Cellular Structure, Organelles & Membrane Transport

The cell is the fundamental membrane-bound unit of living organisms.

• Prokaryotes vs Eukaryotes: Prokaryotes (e.g. Bacteria) lack a membrane-enclosed nucleus and membrane-bound organelles, possessing 70S ribosomes and circular DNA. Eukaryotes possess 80S ribosomes and linear chromosomes.
• Passive Transport: Simple diffusion and facilitated diffusion (via channel/carrier proteins) down concentration gradients without ATP.
• Active Transport: Primary active transport (e.g. Na+/K+ ATPase pump) moves ions against gradients using ATP hydrolysis.
• Mitochondria: Double-membrane organelles housing the Krebs cycle in the matrix and oxidative phosphorylation on inner cristae folds.

1. Differentiate prokaryotic cellular features from eukaryotic organelles.
2. Identify whether transport processes require cellular energy (ATP) or carrier proteins.
3. Match cellular organelles (Lysosomes, Golgi, Endoplasmic Reticulum) to metabolic roles.