Photosynthesis Process and Importance

Study Notes

Definition: Process by which plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of organic compounds (glucose)
Equation: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2
Importance:
- Produces oxygen for the atmosphere
- Provides energy for the food chain
- Supports life on Earth
Light-dependent reactions:
- Occur in the thylakoid membranes of the chloroplast
- Light energy excites electrons, which are then used to generate ATP and NADPH
Light-independent reactions (Calvin cycle):
- Occur in the stroma of the chloroplast
- ATP and NADPH from light-dependent reactions are used to convert CO2 into glucose
- Regenerate RuBP (ribulose-1,5-bisphosphate) to continue the cycle

Definition: Process by which cells generate energy from the breakdown of glucose and other organic molecules
Types:
- Aerobic respiration: Occurs in the presence of oxygen, producing ATP, water, and carbon dioxide
- Anaerobic respiration: Occurs in the absence of oxygen, producing ATP, lactic acid or ethanol, and carbon dioxide
Stages:
1. Glycolysis: Breakdown of glucose into pyruvate, producing ATP and NADH
2. Pyruvate oxidation: Conversion of pyruvate into acetyl-CoA, producing NADH and FADH2
3. Citric acid cycle (Krebs cycle): Breakdown of acetyl-CoA into carbon dioxide, producing ATP, NADH, and FADH2
4. Electron transport chain: Transfer of electrons from high-energy molecules to oxygen, generating ATP
5. Oxidative phosphorylation: Production of ATP using energy from the electron transport chain
Importance:
- Provides energy for cellular activities
- Supports life processes, such as growth, maintenance, and reproduction

Plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of glucose
Requires 6 CO2, 6 H2O, and light energy to produce glucose (C6H12O6) and 6 O2
Produces oxygen for the atmosphere, supporting life on Earth
Provides energy for the food chain through glucose production

Occur in thylakoid membranes of chloroplasts
Light energy excites electrons, generating ATP and NADPH
ATP and NADPH are used in light-independent reactions to convert CO2 into glucose

Occur in stroma of chloroplasts
ATP and NADPH from light-dependent reactions are used to convert CO2 into glucose
Regenerates RuBP to continue the cycle

Occurs in absence of oxygen, producing ATP, lactic acid or ethanol, and carbon dioxide
Supports cellular activities, growth, maintenance, and reproduction

Glycolysis: Breakdown of glucose into pyruvate, producing ATP and NADH
Pyruvate oxidation: Conversion of pyruvate into acetyl-CoA, producing NADH and FADH2
Citric acid cycle (Krebs cycle): Breakdown of acetyl-CoA into carbon dioxide, producing ATP, NADH, and FADH2
Electron transport chain: Transfer of electrons from high-energy molecules to oxygen, generating ATP
Oxidative phosphorylation: Production of ATP using energy from the electron transport chain