BIO 101 Exam 2 Study Guide - Chapter 5

Photosynthesis: Process by which green plants use sunlight to synthesize foods.
Autotroph: Organisms that produce their own food from sunlight or chemical energy.
Chloroplast: Organelles in plant cells where photosynthesis occurs.
Chemiosmotic phosphorylation: Process of ATP generation through chemiosmosis during photosynthesis.
Carbon fixation: Conversion of inorganic CO₂ into organic compounds by plants.
Photorespiration: Process where oxygen is incorporated into the Calvin cycle, leading to reduced photosynthetic efficiency.

General Formula: $6CO_2 + 6H_2O + ext{light energy} <br /> ightarrow C_6H_{12}O_6 + 6O_2$
Organisms that Perform Photosynthesis: Includes plants, algae, and some bacteria (refer to Fig. 5.2).

Visible Light Spectrum: Wavelengths from approximately 380 nm to 750 nm.
Absorbed Colors: Chlorophyll a and b absorb red and blue wavelengths (refer to Table 5.1).

Key Terms:
- Chlorophyll: Green pigment in chloroplasts.
- Mesophyll: Tissue in leaves where photosynthesis occurs.
- Stomata: Pores on leaf surfaces for gas exchange.
- Thylakoids: Membrane-bound compartments inside chloroplasts.
- Grana: Stacks of thylakoids.
- Stroma: Fluid surrounding thylakoids in chloroplasts.
- Photon: Quantum of light energy.
- Photosystem: Complexes of chlorophyll and proteins involved in light reactions (refer to Figs 5.5 and 5.6).

Stages:
1. Light Reactions: Generate ATP, NADPH, and O₂ in thylakoid membranes.
2. Carbon Reactions: Occur in stroma, utilizing ATP and NADPH to fix carbon.
Reactants and Products:
- Light Reactions: Inputs - Light, H₂O; Outputs - ATP, NADPH, O₂.
- Carbon Reactions (Calvin Cycle): Inputs - ATP, NADPH, CO₂; Outputs - Sugars (C_6H_{12}O_6).

Types:
1. C3: Standard pathway, examples - wheat, rice.
2. C4: Adapted for high light, examples - corn, sugarcane.
3. CAM: Open stomata at night, examples - cacti, succulents (see Fig. 5.11).