Changes

== Protein ==

== Protein ==

* Can be divided into two groups.

* Can be divided into two groups, caseins and whey.

** '''Caseins''': precipitate at pH 4.5 or lower. They comprise 40-80% of total milk protein and exist in colloidal suspension complexed to calcium, phosphate and magnesium.  This allows the mineral concentration in milk to exceed that of plasma.  They have little secondary structure, so are easily digestable by Rennin.  They have a high content of nutritionally essential amino acids.

Proteins are synthesised on the rough endoplasmic reticulem and migrate to the golgi, where they are processed and complexed with minerals.  Golgi vesicles containing the proteins pinch off and migrate towards the plasma membrane where their contents is released by exocytosis.

** '''Whey''': remain in solution at pH 4.5 or lower.  They comprise 20-60% of the total milk protein.  They are rich in α lactalbumin which is required for the synthesis of the milk carbohydrate lactose.  In ruminants, β lactoglobulin is also a majoy whey protein component, supplying the neonate with amino acids.

*** Proteins are synthesised on the rough endoplasmic reticulem and migrate to the golgi, where they are processed and complexed with minerals.  Golgi vesicles containing the proteins pinch off and migrate towards the plasma membrane where their contents is released by exocytosis.  

== Carbohydrate:Lactose ==

== Carbohydrate:Lactose ==