Chain Extension Method
Chain Extension Method - Related Videos
10:26
Rewiring Neuronal Circuits: A New Method for Fast Neurite Extension and Functional Neuronal Connection
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Cited by 8 •
2017
This procedure describes how to rapidly initiate, extend and connect neurites organized in microfluidic chambers using poly-D-lysine-coated beads fixed to micropipettes that guide neurite elongation.
28:40
Proboscis Extension Response (PER) Assay in Drosophila
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Cited by 120 •
2007
Proboscis extension response or PER is a taste behavior assay that has been used in flies as well as in honeybees. When the proboscis makes contact with an attractive substance, the fly extends its proboscis to consume the substance. Solutions of various sugars are very attractive to the fly.
13:27
PCR: The Polymerase Chain Reaction
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2023
The polymerase chain reaction, or PCR, is a technique used to amplify DNA through thermocycling – cyles of temperature changes at fixed time intervals. Using a thermostable DNA polymerase, PCR can create numerous copies of DNA from DNA building blocks called dNTPs. There are three steps in PCR: denaturation, annealing, and elongation. Denaturation is the first step in the cycle and causes the DNA to melt by disrupting hydrogen bonds between the bases resulting in single-stranded DNA. Annealing...
01:28
Electron Transport Chains
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2019
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle. The ETC is comprised of...
03:32
Using a Macrophage Conditioned Medium to Promote Neuron Extensions
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2025
This video demonstrates an assay for promoting the growth of neuron projections known as neurite outgrowth using the macrophage-conditioned medium. Co-culture neurons and macrophages with cAMP and harvest the macrophage-derived conditioned medium. Growing the neurons with the conditioned medium promotes neurite outgrowths. These outgrowths are fluorescently labeled and visualized using a fluorescence microscope.
FAQs
A reactive functional group provides the site where a new covalent bond can form with an organometallic reagent or coupling partner. Its reactivity determines whether the starting structure can connect successfully to the added fragment. After bond formation, functional-group conversion may be necessary to preserve the required reactivity or create the chemical functionality needed in the next synthetic step.
The identity of the reagent or coupling partner largely determines how many atoms are introduced and where the new bond forms. Reagent compatibility and reaction conditions also influence whether the intended connection is maintained. These factors allow chemists to control both the size of the molecular framework and the placement of functional groups in the product.
Bond formation does not always leave the molecule with the functionality required for subsequent synthesis. Converting a functional group can preserve its useful reactivity, change it into a different reactive form, or prepare the product for another construction step. This makes chain extension part of a planned sequence rather than an isolated operation.
A chemist first selects an existing molecular structure with a suitable reactive functional group, then chooses an organometallic reagent or coupling partner capable of forming the desired bond. The reaction conditions must support reagent compatibility. After extension, the product is evaluated for the intended framework and may undergo functional-group conversion before further synthesis.
Reagent compatibility determines whether the selected reactants can interact without disrupting important parts of the starting structure or the newly forming product. Reaction conditions further influence bond formation and the retention of desired functional groups. Careful control therefore helps produce the intended chain length, connectivity, and reactivity instead of an unsuitable molecular framework.
This strategy is useful when a synthesis requires a homologous series, a more complex natural product, a pharmaceutical structure, or an advanced material. It provides a way to build on an existing molecular framework while controlling the added atoms and functional groups. In chemistry, that makes it relevant to both target-molecule preparation and materials-oriented synthesis.