Interactive molecule guide — drag the right molecules to build each reaction
Photosynthesis
Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. It takes place in the chloroplasts of plant cells, using the green pigment chlorophyll to absorb sunlight.
Plants take in carbon dioxide (CO₂) through tiny pores called stomata, and absorb water (H₂O) through their roots. Using light energy, they rearrange the atoms to produce glucose (C₆H₁₂O₆) and release oxygen (O₂).
6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
Challenge
Drag the correct molecules (in the right amounts!) into the reaction zone.
Reaction Zone
Correct! Light energy rearranges the atoms of CO₂ and H₂O into glucose and oxygen.
Products
Did you know? Photosynthesis produces the oxygen that almost all living organisms need to survive and is the starting point of nearly every food chain on Earth.
Aerobic respiration is the process by which cells break down glucose using oxygen to release energy. This happens in the mitochondria — often called the powerhouses of the cell.
The energy released is stored as ATP, which cells use to power everything from muscle movement to brain activity. The waste products are carbon dioxide and water — the exact reverse of photosynthesis!
Aerobic respiration is very efficient, producing around 38 ATP molecules per glucose.
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP)
Challenge
Drag the correct reactants for aerobic respiration into the reaction zone.
Reaction Zone
Correct! Cells break down glucose with oxygen to release energy, producing CO₂ and H₂O.
Products
Connection: Aerobic respiration is the reverse of photosynthesis. Plants produce glucose and oxygen; animals (and plants!) consume them and produce CO₂ and H₂O. A beautiful cycle in nature.
When oxygen is not available, cells can still release energy from glucose through anaerobic respiration — but much less efficiently.
In yeast and some bacteria (fermentation): glucose is broken down into ethanol (C₂H₅OH) and carbon dioxide. This is used in brewing and baking — the CO₂ makes bread rise and beer fizzy!
In animals and muscles: glucose is broken down into lactic acid (C₃H₆O₃). This causes the burning feeling in your muscles during intense exercise.
Both produce only 2 ATP per glucose — far less than the 38 from aerobic respiration.
In yeast: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + energy (2 ATP)
In animals: C₆H₁₂O₆ → 2C₃H₆O₃ + energy (2 ATP)
Challenge — Fermentation (Yeast)
Drag the correct reactant for yeast fermentation.
Reaction Zone
Correct! Without oxygen, yeast ferments glucose into ethanol and CO₂ — this is how bread and beer are made!
Products
Challenge — Lactic Acid (Animals)
Drag the correct reactant for anaerobic respiration in muscles.
Reaction Zone
Correct! During intense exercise, your muscles produce lactic acid when oxygen runs low. That is the burning feeling!
Products
Comparison: Aerobic respiration produces ~38 ATP per glucose. Anaerobic produces only 2 ATP. That is why you cannot sprint forever — your muscles switch to anaerobic respiration when oxygen runs low, which is far less efficient and builds up lactic acid.