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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.
Electrons travel through the cytochrome b6f complex to photosystem I via an electron transport chain within the thylakoid membrane. Energy from PSI drives this process [ citation needed ] and is harnessed (the whole process is termed chemiosmosis ) to pump protons across the membrane, into the thylakoid lumen space from the chloroplast stroma.
Seen through a microscope, chlorophyll is concentrated within organisms in structures called chloroplasts – shown here grouped inside plant cells. Plants are perceived as green because chlorophyll absorbs mainly the blue and red wavelengths but green light, reflected by plant structures like cell walls, is less absorbed.
Palisade cells contain a high concentration of chloroplasts, particularly in the upper portion of the cell, making them the primary site of photosynthesis in the leaves of plants that contain them. Their vacuole also aids in this function: it is large and central, pushing the chloroplasts to the edge of the cell, maximising the absorption of ...
Excited chlorophyll dissipates the absorbed light energy by driving photosynthesis (photochemical energy conversion), as heat in non-photochemical quenching or by emission as fluorescence radiation. As these processes are complementary processes, the analysis of chlorophyll fluorescence is an important tool in plant research with a wide ...
The leaf is the primary site of photosynthesis in plants. There are four main factors influencing photosynthesis and several corollary factors. The four main are: [113] Light irradiance and wavelength; Water absorption; Carbon dioxide concentration; Temperature. Total photosynthesis is limited by a range of environmental factors.
This dimer is called a special pair because of its fundamental role in photosynthesis. This special pair is slightly different in PSI and PSII reaction centers. In PSII, it absorbs photons with a wavelength of 680 nm, and is therefore called P680. In PSI, it absorbs photons at 700 nm and is called P700. In bacteria, the special pair is called ...
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.