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  2. Photosynthesis - Wikipedia

    en.wikipedia.org/wiki/Photosynthesis

    While able to perform photosynthesis, many of these eukaryotic groups are mixotrophs and practice heterotrophy to various degrees. Photosynthetic prokaryotic lineages Early photosynthetic systems, such as those in green and purple sulfur and green and purple nonsulfur bacteria , are thought to have been anoxygenic , and used various other ...

  3. Tears - Wikipedia

    en.wikipedia.org/wiki/Tears

    The functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. [3] Tears also occur as a part of the body's natural pain response. [4] Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional ...

  4. Photosynthetic pigment - Wikipedia

    en.wikipedia.org/wiki/Photosynthetic_pigment

    Chlorophyll a is the most common of the six, present in every plant that performs photosynthesis. Each pigment absorbs light more efficiently in a different part of the electromagnetic spectrum . Chlorophyll a absorbs well in the ranges of 400–450 nm and at 650–700 nm; chlorophyll b at 450–500 nm and at 600–650 nm.

  5. Photoautotroph - Wikipedia

    en.wikipedia.org/wiki/Photoautotroph

    These organisms perform photosynthesis through organelles called chloroplasts and are believed to have originated about 2 billion years ago. [1] Comparing the genes of chloroplast and cyanobacteria strongly suggests that chloroplasts evolved as a result of endosymbiosis with cyanobacteria that gradually lost the genes required to be free-living.

  6. Ecosystem respiration - Wikipedia

    en.wikipedia.org/wiki/Ecosystem_respiration

    The two main processes that contribute to ecosystem respiration are photosynthesis and cellular respiration. Photosynthesis uses carbon-dioxide and water, in the presence of sunlight to produce glucose and oxygen whereas cellular respiration uses glucose and oxygen to produce carbon-dioxide, water, and energy.

  7. Chloroplast - Wikipedia

    en.wikipedia.org/wiki/Chloroplast

    One of the main functions of the chloroplast is its role in photosynthesis, the process by which light is transformed into chemical energy, to subsequently produce food in the form of sugars. Water (H 2 O) and carbon dioxide (CO 2) are used in photosynthesis, and sugar and oxygen (O 2) are made, using light energy.

  8. Photosystem - Wikipedia

    en.wikipedia.org/wiki/Photosystem

    The two photosystems originated from a common ancestor, but have since diversified. [ 4 ] [ 5 ] Each of the photosystem can be identified by the wavelength of light to which it is most reactive (700 nanometers for PSI and 680 nanometers for PSII in chloroplasts), the amount and type of light-harvesting complex present, and the type of terminal ...

  9. Chlorophyll a - Wikipedia

    en.wikipedia.org/wiki/Chlorophyll_a

    Chlorophyll a is very important in the energy phase of photosynthesis. Two electrons need to be passed to an electron acceptor for the process of photosynthesis to proceed. [5] Within the reaction centers of both photosystems there are a pair of chlorophyll a molecules that pass electrons on to the transport chain through redox reactions. [20]