A gateway substance is something that may be menial but could lead to something bigger, an example is weed in the drugs world, weed is not hard to get and is usually a gateway drug to stronger types of drugs and potentially more dangerous
Answer:
It is believed that insects are so successful because they have a protective shell or exoskeleton, they are small, and they can fly. Their small size and ability to fly permits escape from enemies and dispersal to new environments. ... In addition, insects can produce large numbers of offspring relatively quickly.
The pKa represents the pH of the medium at which the zwitterionic amino acid assumes most stable ionic form due to structural stabilization. As the pKa is dependent upon the environmental factors of the solution around the amino acids, a change in their structure and localization can cause change in the pKa of the protein. Thus, the answers can be found as below:
Part A: Decrease (As the lysine is basic in nature, it will tend to stabilize the electrostatic interaction and weak interactions between the acidic amino acids and hydrogen bonds in the viscinity, thus lowering the pH and hence pKa of the protein)
Part B: Increase (As the carboxyl group is acidic in nature, removal of it will tend to increase the pKa since the basic amino acids will tend to accumulate more negative charge in their viscinity)
Part C: Increase (As glutamic acid is an acidic amino acid, its shift from outside to a non-polar site will prevents its ionization and hence the pKa will tend to shift from slightly acidic to slightly basic, hence increase)
If a bacterium cannot use citrate agar will not change its color (stays green). On the other hand, if bacteria have the ability to use citrate, the medium will change its color from green to blue.
This happens because citrate agar contains pH indicator such as bromothymol blue which transforms from green to blue in alkaline conditions.
The Pathway
• air enters the nostrils
•passes through the nasopharynx
•the oral pharynx
•through the glottis
• into the trachea
• into the right and left bronchi, with branches and rebranches into
• bronchioles each of which terminates in a cluster
• alveoli
