The nucleotide sequence on a section of
DNA where transcription begins is called a promoter.
To add, i genetics, a promoter is a region
of DNA that initiates transcription of a particular gene. Promoters are found along
the transcription beginning sites of genes, on the same strand and upstream on
the <span>DNA.</span>
Answer:
True
Explanation:
Some deviations from normal homeostasis activate the positive feedback loops to control the conditions which are otherwise regulated by negative feedback mechanisms.
For example, the blood levels of respiratory gases and H+ ions are regulated by a negative feedback system via chemoreceptors. The increased partial pressure of carbon dioxide gas and lowered pH or lowered partial pressure of oxygen in the blood are sense by central and peripheral chemoreceptors which in turn activate the neurons of the dorsal respiratory group (DRG).
The activated DRG triggers an increased in the rate and depth of the breathing to facilitate the inhalation of more oxygen and exhalation of CO2 to restore the normal levels.
However, hypocapnia inactivates the chemoreceptors and does not allow negative feedback to restore the normal CO2 levels in the blood.
Under such conditions, the positive feedback loop stimulates the DRG neurons more strongly in response to the increased partial pressure of CO2 above the normal levels than when the partial pressure of oxygen falls below the normal level. These dangerously lowered oxygen levels may also cause fainting.
The constant turnover of body tissues requires the <u>chemical energy </u>supplied by carbohydrates, proteins, and lipids.
<h3> What is Chemical energy?</h3>
- The bonds of chemical molecules contain energy.
- Exothermic reactions are those in which chemical energy is released during the reaction, frequently in the form of heat.
- Some of the heat energy needed for a reaction to continue can be stored as chemical energy in newly created bonds.
- The body transforms the chemical energy in food into heat and mechanical energy.
- At a power plant, coal's chemical energy is transformed into electrical energy. Through the process of electrolysis, the chemical energy in a battery can also generate electricity.
Learn more about chemical energy here:
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