Once a gene has been transcribed into messenger RNA (mRNA), it is edited in a process called splicing. Noncoding regions called introns are removed, leaving protein-coding regions called exons.
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.
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...
The ribosome is a molecular factory that translates the genetic information in RNA into a string of amino acids that becomes a protein. Inside the ribosome, the genetic code of the RNA is read three letters at a time and compared with the corresponding code on a transfer molecule. When a match...
Messenger RNA (mRNA) carries DNA's genetic information to the ribosome, where it is translated into a sequence of amino acids. mRNA is fed into the ribosome, and it is positioned so that it can be read in groups of three letters, known as codons. Each mRNA codon is matched against the transfer...
How a nerve cell gets its identity, sends axons, and makes connections with other cells.
An overview of embryonic development, the progressive differentiation of cells, and properties of embryonic stem cells.
The role of stem cells in regeneration, and ongoing research to improve mammalian regeneration potency.
Dr. Evans reviews how PPARs regulate body weight by controlling whether fat is burned or stored.
Dr. Barbara Meyer explains the value of studying model organisms and introduces the nematode C. elegans.
Having too many chromosomes can lead to too much gene expression. Dr. Meyer explains how the gene that controls dosage compensation in C. elegans works.
Four lectures highlight the research of two scientists who have made groundbreaking discoveries elucidating the molecular basis of circadian clocks—the internal timekeepers that govern fluctuations in behavior and physiology on a 24-hour cycle.
Although tiny in size, the fruit fly has had a major impact on our understanding of circadian rhythms.
Dr. Rosbash discloses how scientists have persuaded Mother Nature to reveal the inner workings of the fruit fly's biological clock.
Dr. Takahashi describes the powerful strategies that he and others have harnessed for understanding biological clocks in mammals.
After the end of the last ice age 10,000 years ago, populations of marine stickleback fish became stranded in freshwater lakes dotted throughout the Northern Hemisphere in places of natural beauty like Alaska and British Columbia. These remarkable little fish have adapted and thrive, living...
A lesson that requires students to transcribe and translate portions of the wild-type and mutant rock pocket mouse Mc1r genes and compare sequences to identify the locations and types of mutations responsible for the coat color variation described in the film.
To accompany the lecture series Evolution: Constant Change and Common Threads.
This guide correlates all the resources available on the Holiday Lectures on Science DVDs and throughout the BioInteractive.org website to specific Big Ideas, Enduring Understandings, and Essential Knowledge threads of the new AP® Biology Curriculum Framework.
The following classroom-ready resources complement Got Lactase? The Co-evolution of Genes and Culture, which tells the story of the evolution of the ability to digest lactose, a genetic trait that arose in humans within the last 10,000 years in some pastoralist cultures.
Follow human geneticist Spencer Wells, Director of the Genographic Project of the National Geographic Society, as he tracks down the genetic changes associated with the ability to digest lactose as adults, tracing the origin of the trait to less than 10,000 years ago, a time when some human...
Topics include: PCR, DNA Sequencing, Genetic Engineering, and Microarray. This guide includes multiple classroom-ready worksheets to accompany HHMI’s virtual labs.
Topics include: Gene expression, RNA structure and function, transcription, RNA processing, translation, and post-translational events.
Topics include: Gene regulation mechanisms and examples, gene regulation and human disease, and RNA interference.
The human body has at least a trillion ways of recognizing that something foreign has invaded.
A hands-on activity in which students interpret molecular diagrams and build physical models of eukaryotic gene regulation.
The developing brain needs a constant source of new cells as it builds the circuits that will control behavior.
Dr. Elinor Karlsson discusses her work with dogs as a model organism for genomic studies.
... but that's not all they'll do. Several genes determine the diverse shapes and functions of crustacean appendages.
Chromosomes change form as a cell divides to ensure that each daughter cell gets a full, intact copy of the genome.
Using super-resolution microscopes, scientists have uncovered how single protein molecules behave, and the results are astonishing.
How a cell infected by a virus signals cytotoxic T lymphocytes to kill the cell before the virus replicates and spreads.
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.
Dengue virus has sophisticated mechanisms for entering a cell, for replicating its RNA genome, and for translating proteins.
This animation shows how the protein MECP2, in conjuction with another protein complex, can act as an "on-off' switch for gene expression.
A 3D animation showing the molecule p53 binds to DNA and initiates the transcription of mRNA.
The PPAR-gamma receptor activates certain genes in a fat cell, resulting in the storage of fat and changes in hormone levels.
General transcription factors, activators, and repressors interact to regulate the transcription of eukaryotic DNA into RNA.
Watch these animations display the dynamic orchestration of the molecular events of the Drosophila biological clock.
A single transcription factor controls this operon, which contains five genes necessary to produce bioluminescence.
This animation shows the molecular interactions involved in the negative feedback loop responsible for circadian rhythms in mammals.
Quorum sensing regulates gene expression by a protein phosphorylation cascade that controls transcription.
This animation demonstrates how cancerous cells could be destroyed using a modified virus.
This "morph" animation demonstrates how the expression of a particular toolkit gene in a butterfly larva corresponds to the location of the wing eyespots in an adult butterfly.
The poster from the 2006 Holiday Lectures on Science, Potent Biology: Stem Cells, Cloning, and Regeneration, illustrates the role of stem cells during human embryonic development.
These classroom-ready resources complement the short film Evolving Switches, Evolving Bodies, which tells the story of the dramatic transformation of stickleback fish as they adapted to living in freshwater habitats drastically different from the ocean.
Understand how quorum sensing works by reasoning through experiments involving genetically-engineered bioluminescent bacteria.
Learn about how gene switches can control expression of genes in different tissues.
DNA microarrays, or gene chips, are an important new technology for genomic research. Learn how researchers use computing to analyze and interpret the huge datasets generated by microarray experiments.
Lactose tolerance, sickle cell anemia, and bitter taste perception are three examples of recently evolved human traits.