The events of inspiration begins with the;
Impulses are conducted on the phrenic nerve to muscle fibers in the diaphragm contracting them.
As the dome shaped diaphragm moves downward the thoracic cavity expands.
At the same time the external intercostal muscles may contract raising the ribs and expanding the thoracic cavity further.
The intra-alveolar pressure decreases
Atmospheric pressure greater than intra-alveolar pressure forces the air into the respiratory tract through the air passages.
The lungs fill with air.
Answer:
mostly hydrophobic
Explanation:
A membrane is made of amphipathic molecules with the hydrophobic part pointing to the lumen and cytosol and the hydrophobic part (much bigger makes up most of the membrane) in the middle, the protein chains that are embedded in the membrane are thus mostly hydrophobic because the membrane is mostly hydrophobic and like likes like
General transcription factors are involved in the formation of a preinitiation complex. The most common are abbreviated as TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH
Answer:
READ THIS
Explanation:
To understand how gene expression is regulated, we must first understand how a gene codes for a functional protein in a cell. The process occurs in both prokaryotic and eukaryotic cells, just in slightly different manners.
Prokaryotic organisms are single-celled organisms that lack a cell nucleus, and their DNA therefore floats freely in the cell cytoplasm. To synthesize a protein, the processes of transcription and translation occur almost simultaneously. When the resulting protein is no longer needed, transcription stops. As a result, the primary method to control what type of protein and how much of each protein is expressed in a prokaryotic cell is the regulation of DNA transcription. All of the subsequent steps occur automatically. When more protein is required, more transcription occurs. Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level.
Eukaryotic cells, in contrast, have intracellular organelles that add to their complexity. In eukaryotic cells, the DNA is contained inside the cell’s nucleus and there it is transcribed into RNA. The newly synthesized RNA is then transported out of the nucleus into the cytoplasm, where ribosomes translate the RNA into protein. The processes of transcription and translation are physically separated by the nuclear membrane; transcription occurs only within the nucleus, and translation occurs only outside the nucleus in the cytoplasm. The regulation of gene expression can occur at all stages of the process (Figure 1). Regulation may occur when the DNA is uncoiled and loosened from nucleosomes to bind transcription factors (epigenetic level), when the RNA is transcribed (transcriptional level), when the RNA is processed and exported to the cytoplasm after it is transcribed (post-transcriptional level), when the RNA is translated into protein (translational level), or after the protein has been made (post-translational level).
