Answer: Components of cell junctions
Explanation:
<u>Fibroblasts are cells located in the dermis,</u> responsible for the formation and remodeling of tissue. They synthesize fibers and maintains the extracellular matrix of the tissue of animals. So, t<u>he extracellular matrix is a structurally complex entity that surrounds and supports the cells found in tissues</u>.
A cell junction a structure that exists within the tissues of animals and they consist of protein complexes that provide contact between cells or between a cell and the extracellular matrix. So if the cells do not appear flattened and do not attach to the extracellular matrix, then there is a problem with the components of cell junctions, which are mostly proteins as it was said before. And since proteins are coded by genetic information stored in DNA, then if there is a mutation in any of those genes, the fibroblast will fail to attach because the protein of the cell junction will be abnormal.
The surface of the early Earth is often described as hellish by scientists. The high temperature is primarily attributed to the high levels of carbon dioxide in the atmosphere and the molten rock on the surface of the planet. However, these two aren't the only factors in play.
Another factor that contributed to the extremely high temperature of the early earth is radioactivity. Radioactive decay of the isotopes found underground plus the left over heat from the formation of our planet produced high levels of radiogenic heat.
There's also the kinetic energy from falling asteroids and meteorites. Massive amounts of energy in the form of heat and sound is produced when asteroids and meteorites hit the Earth. Also, the pressure waves that travel radially outwards the center of the impact is similar to the impact of an atom bomb. As such, dust particles envelop the atmosphere, trapping the heat from the impact.
The last factor is the gravitational contraction, it contributed to the hellish temperature of primordial Earth because the energy generated from such event is enough to trigger hydrogen fusion.
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.
Answer:
2.compare a layer at one location to layers at other locations
Explanation:
Comparing rock layers in distant places can be a challenge for geologists since these layers may have different environmental factors that caused different transformations in them.
Therefore, when it is necessary to establish a comparison between layers of rocks in different ligands, geologists must establish steps to make an efficient comparison and have results consistent with reality. To do this, they must first compare a layer in one location with layers in other locations, assign relative age to a layer in one location, and identify index fossils in one or more layers in one location.
Answer:
Electron microscope
Explanation:
Instead of using light, it utilized a beam of electron for illumination. Because an electron beam has a shorter wavelength than light (up to 100, 000 times shorter), they have a higher resolution power and are therefore able to view sub-cellular structures including DNA.
