Indeed, steroid hormones have an important role in the well-being of the individual through specialized cells (having specific receptors). Take the example of vitamin D.
Vitamin D is involved in calcium and phosphorus absorption by the intestines, as well as in their reabsorption by the kidneys. It is involved also in bone mineralization of the skeleton and joints, as well as on muscle tone.
The mechanism of action of the hormone is identical to the scheme:
Its carrier is vitamin D-binding protein
The cell may be an intestinal cell, bone cells or renal cells.
The vitamin acts on the DNA is activating / inhibiting certain genes encoding proteins so as to increase the level of calcium in blood.
Answer:
The eclipse can only be viewed safely through a telescope using specialist solar filters. Solar viewer (also known as solar viewing glasses or solar eclipse glasses) are special eyewear designed for direct viewing of the Sun.
Answer:
C
Explanation:
Since the dark green phenotype allows the insects' to blend in with their surroundings, there will be generally more of the same dark green phenotype on the remote island. Since they are blending in with their surroundings, they survive easier, and they are able to stay alive long enough to reproduce. Let me know if this helped!
Answer:
The DNA strands are not free in the nucleus, but forming a compact structure called chromatin along special proteins, known as histones. The chromatin structure has an important role in gene expression, as the level of compaction and the histone modification act as signals for the transcription machinery
In order to be transcribed, different areas in the genome need to unfold from the histone proteins, so the RNA polymerase can access the DNA.
That means, <u>that DNA sequences that transcribe at high rate, are more often unfold from the histones, and more exposed to other proteins to bind them. Particularly, those areas are more sensitive to the attack of endonucleases, such as DNAse I.</u>
As a consequence, an assay of DNAse I digestion can be used to identify highly sensitive or resistant to DNAse cleavage areas in the genome, and therefore serve as an insight to which sequences are more and less transcriptionally active.
