The plasma membrane or the cell
membrane is the one that protects the cytoplasm of a cell. It is mostly
composed of lipids and proteins. It has a phospholipid bilayer that controls
the entering and exiting of molecules in the cell and at the same time,
provides protection for the cell or plasma membrane. It has polar head and a
nonpolar tail. Proteins embedded within the phospholipid bilayer have the same
function of the plasma membrane that includes selective transport. The
phospholipid bilayer consists mainly of the lipid molecules.
The hemoglobin holoenzyme (active enzyme) is a complex of an iron ion and 4 subunits- 2 hemoglobin alpha and two hemoglobin beta. People with sickle cell disease have mutated beta hemoglobins. The mutation is a single nucleotide exchange, that changes the 6th amino acid of protein primary struture - a Glutamic acid into Valine. This one alteration changes the tree dimentional structure of hemoglobin beta so, that it forms lond fibres that disrupt the normal circular form of the red blood cells.
I personally think that it's C because all others r present......even D......because plants like climbers do curl around a tree trunk !!!
Answer:
The correct answer is ''METAPHASE I.''
Explanation:
Metaphase I is the stage in which chromosomal studies are generally performed, because its morphology is very clear. The chromosomes, moved by the mitotic spindle, are placed in the center, between the two asters and form the so-called metaphase plate, in which the chromosomes are positioned in such a way that the kinetochore of each sister chromatid are oriented towards the opposite poles. Keeping chromosomes on the cell equator implies a balance between the forces of the microtubules that tend to move the kinetochores toward opposite poles, so positioning them in the center involves a great deal of energy.In each kinetochore, between 20-30 microtubules can be anchored, which exert traction force towards the pole from which they come, so the metaphase plate is maintained by the balance between the opposite forces of the poles on the chromosomes, which hold their sister chromatids by centromeric cohesin.
"F many scientists conduct the same or similar experiments, and all obtain similar results a 'Scientific Law or Theory' can be written, which is a generally agreed-upon statement that explains and predicts how a natural phenomenon works
