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Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes , and is the place where almost all DNA replication and RNA synthesis ( transcription ) occur.
The cytoskeleton was once thought to be a feature only of eukaryotic cells, but homologues to all the major proteins of the eukaryotic cytoskeleton have been found in prokaryotes. [41] Harold Erickson notes that before 1992, only eukaryotes were believed to have cytoskeleton components.
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
Chloroplasts can be seen travelling around the central vacuole of a cell in Rhizomnium punctatum Cytoplasmic streaming in onion epidermal cell. Cytoplasmic streaming, also called protoplasmic streaming and cyclosis, is the flow of the cytoplasm inside the cell, driven by forces from the cytoskeleton. [1]
Oxygenic photosynthesis can be performed by plants and cyanobacteria; cyanobacteria are believed to be the progenitors of the photosystem-containing chloroplasts of eukaryotes. Photosynthetic bacteria that cannot produce oxygen have only one photosystem, which is similar to either PSI or PSII.
Desmin IFs are structural components of the sarcomeres in muscle cells and connect different cell organelles like the desmosomes with the cytoskeleton. [22] Glial fibrillary acidic protein (GFAP) is found in astrocytes and other glia. Peripherin found in peripheral neurons.
The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. [11] Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube.
This is one of two core processes in photosynthesis, and it occurs with astonishing efficiency (greater than 90%) because, in addition to direct excitation by light at 680 nm, the energy of light first harvested by antenna proteins at other wavelengths in the light-harvesting system is also transferred to these special chlorophyll molecules.