Photosynthesis and Cellular Respiration Lecture Notes

Introduction

Objective: Compare and contrast photosynthesis and cellular respiration; explain their complementary roles in ecosystems.
Key Concepts:
- Chemical reactions involve transforming substances into new ones.
- Reactants transform into products.

Definition: Process converting sunlight into chemical energy.
Components:
- Chlorophyll: Substance in leaves that absorbs light.
- Chemical Energy: Stored in glucose (C6H12O6).
Reaction:
- 6H2O + 6CO2 + light energy → C6H12O6 + 6O2
Occurs in: Plants, algae, some bacteria.
Requirements: Light, chloroplasts.

Definition: Process releasing energy (ATP) from glucose.
Importance: Provides energy for growth, repair, and reproduction.
Components:
- Glucose: Consumed by eating plants or animals.
- Oxygen: Required for breaking down glucose.
Reaction:
- C6H12O6 + O2 → H2O + CO2 + energy (ATP)
Occurs in: All living organisms.
Requirements: Mitochondria, does not need light.

Interdependency:
- Photosynthesis and respiration are complementary; products of one are reactants for the other.
- They cycle carbon and oxygen through ecosystems.
Energy Conversion:
- Photosynthesis stores energy from the sun in glucose.
- Respiration converts glucose into usable energy (ATP).

Food Production:
- Photosynthesis makes food; respiration breaks it down.
Energy:
- Photosynthesis stores energy; respiration releases it.
Gas Exchange:
- Photosynthesis takes in CO2, releases O2.
- Respiration takes in O2, releases CO2.
Occurrence:
- Photosynthesis: plants, algae, some bacteria.
- Respiration: all living organisms.
Light Requirement:
- Photosynthesis requires light.
- Respiration does not.
Organelles:
- Photosynthesis: chloroplasts.
- Respiration: mitochondria and cytoplasm.

Relation to Ecosystems:
- Support carbon and oxygen cycling.
- Essential in maintaining balance within ecosystems.
Food Webs:
- Energy flows from plants to other organisms.
- Ultimately all energy originates from sunlight captured by plants.