At a po₂ of 70 mm hg and normal temperature and ph, hemoglobin is % saturated with oxygen. at a po₂ of 70 mm hg and normal temperature and ph, hemoglobin is % saturated with oxygen.
a) 75
b) 50
c) 10
d) over 90
e) 25

D) over 90

Explanation:

As we know, hemoglobin is the protein found in red blood cells that is in charge of oxygen transportation, and the relation between the percentage of oxygen that binds to hemoglobin and the partial pressure of oxygen in the blood can be represented through the oxygen - hemoglobin dissociation curve, as shown in the attached image.

As we can see in the image, the curve has a sigmoid shape, and this is due to the allosteric interactions between the subunits of the hemoglobin, which change their conformation with each oxygen molecule that binds in order to increase even more the oxgen affinity. This curve is constantly shifting to the right and to the left depending on the conditions of the blood, like temperature, pH, partial pressure of carbon dioxide and the concentration of diphosphoglycerate (DPG).

When the PO2 is around 70 mmHg, as we can see in the curve, the hemoglobin is saturated around 90% or more, reaching a plateu in the curve where the oxygen is not binding as fast anymore, because there are almost no more free binding sites left in the hemoglobin molecule.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

the answer is c. it will give up it's valence electron to the other atom.