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Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in intermolecular reactions, whereas discussion of steric effects often focus on intramolecular interactions. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions. Steric hindrance between adjacent ...
Plants can protect themselves from abiotic stress in many different ways, and most include a physical change in the plant’s morphology. Phenotypic plasticity is a plant’s ability to alter and adapt its morphology in response to the external environments to protect themselves against stress. [ 2 ]
Van der Waals strain is strain resulting from Van der Waals repulsion when two substituents in a molecule approach each other with a distance less than the sum of their Van der Waals radii. Van der Waals strain is also called Van der Waals repulsion and is related to steric hindrance . [ 1 ]
Cytokines (/ ˈ s aɪ t ə k aɪ n /) [1] are a broad and loose category of small proteins (~5–25 kDa [2]) important in cell signaling. Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptors on the target
The plant immune system carries two interconnected tiers of receptors, one most frequently sensing molecules outside the cell and the other most frequently sensing molecules inside the cell. Both systems sense the intruder and respond by activating antimicrobial defenses in the infected cell and neighboring cells.
Symptoms will often appear overnight, affecting many types of plants. Leaves and stems may turn black, and buds and flowers may be discoloured, and frosted blooms may not produce fruit. Many annual plants, or plants grown in frost free areas, can suffer from damage when the air temperature drops below 40 degrees Fahrenheit (4 degrees Celsius).
The interaction between the two methyl groups is repulsive (van der Waals strain), and an energy barrier results. A measure of the potential energy stored in butane conformers with greater steric hindrance than the 'anti'-conformer ground state is given by these values: [28] Gauche, conformer – 3.8 kJ/mol; Eclipsed H and CH 3 – 16 kJ/mol
In immunology, systemic inflammatory response syndrome (SIRS) is an inflammatory state affecting the whole body. [1] It is the body's response to an infectious or noninfectious insult . Although the definition of SIRS refers to it as an "inflammatory" response, it actually has pro- and anti-inflammatory components.