jpepsred
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The following is taken from my book.

"During DNA replication, the whole DNA molecule unwinds and unzips, but one length at at a time, not all at once. The replication fork moves along the molecule"

How can only one strand of DNA unwind and unzip at a time? Surely they both unwind together.

Or is the phrase poorly worded, perhaps? Does it mean only one molecule of DNA is copied at a time?
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username2396569
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(Original post by jpepsred)
The following is taken from my book.

"During DNA replication, the whole DNA molecule unwinds and unzips, but one length at at a time, not all at once. The replication fork moves along the molecule"

How can only one strand of DNA unwind and unzip at a time? Surely they both unwind together.

Or is the phrase poorly worded, perhaps? Does it mean only one molecule of DNA is copied at a time?
What this means is, only small portions of the long DNA molecule are unzipped and unwound at a time during replication. So, instead of the whole DNA molecule separating into 2 strands all at once, only a small bit of the DNA molecule separates, so that at any one time only a few bases are exposed. Watch some videos on youtube or something about DNA replication, it'll become quite clear.
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jpepsred
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thanks, that really helps. Are the lengths equal to one gene then?
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username1221160
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I second checking out youtube videos. It's often far easier to understand some of the concepts in molecular biology that way than wordy descritipions.

(Original post by jpepsred)
thanks, that really helps. Are the lengths equal to one gene then?
No, not least because there is a huge variation in gene length, from a few hundred base pairs to over 100 thousand.
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