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The chloroplast is enclosed by a membrane. This membrane is composed of a phospholipid inner membrane, a phospholipid outer membrane, and an intermembrane space. Enclosed by the membrane is an aqueous fluid called the stroma. Embedded within the stroma are stacks of thylakoids (grana), which are the site of photosynthesis.
All organisms produce a phosphate compound, ATP, which is the universal energy currency of life. In photophosphorylation, light energy is used to pump protons across a biological membrane, mediated by flow of electrons through an electron transport chain. This stores energy in a proton gradient.
C 4 plants have a competitive advantage over plants possessing the more common C 3 carbon fixation pathway under conditions of drought, high temperatures, and nitrogen or CO 2 limitation. When grown in the same environment, at 30 °C, C 3 grasses lose approximately 833 molecules of water per CO 2 molecule that is fixed, whereas C 4 grasses
During the second stage, the light-independent reactions use these products to fix carbon by capturing and reducing carbon dioxide. The series of biochemical redox reactions which take place in the stroma are collectively called the Calvin cycle or light-independent reactions .
These plants differ from C3 plants because CO 2 is initially converted to a four-carbon molecule, malate, which is shuttled to bundle sheath cells, released back as CO 2 and only then enters the Calvin Cycle. In contrast, C3 plants directly perform the Calvin Cycle in mesophyll cells, without making use of a CO 2 concentration method. Malate ...
Calvin–Benson cycle. C 3 carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, the other two being C 4 and CAM.This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction:
Photosystem II (of cyanobacteria and green plants) is composed of around 20 subunits (depending on the organism) as well as other accessory, light-harvesting proteins. Each photosystem II contains at least 99 cofactors: 35 chlorophyll a, 12 beta-carotene , two pheophytin , two plastoquinone , two heme , one bicarbonate, 20 lipids, the Mn
Their life-cycle is strongly dominated by the haploid gametophyte generation. The sporophyte remains small and dependent on the parent gametophyte for its entire brief life. All other living groups of land plants have a life cycle dominated by the diploid sporophyte generation. It is in the diploid sporophyte that vascular tissue develops.