当皮肤暴露在阳光下， 紫外线辐射会引发游离原子团的形成，转而破坏皮肤细胞中的DNA， 引起肿瘤的生长。
When the skin is exposed to sunlight, the radiation triggers the formation of free radicals which, in turn, damages the DNA in skin cells, causing tumours to grow.
当胚发育到4—6个细胞时，在胚囊珠孔瑞的游离核之间先形成细胞壁。细胞壁的形成是以自由壁的方式从珠孔端到合点端自外向内进行。
The free cell wall formation occurs first in the micropylar end when the embryo is 4-6 celled stage, then to the chalazal end and the center.
细胞游离面部分微绒毛的微丝形成中心根并深入胞质。
The microfilaments of some microvilli formed core rootlets and entered into the cytoplasm.
应用推荐