Answer:
<u>The bacterial cell because it has the largest surface-to-volume-ratio.</u>
Explanation:
The rate of diffusion in and out of a body depends on surface area to volume ratio. The higher the ratio the greater the rate of diffusion and the lower the ratio, the lower the rate of diffusion.
This implies that small organisms like the bacteria cell expose a large surface area to the surrounding when compared to big organism cells. Therefore, small organisms depend on diffusion as a means of transport of foods, respiratory gases and waste products.
Large organisms, in addition to diffusion have trasnport systems to increase the efficiency of diffusion.
Answer:
A. Puffins receive energy from herring, herring receive energy from krill, and krill receive energy from phytoplankton.
Explanation:
A food chain represents the unidirectional network or path of the flow of energy and the matter in an ecosystem.
The aquatic food chain begins from the small or microscopic organisms called phytoplankton which is autotrophic therefore are considered the producers.
The phytoplanktons are eaten by a variety of other organisms in which the krills which live in the deep sea feeds on these phytoplanktons. The krills are the primary consumers who are eaten by small fish like herring which acts as secondary consumers. These herring are then eaten by the bird-like puffins and large fish which acts as tertiary consumers.
Thus, Option-A is the correct answer.
Answer:
- Alteration of an enzyme involved in folic acid synthesis
- A change in the structure of 23S rRNA
- The terminal D-alanine of pentapeptide mutates to D-serine
Explanation:
Antibiotic resistance is the phenomenon by which microorganisms naturally have, acquire, or develop the ability to defeat the drugs designed to eliminate them. For example, trimethoprim is able to bind with the enzyme dihydrofolate reductase (DHFR) in order to inhibit the folic acid synthesis pathway. Sulfonamides (sulfa drugs) competitively inhibit the incorporation of para-aminobenzoic acid (PABA) into folic acid and thus also prevent the synthesis of folic acid. Ribosomes are organelles where proteins are synthesized. The 23S rRNA is a component of the large subunit (50S) of bacteria and archaea ribosomes. In consequence, it is expected that a modification in the structure of 23S rRNA alters protein synthesis. Finally, vancomycin acts by binding the terminal D-Ala-D-Ala residues of the polymeric lipid-PP-disaccharide-pentapeptides and thus inhibits cell wall synthesis in Gram-positive bacteria. In consequence, it is expected that a mutation at the terminal D-alanine that modifies this sequence alters the vancomycin binding site and thus also confers antibiotic resistance.
