Answer:
Hemoglobin is responsible for binding and transporting oxygen in the body. It is a tetrameric protein that is found in high concentration in red blood cells (erythrocytes, red blood cells). Each hemoglobin molecule is made up of four subunits: two of the alpha type and two of the beta type, and each subunit can bind an oxygen molecule through its heme group.
Structure studies have shown that hemoglobin can adopt two conformations, called T (tense) and R (relaxed). Deoxyhemoglobin (in blue) is in state T, and the union of oxygen (in red) causes the transition to state R. The animation shows a close view of the heme group (in white, balls and rods) of one of the subunits of hemoglobin. In the deoxygenated state (T), the iron atom is not coplanar with the rest of the heme group due to its association with the histidine side chain. The union of oxygen displaces the iron atom so that it remains coplanar with the rest of the heme group, which in turn drags histidine, producing a larger-scale conformational change that affects the entire protein.
Hemoglobin can be considered as a tetramer formed by two alpha-beta dimers. The conformational change associated with the transition from T to R mainly affects the relative position of these two dimers (rather than the interactions between the alpha and beta subunits within a dimer). This is illustrated in the last stretch of the animation (drawn in black and white).
<span>advancing mass of warm air, in particular, the leading edge of the warm sector of a low-pressure system.</span>
The function of microviilli is to absorb nutrients in the small intestine to absorb nutrients that were not absorbed in the small intestine...
Answer: Option B
Explanation:
Usually in scientific experiments, at least one parameter is checked; here, the growth rate of wheat in two different conditions is being evaluated.
Hence, growth rate of wheat alone in pans A, B and C becomes the standard or referential control against which the experimental control (Wheat + clover) in pans D, E and F is evaluated, since both treatments are exposed to the same external conditions.
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