Help Window:
The first step of replication is "unzipping" the DNA molecule. This will divide
the molecule lengthwise.
Select Unzip to divide the molecule.
Description:
Selecting the "Unzip" button causes the DNA molecule to split lengthwise.
What Happened Window:
In a real cell, the molecule unwinds from spools made of protein, then
untwists. (Here the molecule is already unwound and untwisted.) The DNA now
resembles a ladder. Enzymes, special kinds of proteins, move up the ladder,
breaking the rungs.
Drag and drop from well:
A
G
C
T
Help Window:
DNA is made up of four types of bases: adenine (A), cytosine (C), guanine (G),
and thymine (T). Each base has a complement -- another base that it can connect
to. A complements T, and C complements G.
Drag bases from the left to their complementary bases on the DNA strands. Don't
worry about the orientation of a base -- it will automatically flip, if it
needs to, as it approaches the DNA strand.
Description:
Nucleotides are dragged from one area of the screen to the separated DNA strands.
What Happened Window
Well done. Replication is complete.
Our new DNA molecules consist of only a few base pairs. Not so with real DNA.
Each human chromosome, for example, contains millions of base pairs. All 46
human chromosomes contain 3 billion pairs.
If you haven't already done so, check out Protein Synthesis.
