The hydrogen bonding atoms in melatonin are phospholipids and cholesterol.
<h3>What is Hydrogen bonding?</h3>
This is the type of interaction which involves a hydrogen atom being covalently bound to a more electronegative "donor".
Melatonin controls sleep-wake cycle and has phospholipids and cholesterol which have high affinity for hydrogen bonding.
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4. it remains in its initial phase
The mass per volume of a substance is called its density.
Exothermic reactions transfer energy to the surrounding, usually as heat.