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Speaker 1: Welcome to brain Stuff from how Stuff Works dot com

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Speaker 1: where smart Happens. Hi. I'm Marshall Brain with today's question,

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Speaker 1: why do apples and potatoes turn brown when you slice them?

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Speaker 1: And how do you keep them from turning brown? All cells,

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Speaker 1: whether they're bacteria cells, human cells, or apple cells, contain

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Speaker 1: thousands of enzymes. These enzymes do all the work necessary

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Speaker 1: for the cell to live its life. Once you cut

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Speaker 1: the fruit, you open up some of the cells. One

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Speaker 1: of the enzymes inside the cell, tyrosinees, now has access

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Speaker 1: to oxygen in the air, and it does its thing,

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Speaker 1: turning the fruit brown. This is the same thing that

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Speaker 1: causes brown spots and apples when you drop them. The

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Speaker 1: easiest way to prevent the browning is to put the

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Speaker 1: sliced apples in water so that the enzyme doesn't have

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Speaker 1: access to oxygen. You can also heat the apples to

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Speaker 1: the nature the enzyme, or lemon juice also inactivates the enzyme.

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Speaker 1: In humans, tyrosine is also important because it helps create melanin,

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Speaker 1: which causes tanning. The lack of tyrosenes in humans leads

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Speaker 1: to albinism. So in humans, the browning that tyrozenes causes

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Speaker 1: is actually a good Thing. Do you have any ideas

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Speaker 1: or suggestions for this podcast? If so, please send me

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Speaker 1: an email at podcast at how stuff works dot com.

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Speaker 1: For more on this and thousands of other topics, go

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Speaker 1: to how stuff works dot com