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In chemistry, many reactions depend on the absorption of photons to provide the energy needed to overcome the activation energy barrier and hence can be labelled light-dependent. Such reactions range from the silver halide reactions used in photographic film to the creation and destruction of ozone in the upper atmosphere.
Plant perception is the ability of plants to sense and respond to the environment by adjusting their morphology and physiology. [1] Botanical research has revealed that plants are capable of reacting to a broad range of stimuli, including chemicals, gravity, light, moisture, infections, temperature, oxygen and carbon dioxide concentrations, parasite infestation, disease, physical disruption ...
Phototropism in plants such as Arabidopsis thaliana is directed by blue light receptors called phototropins. [13] Other photosensitive receptors in plants include phytochromes that sense red light [14] and cryptochromes that sense blue light. [15] Different organs of the plant may exhibit different phototropic reactions to different wavelengths ...
In general, cellular response to stimuli is defined as a change in state or activity of a cell in terms of movement, secretion, enzyme production, or gene expression. [9] Receptors on cell surfaces are sensing components that monitor stimuli and respond to changes in the environment by relaying the signal to a control center for further ...
Photosynthesis occurs in two stages. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the hydrogen carrier NADPH and the energy-storage molecule ATP. During the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide.
The length of light exposure influences entrainment. Longer exposures have a greater effect than shorter exposures. [12] Consistent light exposure has a greater effect than intermittent exposure. [14] In rats, constant light eventually disrupts the cycle to the point that memory and stress coping may be impaired. [15]
Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
A diagram of the Hill reaction which shows with the usage of an artificial electron acceptor such as DCPIP, and the chloroplast is subjected to light there is a release of oxygen, Also with the absence of CO 2 there is no sugar production A diagram of the Hill reaction taking place under dark conditions there is no oxygen emitted and the no ...