A typical collagen is long, stiff, inelastic and triple-stranded helical structure and is made up of tropocollagen. Tropocollagen consists of 3-coiled α chains. While hydroxylysine, hydroxyproline, and glycine are the amino acid sequence of tropocollagen.

Scurvy is a disease that affects the structure of collagen. It occurs due to impaired synthesis of collagen which results due to deficiencies of prolyl and lysyl hydroxylases.

Elastin is the second major protein present in the extracellular matrix, due to its high hydrophobic nature it constitutes extensibility and elasticity to the connective tissues. It is also considered as the main component of elastic fibers found in a ligament.

A single molecule of hemoglobin binds up to four molecules of oxygen (Hb+4O₂ = Hb(O₂)₄). The sigmoidal curve shows the cooperativity in binding of oxygen and hemoglobin. This curve is a plot between the fractional saturation of hemoglobin versus the partial pressure of oxygen.

Myoglobin bind with one oxygen molecule and functions as an oxygen storage protein. Dissociation of myoglobin from oxygen is given by
MbO₂ = Mb + O₂.