![]() Patients suffering from celiac disease must follow a gluten-free diet. This leads to malnutrition, cramping, and diarrhea. ![]() The immune response damages microvilli, and thus, afflicted individuals cannot absorb nutrients. People with celiac disease have an immune response to gluten, which is a protein found in wheat, barley, and rye. ![]() This is an excellent example of form following function. Such cells are typically found lining the small intestine, the organ that absorbs nutrients from digested food. The plasma membranes of cells that specialize in absorption are folded into fingerlike projections called microvilli (singular = microvillus) ( Figure). The eukaryotic plasma membrane is a phospholipid bilayer with proteins and cholesterol embedded in it. Wastes (such as carbon dioxide and ammonia) also leave the cell by passing through the plasma membrane. The plasma membrane controls the passage of organic molecules, ions, water, and oxygen into and out of the cell. ![]() A phospholipid is a lipid molecule with two fatty acid chains and a phosphate-containing group. Like prokaryotes, eukaryotic cells have a plasma membrane ( Figure), a phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment. If the nucleolus were not able to carry out its function, what other cellular organelles would be affected? The Plasma Membrane Plant cells do not have lysosomes or centrosomes. The plant cell has a cell wall, chloroplasts, plastids, and a central vacuoleâstructures not found in animal cells. These figures show the major organelles and other cell components of (a) a typical animal cell and (b) a typical eukaryotic plant cell. Before turning to organelles, letâs first examine two important components of the cell: the plasma membrane and the cytoplasm. Organelles allow different functions to be compartmentalized in different areas of the cell. Because a eukaryotic cellâs nucleus is surrounded by a membrane, it is often said to have a âtrue nucleus.â The word âorganelleâ means âlittle organ,â and, as already mentioned, organelles have specialized cellular functions, just as the organs of your body have specialized functions.Īt this point, it should be clear to you that eukaryotic cells have a more complex structure than prokaryotic cells. Unlike prokaryotic cells, eukaryotic cells have: 1) a membrane-bound nucleus 2) numerous membrane-bound organelles such as the endoplasmic reticulum, Golgi apparatus, chloroplasts, mitochondria, and others and 3) several, rod-shaped chromosomes. Our natural world also utilizes the principle of form following function, especially in cell biology, and this will become clear as we explore eukaryotic cells ( Figure). For example, a skyscraper should be built with several elevator banks a hospital should be built so that its emergency room is easily accessible. In architecture, this means that buildings should be constructed to support the activities that will be carried out inside them. Have you ever heard the phrase âform follows function?â Itâs a philosophy practiced in many industries.
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