Use the Following Information to Answer the Question

question 68

Multiple Choice

Use the following information to answer the question.
"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)
Hemoglobin is ________.

• A) a tertiary protein with two polypeptides
• B) a quaternary protein with two polypeptides
• C) a tertiary protein with four polypeptides
• D) a quaternary protein with four polypeptides

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Definitions:

Compacted Clay

Clay soil that has been compressed, often leading to reduced water infiltration and aeration.

Pore Spaces

Voids or gaps between soil particles or rock, which can hold air or water and are critical for fluid flow and organisms.

Water Table

The level below which the ground is completely saturated with water, marking the boundary between the area's unsaturated soil and its aquifer.

Overpumping

Pumping of groundwater at a rate that causes severe lowering of the water table in the aquifer or other detrimental effects.