Build a DNA Molecule

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DNA TO PROTEIN

BUILD A DNA MOLECULE

Molecular machines copy DNA

Your body produces billions of new cells every day. Each time one of your cells divides, it must first copy the genetic information contained within its nucleus. Copying the genetic information in one cell using this activity would take more than 95 years*, yet molecular machines in your cells accomplish this feat in about 6 to 8 hours.

In order to speed up the copying process, DNA replication begins at multiple locations along each chromosome. The two DNA strands are pulled apart and copied in both directions at the rate of about 50 nucleotides per second.

It would take nearly 5,000 strands of DNA laid side by side to equal the width of a human hair. At the magnification shown here (about 7 million X), an average human chromosome would be roughly 621 kilometers (385 miles) long, or roughly the distance between San Francisco and Los Angeles, CA.
See the size of a nucleotide as compared to other objects

Complementary base pairing

These models are based on the molecular structure of real nucleotides. The "+" and "-" symbols on the models represent positive and negative charges that work like tiny magnets to hold complementary bases together. Complementary base-pairing ensures that DNA strands are copied accurately, with just a few errors for each round of replication. Forces between neighboring nucleotides stack the bases on top of one another and twist the DNA strands into a double-helix.

*Assuming a rate of 2 base pairs per second x the 6 billion base pairs you inherit from your parents.

Funding provided by a Howard Hughes Medical Institute Precollege Science Education Initiative for Biomedical Research Institutions Award (Grant 51006109)