2.2 - Cell Structure and Function

The Relationship Between Form and Function in Cellular Components

• Principle of Form Meets Function: Each subcellular component is designed to optimize its specific function within the cell.

• Key Cellular Components and Their Functions:

  • Lysosomes: These organelles digest molecules and recycle cellular materials, clearing the cell of old or damaged components.

  • Endoplasmic Reticulum (ER):

    • Functions in the synthesis of proteins and lipids, which are crucial for various cellular processes.

    • Transports these molecules throughout the cell and provides structural support.

  • Vacuoles: Serve primarily to store molecules, waste products, and regulate water content within the cell, crucial for maintaining cell structure and function.

• Mitochondria

  • Engage in metabolic reactions, crucial for ATP synthesis, the cell’s energy currency.

  • Contain their own DNA and ribosomes, suggesting a degree of autonomy within the cell.

  • Specific Processes in Mitochondria:

    • Aerobic Cellular Respiration: Takes place entirely within mitochondria.

    • Oxidative Phosphorylation: Occurs along the inner membrane, utilizing the electron transport chain.

    • Krebs/Citric Acid Cycle: Occurs in the mitochondrial matrix, a key step in energy production.

• Chloroplasts: Essential for photosynthesis in plants and algae.

• Contain an intricate inner membrane system, the site of photosynthesis.

• Photosynthetic Processes in Chloroplasts:

  • Light-Dependent Reactions: Occur in the thylakoid membranes within the grana; these reactions capture solar energy.

  • Calvin Cycle (Dark Reactions): Takes place in the stroma and does not require light, focusing on sugar synthesis.

  • Thylakoid membranes are enriched with chlorophyll and proteins essential for the photosystem, enabling energy capture and conversion.