CH 6 Hemoglobin

What are the 2 types of globin chains that are produced? What chromosomes are their genes found on?

Alpha-like (alpha, and zeta); Chromosome 16

Nonalpha (beta, delta, epsilon, gamma); Chromosome 11

What state must iron be in order for oxygen to bind to Hgb?

Ferrous (Fe²⁺)

Review heme synthesis on Notes

Yes chef

What are the 3 embryonic types of Hgb and what are their chain components?

Gower I (zeta, epsilon)
Gower II (alpha, epsilon)

Portland (zeta, gamma)

What are the 3 Hgb groups observed in fetal, >1 year old, and adult life?

Hgb F (alpha, gamma)

Hgb A (alpha, beta)

Hgb A₂ (alpha, delta)

Describe the oxygen affinity and whether Hgb favors oxygen unloading/binding in the 1) T state (tense) 2) R state (rest)

T state: decreased oxygen affinity, favors unloading

R state: increased oxygen affinity, favors binding

What happens to H+, CO₂, T, and 2,3-DPG when

1. oxygen dissociation curve shifts right?

2. oxygen dissociation curve shifts left?

Right: everything increases (decreased O₂ affinity, favors unloading)

Left: everything decreases (increased O₂ affinity, favors binding)

What is the P₅₀ and what happens to it when it shifts left/right?

P₅₀ is the PO₂ in which Hgb is 50% saturated w/ O₂

P₅₀ increases as it shifts right, decreases as it shifts left

Describe the PO₂ , CO₂, H+, and Hgb activity in the lungs and tissues

lungs: High PO₂, low CO₂ and H+, Hgb becomes highly saturated

tissues: Low PO₂, high CO₂ and H+, Hgb released oxygen

What is the Bohr effect?

When increased CO₂ and H+ → decreased Hgb-O₂ affinity → promotes oxygen unloading in tissues

What is the Haldane effect?

When oxygenation of Hgb in lungs promotes CO₂ release (deoxygenated Hgb carries CO₂ form tissues → lungs)

What are the 3 forms in which CO₂ is transported from tissues to lungs?

bicarbonate (70%), Hgb bound (20-23%), dissolved in plasma (7-10%)

What is the relationship between 2-3 DPG and Hgb F?

Hgb F has a lower binding strength to 2-3 DPG compared to Hgb A. Therefore Hgb F has a higher affinity for O₂

What are the definitions of hypoxia and cyanosis?

hypoxia: inadequate O₂ to the tissues

cyanosis: bluish skin color due to >5 g/dL of deoxyhemoglobin in the blood

What are the definitions of Methemoglobin, Sulfhemoglobin, and Carboxyhemoglobin? How do they affect the oxygen dissociation curve?

1. Methemoglobin: Hgb iron in ferric state. Shifts curve left (due to other heme sites attempting to retain their O₂ and increasing affinity)

2. Sulfhemoglobin: Sulfur combined with Hgb. Shifts curve right (as Hgb can’t retain its O₂ as easily)

3. Carboxyhemglobin: CO binds to heme instead of O₂. Shifts curve left (due to other heme sites attempting to retain their O₂ and increasing affinity)