Transport of a substance from the lumen (cavity) of an organ into one side of a cell and out the other side of the cell into the extracellular fluid is called <u>transcellular transport</u>.
The two routes of transport of substances across the epithelium of the gut are by transcellular method and paracellular method.
Transcellular transport refers to the transport of solutes across a epithelial cell layer through the cells. The best example is the movement of glucose from the intestinal lumen to the extracellular fluid by the epithelial cells. The epithelial cells use the active transport to generate the transcellular transport. Active transport refers to the transport of substances from a region of its lower concentration to a region of its higher concentration against the concentration gradient using cellular energy.
Happens when a species or population dies out
electrons don't just fly off into space because charged particles attract each other, keep in mind that alike particles repel off each other.
electromagnetic forces hold the electrons in orbit around the nucleus in the center of the atom. As they move in a repetive motion, they stay close together to stay in line.
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The main difference would be that prokaryotic cells are thought to not have a "true nucleus", as well as only having one single floating strand of DNA/Chromatid. Eukaryotic cells have a nucleus as well as a nucleolus, and many strands of chromatid and DNA.
The Tasmanian tiger is extinct (wiped out 3,000 years ago).
The Amur leopard is endangered (only 20-30 remain in the wild).
Western Lowland gorillas are endangered (population is dropping and species is expected to disappear).
The Eastern gemfish is threatened (population hasn't drastically declined and conservation efforts are helping the population slowly recover).
The golden toad is extinct (no frogs have been found in over two decades).