Biochemistry of Respiration

ATP is formed by adding a third phosphate to ADP, requiring energy.
This energy is stored in the high-energy bond of ATP.
Metabolism produces waste materials such as urea, carbon dioxide, and water, which are eliminated through excretion.

Glycolysis:
- Involves the breakdown of glucose (6-carbon) into two pyruvate (3-carbon) molecules.
- Occurs in the cytoplasm and does not require oxygen.
- Uses 2 ATP to initiate, producing 4 ATP for a net gain of 2 ATP per glucose.
Krebs Cycle:
- Pyruvate enters the mitochondrion, releasing CO₂ and forming acetyl coenzyme A.
- Acetyl group combines with a 4-carbon compound, forming a 6-carbon compound which loses CO₂ and produces ATP in the process.
- The cycle recycles coenzyme A and involves oxidation of hydrogen atoms.
Electron Transport Chain:
- Takes place in the cristae of mitochondria and requires oxygen.
- Electrons from hydrogen atoms move through carrier molecules, releasing energy to generate ATP.
- Final reaction combines electrons and hydrogen ions with oxygen to form water.

Anaerobic Respiration:
- Occurs without oxygen, producing lactic acid in animals and small energy yields.
- Common in muscle cells during intense exercise when oxygen is limited.
Aerobic Respiration:
- Requires oxygen to convert organic compounds into usable energy.
- Produces a significant amount of ATP, with glucose and oxygen generating carbon dioxide and water.

Metabolism encompasses all chemical reactions in living cells.
Anabolic Reactions:
- Build complex molecules from simpler ones, relying on ATP for energy.
- Processes like photosynthesis and protein synthesis are examples.
Catabolic Reactions:
- Break down complex molecules into simpler components, releasing stored energy to regenerate ATP.

ATP stores energy from reactions like respiration and photosynthesis for cellular use.
Transports energy to areas of need within the cell, converting back to ADP and phosphate when energy is released.

The process of aerobic respiration can be summarized as:
- C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (Glucose + Oxygen = Carbon Dioxide + Water)

Fermentation is the anaerobic breakdown of sugars, yielding minimal ATP.
It serves as a biotechnological process, utilizing bacteria and fungi.
Advantages:
- Provides energy in low-oxygen environments.
Disadvantages:
- Produces only 2 ATPs compared to 38 in aerobic respiration and generates toxic byproducts requiring excretion.

Employed in alcohol production, baking, yogurt, and cheese making.
Essential in producing antibiotics, insulin, human growth factors, and clotting factors.

Prepare a 10% glucose solution (400 ml) and split into two flasks (200 ml each).
Add 5g of yeast to one flask for fermentation; the other acts as a control.
Use fermentation locks half-filled with water for monitoring gas production.