why is haemoglobin red?

Question

the question is not why blood is red which is because of haemoglobin but specifically why is haemoglobin red

Answer 1

Thats the iron in it'
WERE ALL RUSTY INSIDE!

Answer 2

Oxyhaemoglobin is red because it absorbs light, but reflects light that is red (around about 600 -700 nm). It has an iron atom that when attached to the oxygen molecule it "rusts". Deoxyhaemoglobin reflects on the blue end of the spectrum, hence blue blood when deoxygenated.

Answer 3

Hemoglobin is contained within the red blood cells (erythrocytes), giving blood its characteristic color It serves to transport oxygen from the lungs to the tissues. haemoglobin is a iron and thats why the blood gets its colour

Answer 4

It's not red only when oxygen binds to it and it becomes oxyhaemoglobin is it red. Haemoglobin is blue which explains why when someone has low oxygen levels they start to turn blue (Cyanosed)

Answer 5

Why Is Hemoglobin Red

Answer 6

That is the color of oxygenated hemoglobin because of the compound that is formed when it has the oxygen in chemical union with it.

Look at bugs - their blood is green because they use a copper compound instead of the iron that we use.

Answer 7

its chemical structure e.g. the iron atom absorbs the spectrum of light that is complementary to red.

Most metal-complexes have a color. Chlorophyll for example is green, its very similiar to haemogolin but it has a Magnesium atom in the center.

Answer 8

the chemical compound of hemoglobin contains iron. when hemoglobin takes up oxygen, the combination of iron and oxygen turn the hemoglobin red.

Answer 9

As above, and that compound is iron.

Iron rust=orange/red
Copper rust/patina=green

Answer 10

Hemoglobin or haemoglobin (frequently abbreviated as Hb) is the iron-containing oxygen-transport metalloprotein in the red cells of the blood in mammals and other animals. Hemoglobin in vertebrates transports oxygen from the lungs to the rest of the body, such as to the muscles, where it releases the oxygen load. Hemoglobin also has a variety of other gas-transport and effect-modulation duties, which vary from species to species, and which in invertebrates may be quite diverse.

The name hemoglobin is the concatenation of heme and globin, reflecting the fact that each subunit of hemoglobin is a globular protein with an embedded heme (or haem) group; each heme group contains an iron atom, and this is responsible for the binding of oxygen. The most common types of hemoglobin contains four such subunits, each with one heme group.

Mutations in the genes for the hemoglobin protein in humans result in a group of hereditary diseases termed the hemoglobinopathies, the most common members of which are sickle-cell disease and thalassemia. Historically in human medicine, hemaglobinopathies were the first diseases to be understood in mechanism of dysfunction, down to the molecular level.

Hemoglobin is synthesized in the mitochondria of the immature red blood cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow, when the nucleus has been lost. Even after the loss of the nucleus, residual ribosomal RNA allow further synthesis of Hb until the reticulocyte loses its RNA on entering the vasculature. Hemoglobin is chemically represented by (C2952H4664N812O832S8Fe4).
Structure

Heme groupThe hemoglobin molecule in humans is an assembly of four globular protein subunits. Each subunit is composed of a protein chain tightly associated with a non-protein heme group.

Each individual protein chain arranges in a set of alpha-helix structural segments connected together in a globin fold arrangement, so called because this arrangement is the same folding motif used in other heme/globin proteins such as myoglobin. This folding pattern contains a pocket which is suitable to strongly bind the heme group.

A heme group consists of an iron atom held in a heterocyclic ring, known as a porphyrin. This iron atom is the site of oxygen binding. The iron atom is bonded equally to all four nitrogens in the center of the ring, which lie in one plane. Two additional bonds perpendicular to the plane on each side can be formed with the iron to a fifth and sixth bonding position, one connected strongly to the protein, the other available for binding of an oxygen molecule. The iron atom may either be in the Fe2+ or Fe3+ state, but ferrihemoglobin (methemoglobin) (Fe3+) cannot bind oxygen.

The Fe2+ in hemoglobin may exist in either a high-spin (deoxygenated) or low-spin (oxygenated) state, according to population of the iron (II) d-orbital structure with its 6 available d electrons, as understood in crystal field theory. With the binding of an oxygen molecule as a sixth ligand to iron, the iron (II) atom finds itself in a octahedral field (defined by the six ligand points of the four porphyrin ring nitrogens, the histamine nitrogen, and the O2). In these circumstances, with strong-field ligands, the five d-orbitals (these are the “3d” orbitals of the iron) undergo a splitting in energy between two of the d-orbitals which point directly in the direction of the ligands (dz2 and dx2-y2 orbitals, hybridized in these circumstances into two eg orbitals), and three of the d-orbitals which are pointed in off-directions (the dxy ,dxz, and dyz, hybridized in these circumstances into three t2g orbitals).

When oxygen is bound to Fe2+ in heme, all 6 d-electrons of the iron atom are forced into the three lower-energy t2g orbitals, where they must all be paired (see crystal field theory for diagram). This produces the “low-spin” state of oxyhemoglobin. The sharp high-energy of transition between the t2g and empty eg states of d-orbital electrons in oxyhemoglobin is responsible for the bright red color of the substance. When oxygen leaves, the Fe2+ is allowed to move out of the porphyrin ring plane, away from its five ligands toward the empty space formerly occupied by the O2, and in these circumstances eg orbital energies drop and t2g electrons move into them. This causes the iron atom to expand and increase its net spin, as d-orbitals become populated with unpaired electrons. In these circumstances, the absorption spectrum becomes broader, with smaller transition levels, producing the dark color of deoxyhemoglobin.

In adult humans, the most common hemoglobin type is a tetramer (which contains 4 subunit proteins) called hemoglobin A, consisting of two α and two β subunits non-covalently bound, each made of 141 and 146 amino acid residues, respectively. This is denoted as α2β2. The subunits are structurally similar and about the same size. Each subunit has a molecular weight of about 16,000 daltons, for a total molecular weight of the tetramer of about 64,000 daltons. Hemoglobin A is the most intensively studied of the hemoglobin molecules.

The four polypeptide chains are bound to each other by salt bridges, hydrogen bonds and hydrophobic interaction. There are two kinds of contacts between the α and β chains: α1β1 and α1β2.