Why don't bacteria need a distinct nucleus and that's necessary in a human cell?

为什么细菌不需要单独的细胞核,而对人类细胞则为必需

耶鲁公开课 - 生物医学工程探索课程节选

One of the most obvious things about a red blood cell is it doesn't have nucleus, it has no nucleus.

红细胞最为明显的不同就是,它是无核的,它没有细胞核

耶鲁公开课 - 生物医学工程探索课程节选

How far you are away from the nucleus in terms of a radius, they don't depend at all on those two angles, theta they're independent of theta phi and they're independent of phi.

只和离核子的距离，也就是半径有关，它们和,另外两个角度无关，它们不决定于,也不决定于。

麻省理工公开课 - 化学原理课程节选

That most certainly isn't the Cubs, who are looking to build on their solid young nucleus of shortstop Starlin Castro, first baseman Anthony Rizzo and Gold Glove second baseman Darwin Barney.

WSJ: MLB 2013: Challengers gear up to take down Giants