Answer:
Option A, Hormones are controlled by a feedback loop; information about a system is sent back to the controller of the system to improve its function.
Explanation:
Negative feedback loop controls the hormone production and release. This is done by eliciting the release of substances till a certain level after which the stop signal is activated thereby preventing further release. By this method, concentration of hormones in blood is maintained within the narrow range.
For example – Thyroid hormones is released when the anterior pituitary signals the thyroid. This continues till the hormones in the blood reach the threshold level. Once the threshold level is reached, hypothalamus receives a feedback and then signals anterior pituitary to inhibit further signaling to the thyroid
Hence, option A is correct
Answer:
DNA replication is faster and microscopic in size, smaller than eukaryotic cell.
Explanation:
The three domains of life are archaea, bacteria and eukarya. The two main biological division are prokaryotes and eukaryotes. The organisms that lacks the complete nucleus are included in prokaryotes.
The DNA replication is quite fast in prokaryotes as compared to eukaryotes because of small genome size, transcription is coupled with the translation and no post transcription modification is present in prokaryotes. The size of prokaryotes is quite small as compared with eukaryotes and shows the fast rate of diffusion.
Thus, the answer is option (a) and (c).
1. A mudslide wipes out the side of a thriving hill: This is negative as many trees and other organisms will get destroyed.
2. A volcano erupts, covering the nearby land with lava: This is negative as molten and extremely hot lava can cause serious damage to its surroundings.
3. A forest is rapidly growing new plant life: This is positive because new plants are being grown.
4. Humans remove wolves from a national park to protect surrounding homes: This is positive for humans because humans will be safe but it is negative for the eco system as removal of wolves can upset the eco system cycle.
5. A dam is built in the middle of a river ecosystem to supply water to a nearby town: This is positive for humans as a new water resource is being developed for humans but negative for aquatic organisms as the dam can hamper their ecosystem and can cause pollution in water.
A protein's secondary structure is characterized by beta pleated sheets and alpha helices; the primary structure of a protein is the order of amino acids in a polypeptide, which is coded for the DNA of a gene. the secondary structure itself results from Hydrogen bonds, where the electronegative nitrogen and O2 atoms impart the hydrogen atoms with a semi positive charge.
