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A granum (plural grana) is a stack of thylakoid discs. Chloroplasts can have from 10 to 100 grana. Grana are connected by stroma thylakoids, also called intergranal thylakoids or lamellae. Grana thylakoids and stroma thylakoids can be distinguished by their different protein composition.
Within the envelope membranes, in the region called the stroma, there is a system of interconnecting flattened membrane compartments, called the thylakoids.The thylakoid membrane is quite similar in lipid composition to the inner envelope membrane, containing 78% galactolipids, 15.5% phospholipids and 6.5% sulfolipids in spinach chloroplasts. [3]
Stroma, in botany, refers to the colorless fluid surrounding the grana within the chloroplast. [ 1 ] Within the stroma are grana (stacks of thylakoid ), the sub-organelles where photosynthesis is started [ 2 ] before the chemical changes are completed in the stroma.
All green parts of a plant contain chloroplasts as the color comes from the chlorophyll. [11] The plant cells which contain chloroplasts are usually parenchyma cells, though chloroplasts can also be found in collenchyma tissue. [185] A plant cell which contains chloroplasts is known as a chlorenchyma cell.
Chloroplasts are characterized by a system of membranes embedded in a hydrophobic proteinaceous matrix, or stroma. The basic unit of the membrane system is a flattened single vesicle called the thylakoid; thylakoids stack into grana. All the thylakoids of a granum are connected with each other, and the grana are connected by intergranal ...
Mitosis divides the chromosomes in a cell nucleus. During mitosis chromosome segregation occurs routinely as a step in cell division (see mitosis diagram). As indicated in the mitosis diagram, mitosis is preceded by a round of DNA replication, so that each chromosome forms two copies called chromatids.
Germ cells, or gametes, undergo meiosis, while somatic cells will undergo mitosis. After the cell proceeds successfully through the M phase, it may then undergo cell division through cytokinesis. The control of each checkpoint is controlled by cyclin and cyclin-dependent kinases. The progression of interphase is the result of the increased ...
For example, chloroplasts in plants and green algae have lost all phycobilisomes, the light harvesting complexes found in cyanobacteria, red algae and glaucophytes, but instead contain stroma and grana thylakoids. The glaucocystophycean plastid—in contrast to chloroplasts and rhodoplasts—is still surrounded by the remains of the ...