A pentapeptide found in this fluid in humans acts as a stronger natural opioid than morphine. For 10 points each:
[10m] Name this protein-rich fluid that contains most of the body’s amylase.
ANSWER: saliva [prompt on spittle]
[10e] Saliva is also rich in the glycoproteins that constitute this gel-like substance which lubricates membranes in the digestive and respiratory system.
ANSWER: mucus [or mucins or mucus membranes; prompt on phlegm; prompt on snot]
[10h] Another glycoprotein in human saliva, haptocorrin, binds tightly to this compound to protect it from digestion. As this compound cannot be biosynthesized, it is the “extrinsic” factor that is transferred to a glycoprotein called the “intrinsic” factor in the stomach.
ANSWER: vitamin B12 [or cobalamin; or cyanocobalamin or adenosylcobalamin or methylcobalamin]
<Adam Silverman, Science - Biology> ~20897~ <Editor: Adam Silverman>