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