Скачать или смотреть Lecture No 8 RESPIRATRY PIGMENT

Respiratory Pigments
Respiratory pigments are specialized proteins that transport oxygen (O₂) — and in some cases carbon dioxide (CO₂) — within the blood or body fluids of animals. They greatly increase the oxygen-carrying capacity of blood compared to oxygen dissolved in plasma alone.
Main Functions
Bind oxygen at respiratory surfaces (lungs, gills, skin)
Transport oxygen to tissues
Release oxygen where it is needed for cellular respiration
Some also help in carbon dioxide transport
Types of Respiratory Pigments
1. Hemoglobin
Found in: Most vertebrates (including humans) and some invertebrates
Location: Inside red blood cells
Color: Red when oxygenated
Metal present: Iron (Fe²⁺)
Example: Present in humans and other mammals
Hemoglobin consists of four subunits, each capable of binding one oxygen molecule. It forms oxyhemoglobin when combined with oxygen.
2. Hemocyanin
Found in: Arthropods and mollusks
Location: Dissolved directly in blood (hemolymph)
Color: Blue when oxygenated
Metal present: Copper (Cu²⁺)
Unlike hemoglobin, hemocyanin is not contained in cells.
3. Myoglobin
Found in: Muscle cells of vertebrates
Function: Stores oxygen in muscles
Metal present: Iron
Myoglobin has a higher affinity for oxygen than hemoglobin and helps supply oxygen during intense muscular activity.