WEBVTT

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The answer to this question is 25, unique chromosomes

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in the total cellular genome. What I wanted you to

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do was look at our nuclear mitochondrial chromosomes, take the

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first pair, we don't want the extra copy, right, there

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are two copies in this pair. We just going to

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count that one as a unique chromosome. It's unique. It's

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different from all the other chromosomes. And the same thing

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for the second pair. We're not going to count the copy,

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this is two. Third, three. Four, all the way till we get to 20, 21, 22.

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And our last pair, the 23rd pair, though.

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We're going to count each chromosome by itself, because

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they're not the same. The X and Y

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are different. So, chromosome, there's a 23rd unique one

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and a 24th unique one. And then, if

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we include the mitochondrial chromosome, that's 25 unique chromosomes.

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Remember, you have one extra copy of every

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other autosome in your genome at any given

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time in the cell and there are many

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mitochonria and thus many mitochondrial chromosomes in a

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cell at any given moment. But when we

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talk about the total cellular genome, how many

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unique chromosomes there are There are a total

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of 25 when we leave out the extra copies.