Do we adsorb the same amount of protein For the amount of protein we consume, for example if we consume 10 gram protein then it is not sure that our body will adsorb 10 gm protein, the adsorption of protein in our body depends upon bio availability of the protein  source.

Bio availability is the percentage of protein digested in our body. The protein from animal source has more bio availability then plant source. It can be measured on a scale of 0%-100%

Protein Source Bio-Availability Index
Whey Protein Isolate Blends 100-159
Whey Concentrate 104
Whole Egg 100
Cow’s Milk 91
Egg White 88
Fish 83
Beef 80
Chicken 79
Casein 77
Rice 74
Soy 59
Wheat 54
Beans 49

As we can see from above table the whey has more bio availability and therefore is used as foremost protein source as compared to plant protein