Related Experiment Video

Updated: Feb 1, 2026

Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples
06:04

Source and Route of Pyrrolizidine Alkaloid Contamination in Tea Samples

Published on: September 28, 2022

2.5K

Acetylcholinesterase Inhibitory Activity of Alkaloids Isolated from Stephania venosa

Sumet Kongkiatpaiboon, Nongnaphat Duangdee, Saisuree Prateeptongkum

    Natural Product Communications
    |December 4, 2018
    PubMed

    More Related Videos

    Author Spotlight: Discovering New Alkaloids in Plants with Advanced Mass Spectrometry Techniques09:36

    Author Spotlight: Discovering New Alkaloids in Plants with Advanced Mass Spectrometry Techniques

    Published on: March 8, 2024

    1.5K
    Mapping Inhibitory Neuronal Circuits by Laser Scanning Photostimulation09:50

    Mapping Inhibitory Neuronal Circuits by Laser Scanning Photostimulation

    Published on: October 6, 2011

    17.8K

    Related Concept Videos

    Excitatory and Inhibitory Effects of Neurotransmitters01:29

    Excitatory and Inhibitory Effects of Neurotransmitters

    When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of...
    12.9K
    Co-activators and Co-repressors02:04

    Co-activators and Co-repressors

    Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
    8.6K
    tRNA Activation02:26

    tRNA Activation

    Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
    22.9K
    Activation Energy01:26

    Activation Energy

    Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the rate of the reaction. However, adding heat to the reaction will increase the rate, since it causes molecules to move faster and increase the likelihood that molecules will collide. The collision and breaking of bonds represents the uphill phase of a reaction and generates the transition state. The transition state is an unstable high-energy state...
    86.6K
    Eukaryotic Transcription Activators02:42

    Eukaryotic Transcription Activators

    Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
    The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
    12.8K
    Secondary Active Transport01:55

    Secondary Active Transport

    One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
    137.8K