Which of the following statements best describes a feature of hemoglobin? A molecule of hemoglobin can bind up to four molecules of oxygen O Hemoglobin contains a large proportion of hydroxyproline and hydroxylysine residues The folding of the hemoglobin molecule is dependent on the four subunits One molecule of hemoglobin can transport proteins across a cellular membrane The Hill coefficient is a measure of the degree of cooperativity. If NH equals 1, Ligand binding is cooperative There is positive cooperativity Ligand binding is not cooperative There is negative cooperativity