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.
Answer:
electrochemical
Explanation:
Dendrites are branched protoplasmic fingerlike projections extending from a nerve cell whose main function is to communicate the electrochemical stimulation(message) received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.
Answer:
Placebo, Is used to describe a substance given in clinical trial that does not contain the drug.
Explanation:
- Clinical trials are done to evaluate the effectiveness of a drug in treating a particular medical symptom or disease.
- In such case a placebo is used as a control in the experiment.
- A placebo contains all the components as the medicine except for the drug that is being tested.
- A placebo is given to one group of patients having the symptoms for which the drug is tested while another group of patients with same symptoms are given the drug.
- If the group that was given the drug show symptoms of cure while the group that was given placebo does not show changes. Then the drug is said to be effective.
The question is incomplete as it does not have the options which are:
- there was no sulfur compound added to the medium, that could be used as an electron donor.
- no oxygen was added to the medium so the organism died.
- there is some inhibitory chemical that is preventing the growth of the bacterium.
- you were using the wrong type of sunlight as the energy source for the bacterium.
Answer:
There was no sulfur compound added to the medium, that could be used as an electron donor.
Explanation:
In the given question, the bacteria which are found in the pond uses light energy to use carbon dioxide and form the glucose molecule. These bacteria are known as phototrophic bacteria.
The process of photosynthesis requires an electron donor and an electron acceptor to use molecule.
The organism when provided the light and carbon dioxide artificially in a culture, the bacteria were not able to grow. The reason for this could be accounted as that there was no electron donor found in the media like sulfur which could donate the electron during the chain reaction.
Thus, the selected option is correct.
