: Cell Structure and Function (5 min read)
- 2.1 – Cell Structure: Subcellular Components (6 min read)
- 2.2 – Cell Structure and Function (3 min read)
- 2.3 – Cell Size (2 min read)
- 2.4 – Plasma Membranes (3 min read)
- 2.5 – Membrane Permeability (2 min read)
- 2.6 – Membrane Transport (3 min read)
- 2.7 – Facilitated Diffusion (3 min read)
- 2.8 – Tonicity and Osmoregulation (4 min read)
- 2.9 – Mechanisms of Transport (6 min read)
- 2.10 – Cell Compartmentalization (2 min read)
- 2.11 – Origins of Cell Compartmentalization (2 min read)
Key Concepts You Need to Know
✅ Cell Theory – All living organisms are composed of cells, the basic unit of life. ✅ Prokaryotic vs. Eukaryotic Cells – Understanding their structural differences. ✅ Cell Membrane & Transport – How the phospholipid bilayer regulates movement. ✅ Organelles & Their Functions – The nucleus, mitochondria, ribosomes, ER, Golgi apparatus, lysosomes, and chloroplasts. ✅ Energy Production – Cellular respiration and photosynthesis mechanisms. ✅ Cell Communication – Signaling pathways and intercellular interactions.
Cell Theory and Discovery
- Developed by Schleiden, Schwann, and Virchow in the 19th century.
- Microscope advancements by Leeuwenhoek and Hooke led to the discovery of cells.
- Modern microscopy techniques provide deeper insights into cellular functions.
Types of Cells
- Prokaryotic Cells – Simple structure, no nucleus, found in bacteria and archaea.
- Eukaryotic Cells – More complex, with membrane-bound organelles, found in animals, plants, fungi, and protists.
Cell Membrane Structure & Transport Mechanisms
- Diffusion & Osmosis – Passive transport methods.
- Facilitated Diffusion – Requires transport proteins.
- Active Transport – Uses ATP to move molecules against a concentration gradient.
- Endocytosis & Exocytosis – Bulk transport mechanisms for large molecules.
Energy Production in Cells
- Cellular Respiration – Glycolysis, Krebs cycle, and Electron Transport Chain.
- Photosynthesis – Light-dependent reactions and Calvin cycle in chloroplasts.
Cell Communication & Signaling
- Ligand-receptor interactions – Crucial for cell communication.
- Signal Transduction Pathways – G-protein coupled receptors (GPCRs), receptor tyrosine kinases (RTKs), and intracellular receptors.
- Gap Junctions & Plasmodesmata – Direct cell-to-cell communication.
Practical Applications
- Medicine – Targeted drug delivery and genetic engineering.
- Biotechnology – CRISPR gene editing and synthetic biology.
- Agriculture – Genetically modified crops for higher yield and resistance.
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