00:02
This question asks, how many bar bodies would you expect to see in a human cell containing the following chromosomes? so for a, we are going to expect one bar body.
00:14
And just to go over what bar bodies are before we continue on, bar bodies are going to be inactivated x chromosomes.
00:32
Right? because in females, we see an inactivation of the x chromosome because females have two.
00:38
Well, one is going to be inactivated.
00:41
And it becomes this bar body, which is an aggregate form of the chromosome in its inactivated state.
00:49
So depending on how many x chromosomes you have, you will see differing numbers of barbodies.
00:58
So for a, there's two x chromosomes.
01:00
We should have one as our total.
01:03
So one is going to remain.
01:05
The other one is going to be inactivated.
01:06
For b, we have xy, so there will be 0 bar bodies since we only have the 1x chromosome.
01:15
Same thing goes for c, right? because we have an x and an o, the o is just a placeholder, so we only have the 1x chromosome.
01:22
We can't inactivate that because that means we would have 0 x chromosomes.
01:26
So in this case we have 0 inactivated x chromosomes, therefore 0 bar bodies...