Answer to Question #194742 in Biochemistry for Kei

Question

1. Is the blood–brain barrier permeable to insulin? Explain.

2. Caffeine is a diuretic. What effect will drinking a lot of coffee have on the specific gravity of your urine?

3. What happens to the oxygen-carrying capacity of hemoglobin when the pH is lowered? What is the name of this effect?

Answer 1

1)Produced nearly exclusively by the pancreas, insulin crosses the blood-brain barrier (BBB) using a saturable transporter, affecting feeding and cognition through CNS mechanisms largely independent of glucose utilization.

2)Drinking caffeine-containing beverages as part of a normal lifestyle doesn't cause fluid loss in excess of the volume ingested. While caffeinated drinks may have a mild diuretic effect — meaning that they may cause the need to urinate — they don't appear to increase the risk of dehydration.

3)That is, the Bohr effect refers to the shift in the oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the environment.