The head of the sperm carries special enzymes to dissolve this membrane , which it must do in order to fertilise the egg .
精子头部携带某种特殊的溶解酶,消融防护细胞棕色的外膜,唯有如此,受精方可成功。
Even if hedid fertilise the egg of a non-paired female it would not survive as ittakes two adults to raise a single chick .
即使雄鸟让单身的雌鸟产下了受精卵,但如果没有两只成年鸟的照顾雏鸟将无法生存。
The ' artificial sperm ' were then used to fertilise eggs , leading to the birth of 60 ' grossly healthy ' baby mice , who went on to have families of their own , the journal cell reports .