Which of the following occurs during S phase? (A) condensation of the chromosomes (B) replication of the DNA (C) separation of sister chromatids (D) spindle formation

Video transcript

Welcome back. Here's our next question. During which phase is the central zone. A cytoplasmic protein replicated. So probably when I look at this question I first want to recall from the content videos, what the central zone is and that's that organ al near the nucleus. That is the organizer of the micro tubules in the cell. It's replicated and then it moves to the poles of the cell where we have spindle formation from it and helps to pull apart the sister chroma tits during mitosis. So very important, it's kind of directing the action there as the cells split, making sure the D. N. A. Goes where it's supposed to. So now we need to think about which phase of the cell cycle that replication happens. And we look at our answer choices. We have G one phase choice B G zero phase C. S. Phase or D. G. Two phase. So again, let's recall from our sample video from our content video. I'm sorry what our cell cycle is and I'm just going to put up a little kind of basic diagram here just to help us remember. And I've shaded out mitosis because we can see this does not take place during mitosis. That's not one of our choices. So We have here we've got G and as we can remember from the G. That's a growth phase immediately after mitosis. Organelles being produced cells getting bigger and off to the side here we have our G phase which is sort of a resting phase. Not dividing the cells. Just doing what it does, doing its its function in the liver or the kidney or wherever it is. Um It can might stay in that phase its whole existence or it might be tipped back into the replication phase due to various cell signals. Then we've got the S. Phase that's our synthesis face And then G. two immediately before mitosis is another growth face. And it's also preparation for cell division. So as we look at these phases, the synthesis phase is where we have D. N. A replication, DNA synthesis, preparing two sets of chromosomes for that mitosis and along with DNA replication. This is also where we have the Center zone replication. So maybe you can help to recall two different replications happening in that S. Phase. So our correct answer then is choice see the S. Phase for the phase when the center zone is replicated. See you in the next video.