Answer:
The ability of caffeine to inhibit adenosine receptors, plays a very important role in heightened alertness and sleeplessness.
Explanation:
"<em><u>Caffeine</u></em>" (<em>1,3,7-trimethylxanthine</em>) is an alkaloid obtained from plants. It has a chemical formula of C8H10N4O2.
Caffeine is generally <em>hydrophillic</em> but sufficiently <em>lipophilic</em> to pass through all biological membranes and readily cross the blood-brain barrier.
Therefore can bind with the adenosine receptors. Due to the blocking of adenosine inhibitory effects through its receptors held by paraxanthine and caffeine, it indirectly affects the release of <u>norepinephrine, dopamine, acetylcholine, serotonin, glutamate</u> e.t.c.
The release of the above-mentioned hormones have a great impact on the heightened alertness of the body, especially <em>dopamine</em> and <em>serotonin</em>.
B, ocean trenches are formed after a underwater volcano has erupted.<span />
Answer:
Both starch and cellulose are glucose polymers, but the glycosidic linkages in these two polymers differ, as shown in Figure 5.7. Glucose can have two slightly different ring structures. When glucose forms a ring, the hydroxyl group attached to the number 1 carbon is positioned either below (alpha)or above (beta) the plane of the ring. In starch, all the glucose monomers are in the alpha configuration (Figure 5.7b). In cellulose, all the glucose monomers are in the beta configuration. As a result, every other glucose monomer is "upside down" with respect to its neighbors (Figure 5.7c). The differing glycosidic linkages in starch and cellulose give the two molecules distinct three-dimensional shapes, leading to key functional differences.
Explanation:
Answer:
O A conclusion derived from evidence and logical robsoning
Explanation:
Effective against viruses.
