Lecture Notes: Prokaryotic vs Eukaryotic Cells

Overview

• Eukaryotic Cells: Cells with a nuclear membrane and organelles (plants, animals, fungi, protists).
  • Have a nuclear membrane and organelles.
  • Can be unicellular or multicellular.
  • DNA stored in the nucleus.
• Prokaryotic Cells: Cells without membrane-bound organelles (bacteria, archaea).
  • Simpler, mostly unicellular.
  • DNA stored in the cytoplasm, non-chromosomal DNA in plasmids.

Key Differences

• Eukaryotic Cells
  • Complex structure.
  • Membrane-bound organelles.
  • DNA within a nucleus.
• Prokaryotic Cells
  • Simpler structure.
  • No membrane-bound organelles or nucleus.
  • Free-floating DNA.

Similarities

• Both have DNA, cell membrane, and cytoplasm.

Cell Organelles and Functions

• Nucleus: Stores genetic material, coordinates cell activities (growth, protein synthesis, cell division).
• Ribosomes: Site of protein synthesis, found on rough ER.
• Endoplasmic Reticulum (ER)
  • Rough ER: Transports proteins produced by ribosomes.
  • Smooth ER: Synthesizes phospholipids.
• Golgi Apparatus: Modifies and packages proteins into vesicles.
• Lysosomes: Digest unwanted materials.
• Vacuoles: Provide structural support in plants, involved in storage and waste disposal.
• Plastids: Involved in synthesis and storage, not found in animals.
• Cell Wall: Provides structure in plants.
• Cytoskeleton: Supports cell structure and movement.
• Centrioles: Involved in cell division.
• Cilia and Flagella: Involved in cell movement.

Energy Transformation

• Mitochondria: Powerhouse of the cell, converts energy from food into usable energy.
• Chloroplasts: Involved in photosynthesis, trap light energy.

Cellular Processes

• Cellular Respiration
  • Aerobic Respiration: Occurs with oxygen, produces 36 ATP.
  • Anaerobic Respiration: Occurs without oxygen, produces 2 ATP.
• Photosynthesis
  • Light-dependent stage (Photolysis) occurs in the Grana.
  • Light-independent stage (Carbon fixation) occurs in the Stroma.

Movement of Materials

• Passive Movement
  • Diffusion: Movement from high to low concentration until equilibrium.
  • Osmosis: Movement of water across a semi-permeable membrane.
  • Concentration Gradient: Passive movement of substances.
• Active Movement
  • Requires ATP to move substances against the concentration gradient.
  • Endocytosis: Membrane engulfs particles into the cell.
  • Exocytosis: Vesicles release contents out of the cell.

Enzyme Models

• Lock and Key Model: Substrate fits into the enzyme like a key in a lock.
• Induced Fit Model: Substrate binding induces the enzyme to change shape.

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This concludes the overview of Module 1, covering the structure and function of cells, cellular processes, and movement of materials.