Resources by BioInteractive

Building blocks of DNA

This animation shows that Adenine (A), cytosine (C), guanine (G), and thymine (T) are the components of nucleic acid that make up DNA.

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Chargaff's ratio

This animation looks at research which led to solving the structure of DNA.  In 1950, Erwin Chargaff published a paper stating that in the DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of cytosine to guanine. This became known as Chargaff's ratio, and it was an important clue...

Coding sequences in DNA

Of the 3 billion letters in the human genome, only 1% directly code for proteins. Of the rest, about 25% make up genes and their regulatory elements. The functions of the remaining letters are still unclear.

Cytoplasmic factors

This animation shows how cytoplasmic factors play a significant part in determining how a cell develops. This segment discusses their importance in turning the appropriate genes on and off for proper development.

Damage to DNA leads to mutation

Reactive molecules, such as free radicals, and solar ultraviolet radiation can lead to mutations in DNA. Most mutations are corrected, but in rare cases mutations can accumulate and cause diseases such as cancer.

DNA packaging

This animation describes how DNA is tightly packed in the nucleus of every cell. DNA wraps around special proteins called histones, which form loops of DNA called nucleosomes. These nucleosomes coil and stack together to form fibers called chromatin. Chromatin in turn forms larger loops and coils to form...

DNA replication (advanced detail)

This animation shows how both strands of the DNA double helix act as templates for the new DNA strands. Incoming DNA is unraveled by the enzyme helicase, resulting in the 3' strand and the 5' strand. The 3' strands and the 5' strands are replicated by a DNA polymerase enzyme but in different ways.

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DNA replication (basic detail)

Using information from molecular research, this 3-D animation shows how DNA is replicated at the molecular level. It involves an enzyme that unwinds the DNA, and other enzymes that copy the two resulting strands.

This resource is part of the ...

DNA replication (schematic)

An animation showing that the structure of DNA, discovered by James Watson and Francis Crick, suggests a mechanism of DNA replication. The double helix unwinds, and each strand acts as a template for the construction of the new DNA molecule.

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DNA transcription (advanced detail)

This animation shows the process of copying DNA into messenger RNA (mRNA), transcription. Transcription factors assemble at the promoter region of a gene, bringing an RNA polymerase enzyme to form the transcription initiation complex. Activator proteins at the enhancer region of DNA then activate the transcription...