histone / histones. Under the microscope in its extended form, chromatin looks like beads on a string. The beads are called nucleosomes. Each nucleosome is made of DNA wrapped around eight histone proteins that function like a spool and are called a histone octamer.he beads are called nucleosomes. Each nucleosome is made of DNA wrapped around eight histone proteins that function like a spool and are called a histone octamer.
Definition. A hemoglobin test measures the amount of hemoglobin in your blood. Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs. If a hemoglobin test reveals that your hemoglobin level is lower than normal, it means you have a low red blood cell count (anemia). Anemia can have many different causes, including vitamin deficiencies, bleeding and chronic diseases.
A secondary function of hemoglobin is as part of the blood buffer system. The histidine residues in the globin chains act as weak bases to minimize the change in blood pH that occurs as oxygen is absorbed and carbon dioxide released in the lungs and as oxygen is delivered and carbon dioxide taken up from the tissues.b, Hbg, Hgb. The iron-containing pigment of red blood cells (RBCs) that carries oxygen from the lungs to the tissues. The amount of hemoglobin in the blood averages 12 to 16 g/100 ml in women, 14 to 18 g/100 ml in men, and somewhat less in children.