Food and Respiration

Energy Sources and Food

• All energy in food originates from the sun.
  • Types of Energy:
  • Heat
  • Light
  • Energy producers include plants, while consumers consist of animals.
  • Decomposers: Fungi, bacteria, worms.

Food Chain Dynamics

• Plants form the base of animal food chains:
  • Example: Owl (consumer) → Flower (producer) → Caterpillar → Frog → Snake (all consumers).

Photosynthesis Overview

• Definition: Photosynthesis is the process by which producers (plants, green algae, photosynthetic bacteria) convert light energy into chemical energy.
• Key Players:
  • Green algae (Eukaryotes)
  • Photosynthetic bacteria (e.g., Prochlorococcus marinus)
• Significance of Oceans: 50% of oxygen we breathe is produced by oceanic photosynthesis.

Flow of Energy in Cells

• Energy transformation process:
  1. Light energy transformed in chloroplasts.
  2. Energy stored in glucose by mitochondria.
  3. Transformation of glucose energy into ATP.

Caloric Content and Energy Storage

• Not all calories from plants are converted directly into glucose.
  • Organisms can convert glucose into various biological macromolecules:
  • Fats
  • Phospholipids
  • Amino acids
  • Nucleotides
• These transformations store energy in covalent bonds.

Hypothetical Experiment on Diet and Strength

• Group 1: 100 people eat hamburgers made from wild lion hearts.
• Group 2: 100 people eat hamburgers made from cow hearts.
• Both groups have identical protein, fat, and calorie intake. Testing will assess if there is a significant difference in strength after one month.

Carbon Fate in Food Consumption

• Carbon from food is utilized in two primary ways:
  1. ATP Production: Carbon is lost as CO₂.
  2. Building Biomolecules: Carbon is converted into proteins, fats, etc., incorporating into body tissues.

Absorption of Biological Macromolecules

• Biological macromolecules in food get absorbed as monomers:
  • Polysaccharides → Monosaccharides
  • Fats → Fatty acids + Glycerol
  • Phospholipids → Fatty acids + Glycerol + Polar group
  • Proteins → Amino acids
  • DNA/RNA → Nucleotides
• This absorption primarily occurs in the small intestine.

Anabolism vs. Catabolism

• Anabolic Processes:

  • Build small molecules into large ones.
  • Require energy.

• Catabolic Processes:

  • Break down large molecules into small ones.
  • Release energy.

Energy Transformation in Biology

• Energy is transformed rather than created:
  • Forms of energy:
  • Chemical energy
  • Light energy
  • Kinetic energy

Understanding Potential and Kinetic Energy

• Potential Energy: Stored energy (like chemical energy).
• Kinetic Energy: Energy of movement.

Cellular Respiration Process

Glycolysis

• Input: 2 ATP; Output: 4 ATP.
• Net gain of ATP: 2.
• Location of reaction: Cytoplasm.

Citric Acid Cycle

• Produces 2 more ATP.
• Key enzyme: Pyruvate Dehydrogenase (found inside mitochondria).

Electron Transport Chain

• Location: Mitochondria.
  • Generates 36 ATP from one glucose molecule.
  • Involves the following components:
  • Intermembrane space
  • Matrix
  • Electron carriers (e.g., NADH, FADH₂)
  • Water production and ATP synthase activity.