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Showing 1-20 of 35 Resources
  • The Biology of Skin Color

    The Biology of Skin Color

    Short Films

    (18 min 58 sec) Penn State University anthropologist Dr. Nina Jablonski walks us through the evidence that the different shades of skin color among human populations arose as adaptations to the intensity of ultraviolet radiation in different parts of the world. Also available in Spanish.

  • Seeing Single Molecules Move

    Seeing Single Molecules Move

    Animations

    (1 min 40 sec) Single-molecule analysis using super-resolution microscopes reveals that transcription factors are not usually found bound to their binding sites on DNA.

  • DNA Sequence Technology Improves Cancer Treatment

    DNA Sequence Technology Improves Cancer Treatment

    Clips

    (2 min 6 sec) Dr. Charles Sawyers discusses how the identification of most cancer genes could transform cancer into a chronic disease.

  • The Double Helix

    The Double Helix

    Short Films

    (16 min 53 sec) The Double Helix is the story of the scientists and evidence involved in one of the most important scientific quests of the 20th century: the discovery of the structure of DNA. Also available in Spanish.

  • The Origin of Species: Lizards in an Evolutionary Tree

    The Origin of Species: Lizards in an Evolutionary Tree

    Short Films

    (17 min 45 sec) In the Caribbean islands, adaptation to several common habitats has led to a large adaptive radiation with interesting examples of convergent evolution. Also available in Spanish.

  • The Making of the Fittest: The Birth and Death of Genes

    The Making of the Fittest: The Birth and Death of Genes

    Short Films

    (13 min 10 sec) Scientists have pieced together the evolutionary history of the Antarctic icefish. The icefish makes an excellent case study for genetic evolution as both the gain and loss of genes have led to key adaptations.

  • Regulation of Eukaryotic DNA Transcription

    Regulation of Eukaryotic DNA Transcription

    Animations

    (2 min 5 sec) General transcription factors, activators, and repressors interact to regulate the transcription of eukaryotic DNA into RNA.

  • The Chemical Structure of DNA

    The Chemical Structure of DNA

    Animations

    (2 min 44 sec) DNA's chemical properties can be harnessed for a variety of biotechnology applications.

  • Polymerase chain reaction (PCR)

    Polymerase chain reaction (PCR)

    Animations

    (54 sec) PCR is a standard laboratory technique that allows amplification of specific segments of DNA based on complementarity.

  • Learning from Mice: The Science of Transgenic Technology

    Learning from Mice: The Science of Transgenic Technology

    Clips

    (11 min 8 sec) What do humans, flies, and worms have in common? More than you might think. See how transgenic organisms are engineered, and how they enable researchers to study genetic diseases.

  • Watson constructing base pair models

    Watson constructing base pair models

    Clips

    (1 min 42 sec) During the process of trying to elucidate the structure of DNA, Jim Watson made some cardboard models to try to understand how DNA nucleotides are paired. It helped him visualize how hydrogen atoms of paired nucleotides interact with each other to form a symmetrical structure that fits the double helix model.

  • Triplet code

    Triplet code

    Animations

    (1 min 8 sec) Once the structure of DNA was discovered, the next challenge was determining how the sequence of letters coded for the 20 amino acids. In theory, one or two letters can only code for 4 or 16 amino acids, respectively. A scheme using three letters, a triplet code, is the minimum necessary to encode for all the amino acids.

  • DNA transcription (advanced detail)

    DNA transcription (advanced detail)

    Animations

    (1 min 55 sec) The process of copying DNA into messenger RNA (mRNA) is called 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 initiation complex. RNA polymerase unzips a small portion of the DNA and copies one strand into an mRNA molecule. Also available in Spanish.

  • DNA transcription (basic detail)

    DNA transcription (basic detail)

    Animations

    (1 min 55 sec) The first phase of the process of reading DNA information to make proteins starts with a molecule unzipping the DNA. The molecule then copies one of the strands of DNA into a strand of RNA, a close cousin of DNA. This process is called transcription. Also available in Spanish.

  • Sickle Cell Anemia

    Sickle Cell Anemia

    Animations

    (1 min) Sickle cell anemia is a genetic disease that affects hemoglobin.

  • Shotgun sequencing

    Shotgun sequencing

    Animations

    (1 min) In shotgun sequencing many copies of the entire genome are "blown up" into millions of small fragments. Each small fragment is sequenced. Powerful computers then assemble the individual fragments into the original configuration. Repeat sequences pose a problem for this approach because their sizes can be much larger than the small fragments.

  • Sanger method of DNA sequencing

    Sanger method of DNA sequencing

    Animations

    (52 sec) Fred Sanger developed the first technique for sequencing DNA. DNA is replicated in the presence of chemically altered versions of the A, C, G, and T bases. These bases stop the replication process when they are incorporated into the growing strand of DNA, resulting in varying lengths of short DNA. These short DNA strands are ordered by size, and by reading the end letters from the shortest to the longest piece, the whole sequence of the original DNA is revealed.

  • DNA replication (advanced detail)

    DNA replication (advanced detail)

    Animations

    (2 min 20 sec) 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. Also available in Spanish.

  • DNA replication (basic detail)

    DNA replication (basic detail)

    Animations

    (1 min 7 sec) 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. Also available in Spanish.

  • DNA replication (schematic)

    DNA replication (schematic)

    Animations

    (50 sec) The structure of DNA, discovered by James Watson and Francis Crick, suggests a mechanism of replication. The double helix unwinds, and each strand acts as a template for the construction of the new DNA molecule. Also available in Spanish.

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