Imagine a city with busy streets, traffic lights, and pathways - that's like the metabolism in our bodies!

• Metabolism = All the chemical reactions happening in our bodies to keep us alive.
• 📍 Location: Mostly inside cells, but some occur outside, like digestion in our intestines.
• 🤔 Think of metabolism like different routes in a city map. There are:
  • Linear routes: Where one molecule is transformed into another, step-by-step.
  • Circular routes: Like roundabouts or cycles in the city. An example given was "Figure 4" (but we don't have the figure here).

🍀 Fun Fact: The Kyoto Encyclopedia of Genes and Genomes is like the Google Maps of metabolism!

Enzymes are like the city workers who speed up the construction of a building.

• Enzymes: Proteins that speed up chemical reactions.
• Special Power: Each enzyme is picky; it only works on specific reactions.
• Difference from non-biological catalysts: Just like platinum jewelry is versatile and matches with many outfits, non-biological catalysts like platinum can work with many reactions. But enzymes are selective!

🌟 Real-world example: Imagine you have a special key (enzyme) that can only unlock a particular door (reaction). Other keys (non-biological catalysts) are master keys, unlocking many doors!