 It has been estimated that average @-@ sized bacteria contain about 2 million proteins per cell ( e.g. E. coli and Staphylococcus aureus ) . Smaller bacteria , such as Mycoplasma or spirochetes contain fewer molecules , namely on the order of 50 @,@ 000 to 1 million . By contrast , eukaryotic cells are larger and thus contain much more protein . For instance , yeast cells were estimated to contain about 50 million proteins and human cells on the order of 1 to 3 billion . Note that bacterial genomes encode about 10 times fewer proteins than humans ( e.g. small bacteria ~ 1 @,@ 000 , E. coli : ~ 4 @,@ 000 , yeast : ~ 6 @,@ 000 , human : ~ 20 @,@ 000 ) . 
 It <a href='been_done' title='1'><mark>has</mark></a> been estimated that average @-@ sized bacteria contain about 2 million proteins per cell ( e.g. E. coli and Staphylococcus aureus ) . Smaller bacteria , such as Mycoplasma or spirochetes contain fewer molecules , namely on the order of 50 @,@ 000 to 1 million . By contrast , eukaryotic cells <a href='drop_aux' title='2'><mark>are</mark></a>larger and thus contain much more protein . For instance , yeast cells <a href='uninflect' title='3'><mark>were</mark></a> estimated to contain about 50 million proteins and human cells on the order of 1 to 3 billion . Note that bacterial genomes encode about 10 times fewer proteins than humans ( e.g. small bacteria ~ 1 @,@ 000 , E. coli : ~ 4 @,@ 000 , yeast : ~ 6 @,@ 000 , human : ~ 20 @,@ 000 ) . 
It done been estimated dat average @-@ sized bacteria contain bou 2 million proteins per cell ( e.g. E. coli and Staphylococcus aureus ) . Smaller bacteria , such as Mycoplasma or spirochetes contain fewer molecules , namely on the order of 50 @,@ 000 to 1 million . By contrast , eukaryotic cells larger and thus contain much more protein . For instance , yeast cells was estimated to contain about 50 million proteins and human cells on da order of 1 to 3 billion . Note tdatbacterial genomes encode abbout0 times fewer proteins den humans ( e.g. small bacteria ~ 1 @,@ 000 , E. coli : ~ 4 @,@ 000 , yeast : ~ 6 @,@ 000 , human : ~ 20 @,@ 000 ) .