Biology: Photosynthesis and Excretion

Photosynthesis

• Definition: Process by which plants, algae, and some bacteria convert light energy into chemical energy
• Equation: 6CO2 + 6H2O + light energy → C6H12O6 (glucose) + 6O2
• Importance:
  • Produces oxygen for atmosphere
  • Provides energy for plant growth and development
  • Supports food chain (herbivores, carnivores, etc.)
• Factors affecting photosynthesis:
  • Light intensity
  • Temperature
  • Water availability
  • CO2 concentration

Excretion

• Definition: Process by which living organisms remove waste and excess substances from the body
• Importance:
  • Maintains homeostasis (balance of body fluids and chemicals)
  • Prevents toxicity and poisoning
  • Regulates pH and ion balance
• Types of excretion:
  • Kidneys (urine)
  • Lungs (CO2, water vapor)
  • Skin (sweat)
  • Liver (bile)

Respiration

• Definition: Process by which living organisms generate energy from the breakdown of glucose
• Equation: C6H12O6 (glucose) + 6O2 → 6CO2 + 6H2O + energy (ATP)
• Importance:
  • Provides energy for cellular activities
  • Supports growth and maintenance
  • Essential for life
• Types of respiration:
  • Aerobic (oxygen present)
  • Anaerobic (oxygen absent)

Transpiration

• Definition: Process by which water is transported through plants from roots to leaves and released as water vapor
• Importance:
  • Helps regulate plant temperature
  • Supports photosynthesis
  • Maintains turgor pressure (plant rigidity)
• Factors affecting transpiration:
  • Temperature
  • Humidity
  • Light intensity
  • Wind speed

Nutrition

• Definition: Process by which living organisms obtain and utilize nutrients for energy, growth, and maintenance
• Types of nutrition:
  • Autotrophic (self-nourishing, e.g., photosynthesis)
  • Heterotrophic (other-nourishing, e.g., consuming other organisms)
• Importance:
  • Supports growth and development
  • Maintains health and well-being
  • Essential for life

Photosynthesis

• Converts light energy into chemical energy through 6CO2 + 6H2O + light energy → C6H12O6 (glucose) + 6O2
• Produces oxygen for atmosphere and energy for plant growth and development
• Supports food chain, providing energy for herbivores, carnivores, and others
• Light intensity, temperature, water availability, and CO2 concentration affect photosynthesis

Excretion

• Removes waste and excess substances from the body to maintain homeostasis
• Prevents toxicity and poisoning by regulating pH and ion balance
• Occurs through kidneys (urine), lungs (CO2, water vapor), skin (sweat), and liver (bile)

Respiration

• Generates energy from glucose breakdown through C6H12O6 (glucose) + 6O2 → 6CO2 + 6H2O + energy (ATP)
• Provides energy for cellular activities, growth, and maintenance
• Essential for life, with aerobic (oxygen present) and anaerobic (oxygen absent) types

Transpiration

• Transports water through plants from roots to leaves and releases as water vapor
• Helps regulate plant temperature, supports photosynthesis, and maintains turgor pressure
• Affected by temperature, humidity, light intensity, and wind speed

Nutrition

• Obtains and utilizes nutrients for energy, growth, and maintenance
• Autotrophic (self-nourishing, e.g., photosynthesis) and heterotrophic (other-nourishing, e.g., consuming other organisms) types
• Supports growth, development, health, and well-being, and is essential for life