Air pollution harms animals as a result of direct exposure to contaminants and destruction of their habitats, food and water sources. For instance, acid rain, which forms when pollutants in the... Air pollution harms animals as a result of direct exposure to contaminants and destruction of their habitats, food and water sources. For instance, acid rain, which forms when pollutants in the... Star Gazing
1 The cilia of the sensory neurons are immersed in a layer of mucus. 2  Odorant molecules (molecules that we can smell) dissolve in the mucus and. 3  bind to receptors on the cilia.4  These are 7-pass transmembrane proteins. 5  Binding of the odorant activates a G protein coupled to the receptor on its cytoplasmic side. bind to receptors on the cilia. 2  These are 7-pass transmembrane proteins. 3  Binding of the odorant activates a G protein coupled to the receptor on its cytoplasmic side. 4  This activates adenylyl cyclase, an enzyme embedded in the plasma membrane of the cilia.
Small nonpolar molecules such as molecular oxygen, carbon dioxide and molecules consisting of mostly hydrocarbons move through the membrane easily while polar molecules do not. Examples of polar molecules are monosaccharides, ions, AAs, and water. Large biological molecules such as proteins are way too large to cross the membrane. These large molecules are secreted from cells via exocytosis and frequently enter the cell via endocytosis..