Ribosomes build a cell

Ribosomes build a cell - metabolic functions in the cell...

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Ribosomes build a cell’s proteins. Ribosomes,  containing rRNA and protein, are the organelles that carry out protein  synthesis. Cell types that synthesize large quantities of proteins (e.g., pancreas cells) have large  numbers of ribosomes and prominent nucleoli. Some ribosomes, free ribosomes, are suspended in the cytosol and synthesize proteins that  function within the cytosol. Other ribosomes, bound ribosomes, are attached to the outside of the endoplasmic reticulum  or nuclear envelope. These synthesize proteins that are either included in membranes or exported from the cell. Ribosomes can shift between roles depending on the polypeptides they are synthesizing. Concept 7.4 The endomembrane system regulates protein traffic and performs
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Unformatted text preview: metabolic functions in the cell Many of the internal membranes in a eukaryotic cell are part of the endomembrane system. These membranes are either directly continuous or connected via transfer of vesicles, sacs of membrane. In spite of these connections, these membranes are diverse in function and structure. The thickness, molecular composition and types of chemical reactions carried out by proteins in a given membrane may be modified several times during a membrane’s life. The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and the plasma membrane....
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