Answer: Pollination, the transfer of pollen from flower-to-flower in angiosperms or cone -to-cone in gymnosperms, takes place through self-pollination or cross-pollination.
Cross-pollination is the most advantageous of the two types of pollination since it provides species with greater genetic diversity.
Maturation of pollen and ovaries at different times and heterostyly are methods plants have developed to avoid self-pollination.
The placement of male and female flowers on separate plants or different parts of the plant are also barriers to self-pollination.
The advantage that is conferred to algae and plants that have sporopollenin is that they have reproductive cells that are more resistant to desiccation. Remember that a sporopollenin is a polymer that is inert and makes up the outer layer of pollen grains and spores. Sporopollenin<span> is also found in the cell walls of several taxa of green </span>alga<span>, including Phycopeltis </span>
Answer:
The modified hemoglobin with free imidazole cannot be expected to show cooperativity in oxygen binding. The movement of iron ion takes place up in the plane of heme when binding of one subunit of hemoglobin takes place with oxygen. One of the iron's and oxygen's axial ligands comprise the proximal histidine's imidazole ring.
With the movement of iron into the hemoglobin ring, the pulling of proximal histidine takes place along with it. Therefore, when binding of oxygen takes place with one subunit, a modification also takes place in the intersubunit associations, this also comprises displacement of the alpha helix. This phenomenon plays an essential role in modifying the hemoglobin's tensed state to the relaxed state. The withdrawal or mutation of the imidazole ring from the histidine residue does not further permit the cooperative binding as it is not associated physically with the alpha-helix.
The test that will most likely be prescribed is an Ultrasound Examination.
