Master Formula: Algae Identification

CLASS         | CHLOROPHYLLS  | ACCESSORY        | STORAGE           | CELL WALL
Chlorophyceae | Chl a + CHL B | (none specific)  | STARCH            | Cellulose
Phaeophyceae  | Chl a + CHL C | FUCOXANTHIN       | LAMINARIN         | Cellulose + ALGIN
Rhodophyceae  | Chl a + CHL D | PHYCOERYTHRIN     | FLORIDEAN STARCH  | Cellulose

Memory Formula: "b-c-d Rule"

• Green (Chloro) → b (same as higher plants — continuity of green plants)
• Brown (Phaeo) → c (middle letter)
• Red (Rhodo) → d (last letter, deepest in ocean)

Commercial Products Formula

RED ALGAE   → AGAR (Gelidium, Gracilaria) — used in microbiological culture media
BROWN ALGAE → ALGIN (Laminaria, Sargassum) — used as thickener in food/pharma
RED ALGAE   → CARRAGEENAN (Chondrus) — used in dairy products

Habitat Depth Formula

Green algae  → Shallow water (chlorophyll absorbs red light, absorbed near surface)
Brown algae  → Intertidal / Cold coastal (moderate depth)
Red algae    → Deep marine (phycoerythrin absorbs blue-green light that penetrates deepest)

Critical NEET Formula: NEVER confuse

• Agar ≠ Brown algae (TRAP!)
• Agar = Red algae (Gelidium, Gracilaria)
• Algin = Brown algae (Laminaria, Sargassum)