In the Golgi body, the cell’s proteins and lipids are processed and packaged before being sent to their final destination. The Golgi apparatus is a series of flattened sacs, usually curled at the edges. Cisternae are spaces within the folds of the ER membranes.Īnother organelle is the Golgi apparatus (also called Golgi body). Within the ribosomes, amino acids are actually bound together to form proteins. The rough ER is the site of protein synthesis in a cell because it contains ribosomes however, the smooth ER lacks ribosomes and is responsible for producing lipids. In some places, the ER is studded with submicroscopic bodies called ribosomes. The ER is a series of membranes extending throughout the cytoplasm of eukaryotic cells. One example of an organelle is the endoplasmic reticulum (ER). Within the cytoplasm of eukaryote cells are a number of membrane-bound bodies called organelles (“little organs”) that provide a specialized function within the cell. Essentially, cytoplasm is the gel-like material enclosed by the plasma membrane. The “Movement through the Plasma Membrane” section later in this chapter describes the process by which materials pass between the interior and exterior of a cell.Īll prokaryote and eukaryote cells also have cytoplasm (or cytosol), a semiliquid substance that composes the volume of a cell. Within the fluid mosaic structure, proteins carry out most of the membrane’s functions. The membrane is therefore referred to as a fluid mosaic structure. ![]() Proteins embedded in the bilayer appear to float within the lipid, so the membrane is constantly in flux. The lipids occur in two layers (a bilayer). The plasma membrane is composed primarily of proteins and lipids, especially phospholipids. The plasma membrane (also known as the cell membrane) is the outermost cell surface, which separates the cell from the external environment. Examples of eukaryotes are protists, fungi, plants, and animals (everything except prokaryotes).Īll prokaryote and eukaryote cells have plasma membranes. Examples of prokaryotes are bacteria and archaea. Prokaryotic cells lack internal cellular bodies (organelles), while eukaryotic cells possess them. For example, prokaryotic cells lack a nucleus, while eukaryotic cells have a nucleus. However, the cells of prokaryotes are simpler than those of eukaryotes. The cells of all prokaryotes and eukaryotes possess two basic features: a plasma membrane, also called a cell membrane, and cytoplasm. ![]() The Structure of Prokaryote and Eukaryote Cellsĭuring the 1950s, scientists developed the concept that all organisms may be classified as prokaryotes or eukaryotes. Introduction to Nutrition and Digestion. ![]()
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