0:00:00.270,0:00:04.870 The answer to this question is 25, unique chromosomes 0:00:04.870,0:00:07.410 in the total cellular genome. What I wanted you to 0:00:07.410,0:00:11.940 do was look at our nuclear mitochondrial chromosomes, take the 0:00:11.940,0:00:15.110 first pair, we don't want the extra copy, right, there 0:00:15.110,0:00:17.430 are two copies in this pair. We just going to 0:00:17.430,0:00:20.470 count that one as a unique chromosome. It's unique. It's 0:00:20.470,0:00:23.090 different from all the other chromosomes. And the same thing 0:00:23.090,0:00:25.320 for the second pair. We're not going to count the copy, 0:00:25.320,0:00:31.750 this is two. Third, three. Four, all the way till we get to 20, 21, 22. 0:00:31.750,0:00:34.960 And our last pair, the 23rd pair, though. 0:00:34.960,0:00:37.810 We're going to count each chromosome by itself, because 0:00:37.810,0:00:39.490 they're not the same. The X and Y 0:00:39.490,0:00:43.200 are different. So, chromosome, there's a 23rd unique one 0:00:43.200,0:00:46.140 and a 24th unique one. And then, if 0:00:46.140,0:00:52.200 we include the mitochondrial chromosome, that's 25 unique chromosomes. 0:00:52.200,0:00:54.610 Remember, you have one extra copy of every 0:00:54.610,0:00:57.180 other autosome in your genome at any given 0:00:57.180,0:00:58.880 time in the cell and there are many 0:00:58.880,0:01:02.450 mitochonria and thus many mitochondrial chromosomes in a 0:01:02.450,0:01:04.629 cell at any given moment. But when we 0:01:04.629,0:01:07.870 talk about the total cellular genome, how many 0:01:07.870,0:01:10.980 unique chromosomes there are There are a total 0:01:10.980,0:01:13.520 of 25 when we leave out the extra copies.