为原生动物取食的开口部，有的认为是细胞器的一种。一般多在身体的前方。分化不发达的（如变形虫），仅在取食时张开。
为了检查一个卵细胞的染色体是否异常，医生用激光在卵细胞外膜上切一小口，通过这个小口抽取极体及其所含的染色体。
To check an egg for chromosomal abnormalities, doctors use a laser to make a small incision in the outer membrane, which allows them to extract the polar body and the chromosomes it contains.
当作细菌培养时，生物学家通常将细胞和营养物质混合在一个大的广口瓶里，然后打旋，就像最近葡萄收获期的那些葡萄酒发烧友一样。
When growing bacterial cultures, biologists often mix cells in with nutrients in one big jar, then swirl, much like an aficionado over the latest vintage.
该型消毒剂急性经口毒性为实际无毒级，对小鼠骨髓嗜多染红细胞无致微核作用，弱蓄积性。
It was actually nontoxic by acute oral toxicity test, did not cause micronucleus formation in mouse bone marrow polychromatic erythrocytes and had weak cumulative effect.
应用推荐