Erythrocytes

Heamoglobin has 4 polypeptide chains, two identical a- chains and two identical p chains.

Iron (Fe²⁺) of Hb is bound to histidine & four pyrrole rings.

B i.e. Inhibit heme oxygenase

Tin & Zn porphyrins and mesoporphyrins inhibits the activity of heme oxygenase Q and decrease formation of bilirubin Best method for Estimation of .Hb come in blood is – Cyanmethhemoglobin methodQ

B i.e. HgF

2,3. DPG does not combine with fetal hemoglobin

2,3DPG & Hemoglobin

2,3 DPG is present in high concentration in erythrocytes (HbA> HbA2)

2,3 DPG greatly reduces the affinity of Hb to O₂ Q (shifts O₂-dissociation curve to right)

Fetus Hb (HbF) consists of a2Y2, this tetramer has much lower affinity for 2-3 DPG than adult HbQ Corresponding a higher affinity for O₂.

Ans. is ‘a’ i.e., Flat bones

Ans. is ‘c’ i.e., 36 weeks gestation

Fetal Hb                       (a272)

Adults Hb                    (a2

o During the initial fetal life, the major hemoglobin synthesized in the body is fetal hemoglobin, because in fetus, the chain synthesized predominantly is the 7 chain.

• 13 chain is present in only trace amount in early embryos
• The rate of synthesis of y and 13 chains and the amount of HbA and HbF are inversely related during intrauterine stage.

o As the age of the fetus increases, the synthesis of 13 chains and the amount of adult hemoglobin in the blood increases

o At 36 weeks of gestational age the rate of synthesis of 13 chain exceeds that of y chain. This is called switch over.

Ans. A: HbA

In the embryo-Gower 1 (C₂ r₂) Gower 2 (a2E2)

In the fetus: hemoglobin F (a2y2)

In the adults:

Hemoglobin A (GA) – The most common with a normal amount over 95%

Hemoglobin A 2 (a₂6,) – Chain synthesis begins late in the third trimester and in adults, it has a normal range of 1.5-3.5%

Hemoglobin A1c is increased in the patients with poorly controlled diabetes mellitus

Ans. is ‘a’ i.e., 1

Hemoglobin is the most important red cell constituent.

The hemoglobin molecule is an assembly of four globular protein.

Each subunit is composed of a protein (polypeptide) part, i.e., globin and a nonprotein part i.e., heme, i.e., Each hemoglobin molecule contains four heme units and two pairs of similar protein, globin.

The heme part of globular protein is same in all types of hemoglobin.

The protein part vary in different hemoglobin : ‑

1.  Adult hemoglobin (Hemoglobin A) consist of two identical a-chains and two identical n-chains.
2. Fetal hemoglobin (H bF) consists of two identical a-chains and two identical y chains.
3. Minor hemoglobin (HbA₂) consist of two identical a-chains and two identical 8 chains.

Each hemoglobin molecule consists of globin (4 polypeptide chains) and 4 heme molecules.

Ans. is ‘b’ i.e., Low affinity for 2,3 DPG

Make it very clear in mind that higher affinity of fetal hemoglobin for oxygen is due to low affinity of HbF for 2,3­DPG (not due to decreased 2, 3-DPG concentration). HbF does not combines to 2, 3-DPG as avidly as adult hemoglobin.

Ans. is ‘d’ i.e., 4

• Hemoglobin is a conjugated protein which has a tetrameric structure.
• It is an assembly of four globular proteins.
• Each subunit is composed of a protein part, i.e. globin and a nonprotein prosthetic group, i.e. heme.
• Each hemoglobin molecule is made up of 4 heme molecules and 4 polypeptide chains (2 pairs of similar polypeptide chains).

Hemoglobin=Globin (containing 4 polypeptide chains)+ 4 heme molecules

Ans. is ‘a’ i.e., Each hemoglobin molecule is made of 4 polypeptides of each subunit