When O2 binds to heme in hemoglobin, the ion is drawn into the plane of the porphyrin causing a conformational change that is transmitted to adjacent subunits enhancing the for additional O2 binding. Group of answer choices Fe2 ; affinity Mg2 ; folding Mg2 ; planarity Fe3 ; affinity

Fe2 ; affinity

Explanation:

Hemoglobin is the specialised protein which are present in red blood cells which gives it the ability to carry oxygen to the tissues and return carbondioxide from the tissues to the lungs.

The hemoglobin is made up of

--> a heme group: this consists of a ferrous iron ( Fe2) and a surrounding porphyrin ring.

--> globin.

As the haemoglobin molecule loads and unloads oxygen (O2) the individual globin chains in the hemoglobin molecule move on each other. When oxygen is unloaded the beta chains are pulled apart, permitting entry of the metabolite 2,3-diphosphoglycerate resulting in a lower affinity of the molecule for oxygen and higher affinity for carbondioxide.

Also, when the partial pressure of oxygen (PO2) in the blood is high, the beta chains move close together, O2 binds to heme in hemoglobin, the ion Fe2 is drawn into the plane of the porphyrin causing a conformational change that is transmitted to adjacent subunits enhancing the AFFINITY for additional O2 binding.

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.