VH

Photosynthesis and Cellular Respiration Notes

Unit C: Photosynthesis & Cellular Respiration

Introduction: Comparing Living Systems

  • The unit will cover photosynthesis and cellular respiration.

Index

  • Topics include introduction comparing living systems, photosynthesis (C1), and cellular respiration (C2).

Lesson 1: Photosynthesis and Cellular Respiration Review

  • The lesson will address the following questions:
    1. What are the differences between plant and animal cells?
    2. What is energy and ATP?
    3. What is the structure of a plant cell? Where does photosynthesis occur?

Energy Flow

  • All organisms need energy to live.
  • First law of thermodynamics: energy cannot be created or destroyed.
  • Energy can be converted into different forms.

Energy Transformation

  • Radiant energy from the sun is converted into usable energy by living things.

Photosynthesis

  • Producers (plants, algae, and some bacteria) convert radiant energy from the sun into chemical energy through photosynthesis.
  • Chemical energy is stored in the bonds of carbohydrate molecules, specifically glucose.

Cellular Respiration

  • Consumers convert the chemical energy stored in glucose into ATP through cellular respiration.
  • ATP is the body’s main fuel source.
  • ATP is “burned” to power cellular processes, transforming it into kinetic and thermal energy.

ATP

  • When energy is needed at the cellular level:
    • Adenosine triphosphate (ATP) - high energy molecule.
    • Is converted into adenosine diphosphate (ADP) - a low energy molecule.

Cycling of Energy

  • Photosynthesis:
    • Requires carbon dioxide and water.
    • Uses energy from the sun.
    • Produces oxygen and glucose.
  • Cellular Respiration:
    • Requires oxygen and glucose.
    • Releases carbon dioxide and water.
    • Makes energy available for cellular tasks in all organisms.

Animal Cells vs. Plant Cells

  • Lists organelles present in both animal and plant cells, highlighting differences.

Recall: Plant Cell

  • The chloroplast is responsible for photosynthesis.

Recall: Animal Cell

  • The mitochondria are responsible for cellular respiration.

Animal Cells vs. Plant Cells - Mitochondria

  • Plant cells also have mitochondria.
  • Mitochondria are the site of cellular respiration in both plants and animals.
  • Chloroplasts are the site of photosynthesis in plants.

Photosynthesis vs. Cellular Respiration

  • Photosynthesis:
    • Occurs in chloroplasts.
    • Uses radiant energy to produce carbohydrates.
  • Cellular Respiration:
    • Occurs in mitochondria.
    • Breaks down carbohydrates to produce ATP, CO2, and H2O.
    • ATP powers synthetic reactions, active transport, muscle contraction, and nerve impulse.

Comparing Living Systems

  • Photosynthesis:
    • Performed by plants.
    • Traps radiant energy from the sun, converting it into chemical energy, and storing it as glucose.
    • Occurs in chloroplasts.
    • Anabolic pathway.
  • Cellular Respiration:
    • Performed by plants and animals.
    • Breaks down chemical energy stored in glucose into ATP (usable energy).
    • Occurs in mitochondria.
    • Catabolic pathway.

Chloroplasts

  • Site of photosynthesis.
  • Bound by inner and outer membranes.
  • The stroma is the inner fluid containing proteins and chemicals for glucose synthesis.
  • Contains lamellae.

Chloroplasts - Thylakoids and Chlorophyll

  • Thylakoids are flattened sacs containing chlorophyll.
  • Chlorophyll is a green pigment that traps solar energy.
  • Thylakoids are stacked in grana, connected by lamellae.

Mitochondria

  • Site of cellular respiration.
  • Bound by inner and outer membranes.
  • The matrix is the fluid-filled space of the inner membrane containing proteins and chemicals to break down glucose into ATP.

Mitochondria - Cristae

  • The folds of the inner membrane are called cristae.
  • Cristae increase surface area for ATP production.

Anabolic vs. Catabolic Pathways

  • Anabolic pathways:
    • Synthesize larger molecules from smaller ones.
    • Require energy (endergonic).
    • Example: Photosynthesis.
  • Catabolic pathways:
    • Break down larger molecules into smaller ones.
    • Release energy (exergonic).
    • Example: Cellular respiration.