Photosynthesis and Cellular Respiration Notes

Key Concepts and Introduction

• The lecture will cover how humans impact photosynthesis and cellular respiration.
• Key Concepts:
  • Pigments
  • Light-dependent and light-independent reactions (photosynthesis steps)
  • Cellular respiration (Glycolysis, Krebs cycle, Electron transport system)
  • Aerobic vs. anaerobic respiration

Tentative Schedule

• Introduction: Today
• Light Reaction: Tomorrow
• Dark Reaction: Tuesday
• Quiz on Photosynthesis: Next week
• Cellular Respiration and Lab: Following weeks
• Unit Test: End of the month

Topic 1: Comparing Living Systems (Review)

• Objectives:
  • Describe differences between plant and animal cells.
  • Compare anabolic and catabolic metabolism.
  • Learn the structures of mitochondria and chloroplasts.

Energy Flow in the Biosphere

• Sunlight enters the environment; plants absorb 1-2% of incoming solar energy.
• Photosynthesis converts radiant energy into glucose.
• Animals consume glucose, turning it into ATP (usable energy).

Metabolism

• Photosynthesis:
  • Used by plants and other producers.
  • Traps radiant energy from the sun and converts it into chemical energy (glucose).
  • Occurs in chloroplasts (only in plant cells).
  • Anabolic pathway.
• Cellular Respiration:
  • Performed by plants, animals, and all living organisms with mitochondria.
  • Breaks down glucose to synthesize ATP (adenosine triphosphate).
  • Energy conversion process occurs in the mitochondria.
  • Catabolic pathway.
• ATP (Adenosine Triphosphate): An adenosine molecule with three phosphate molecules.

Anabolic vs. Catabolic Pathways

• Anabolic:
  • Synthesizes large molecules from smaller ones (e.g., glucose).
  • Requires energy (e.g., sun's energy).
• Catabolic:
  • Breaks down larger molecules into smaller ones.
  • Releases energy (used to synthesize ATP).

Cell Structures: Animal vs. Plant Cells

• Animal Cell:
  • Contains mitochondria, nucleus, endoplasmic reticulum (rough and smooth), Golgi apparatus, ribosomes, etc.
• Plant Cell:
  • Also contains the organelles found in animal cells.
  • Unique Structures:
    • Cell wall: Provides support.
    • Chloroplasts: Site of photosynthesis.
    • Large central vacuole: Stores water and nutrients.

Structure of the Chloroplast

• Membranes:
  • Outer membrane
  • Intermembrane space
  • Inner membrane
• Internal Structures:
  • Thylakoids: Flat discs where the first part of photosynthesis takes place.
    • Lumen: Fluid inside the thylakoid.
  • Granum (or Grana): Stacks of thylakoids (about 60).
  • Lamella: Connects granum like a bridge.
  • Stroma: Fluid surrounding the thylakoids.

Structure of the Mitochondria

• Evolved from a unicellular organism; has mitochondrial DNA passed down by the mother.
• Membranes:
  • Outer membrane (phospholipid bilayer)
  • Intermembrane space
  • Inner membrane (folds into the matrix)
• Internal Structures:
  • Matrix: Fluid-filled space inside the mitochondria (like the stroma in chloroplasts).
  • Cristae: Folds of the inner membrane, increasing surface area for ATP production.
  • Membrane Composition: Phospholipids, proteins, carbohydrates.

Organic vs. Inorganic Compounds

• Organic Compounds:
  • Derived from living organisms.
  • Contain carbon-hydrogen covalent bonds.
  • Examples: CO_2, excrement, leaves.
  • Covalent bonds: Sharing of electrons.
• Inorganic Compounds:
  • Derived from nonliving components.
  • Generally lack carbon or carbon-hydrogen bonds.
  • Have ionic bonds from other elements.
  • Ionic bonds: Transfer of electrons between a metal and a nonmetal.
    • Ionic bonds are stronger than covalent bonds.

Unique Organisms

• Green Sea Slug: An animal that can perform photosynthesis.