Genetic Circuits
Genetic Circuits - Related Videos
09:27
RC/RL/LC Circuits
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2023
Source: Yong P. Chen, PhD, Department of Physics & Astronomy, College of Science, Purdue University, West Lafayette, IN Capacitors (C), inductors (L), and resistors (R) are each an important circuit element with distinct behaviors. A resistor dissipates energy and obeys Ohm's law, with its voltage proportional to its current. A capacitor stores electrical energy, with its current proportional to the rate of change of its voltage, while an inductor stores magnetic energy, with its voltage...
01:17
Second-Order Circuits
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2024
Integrating two fundamental energy storage elements in electrical circuits results in second-order circuits, encompassing RLC circuits and circuits with dual capacitors or inductors (RC and RL circuits). Second-order circuits are identified by second-order differential equations that link input and output signals. Input signals typically originate from voltage or current sources, with the output often representing voltage across the capacitor and/or current through the inductor. For example, in...
03:01
Drosophila Optogenetics: A Method to Manipulate Neuronal Circuits
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2023
Optogenetics enables the use of light to manipulate neurons that are genetically engineered to express specific opsins–light-sensitive proteins whose light activation triggers a change in the state of the neuron. Here we describe an optogenetic approach in Drosophila using the opsin Channelrhodopsin2. The example protocol features an optogenetics assay set to study the neuronal circuitry behind the fly's escape behavior.
01:15
First-Order Circuits
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2024
First-order electrical circuits, which comprise resistors and a single energy storage element - either a capacitor or an inductor, are fundamental to many electronic systems. These circuits are governed by a first-order differential equation that describes the relationship between input and output signals. One common example of a first-order circuit is the RC (resistor-capacitor) circuit. These circuits are used in relaxation oscillators such as neon lamp oscillator circuits. When voltage is...
01:19
The Y-to-Y Circuit
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2024
In a balanced four-wire wye-to-wye system, the arrangement involves wye-connected sinusoidal voltage sources and loads, connected through a neutral wire that links the neutral nodes of the source and load. The load impedance is connected across each phase of the load. The wye-connected source can be connected to the wye-connected load in four-wire and three-wire arrangements. A three-phase system is considered balanced when the load on each phase is equal, leading to uniform current flow and...
FAQs
Promoters provide control regions where transcription begins, while transcription factors interact with regulatory sequences to increase or decrease gene expression. Their coordinated activity links an incoming chemical or environmental signal to a selected genetic output. By arranging these elements as interacting modules, engineers can control when genes respond and how strongly the circuit changes cellular behavior.
Feedback loops connect a circuit’s output back to its regulatory elements, allowing gene expression to influence subsequent circuit activity. Depending on how the interactions are arranged, feedback can support stable switching behavior or repeated oscillations. This makes feedback especially important when a bioengineered cell must maintain a state, transition between states, or generate a timed response.
Logic functions arise when multiple regulatory interactions combine inputs according to defined activation or repression relationships. A circuit can therefore respond differently to individual signals than to their combination, producing a specific genetic output only under selected conditions. In bioengineering, this provides a way to make cellular responses conditional rather than continuously active.
The outcome depends on how promoters, transcription factors, regulatory sequences, and feedback relationships are arranged. An input may activate expression, repress it, or alter its level through these interactions. The resulting design determines which signal is recognized, which gene expression pattern follows, and whether the response behaves like a switch, oscillator, or adjustable program.
Design begins by identifying the biological input to be detected and the genetic output required in response. Engineers then combine suitable promoters, transcription factors, regulatory sequences, and, when needed, feedback loops to connect those functions. The assembled network is intended to produce a predictable response, such as sensing a signal, changing metabolism, or directing cell behavior.
These circuits are useful when cells must connect a defined biological signal to a programmed action. In metabolic engineering, they can regulate gene expression associated with cellular production processes. In disease diagnostics, they can support biosensing programs, while therapeutic design can use conditional genetic responses. Across these settings, the central goal is programmable behavior in living cells.
By combining regulatory elements into defined networks, researchers can examine how interactions among genes and regulatory factors shape cellular function. Logic functions, switches, oscillations, and biosensing programs provide distinct circuit behaviors for analyzing information processing in cells. This approach connects molecular regulation with observable outcomes and offers a framework for investigating engineered and naturally occurring control relationships.