Tutor profile: Kim B.
Subject: Environmental Science
What are the types of population growth?
Logistic and exponential growth, or the S-curve and J-curve are the two hypothetical types of population growth. Exponential growth of a population would occur if a species had no competition for resources, no disease, and no predators. Every generation of a species would grow larger because every organism would have access to what it needs. This growth is called the J-curve because on a graph, it looks like a J due to the exponential growth. Logistic growth of a population is what is typically found in populations, because most populations have limited resources, disease, and predators. This growth pattern is called the S-curve because it has an S shaped graph, In logistic growth, populations will begin growing exponentially, but will then begin to level off in accordance to the amount of resources available to the population.
Subject: Basic Chemistry
What is an acid and a base?
Acids and bases are determined by the pH of a substance.pH is determined by the percent of hydrogen and hydroxyl ions found in the substance. The pH scale runs from 1-14 with 1 being the strongest acid and 14 being the strongest base. In the middle of the scale is 7 which is considered neutral. The closer you get away from 7 towards 1 or 14, the more acidic (more hydrogen ions) or basic (more hydroxyl ions) the substance is.
What is the difference between bacteria and viruses?
Although they are both similar in the fact that they make us sick, their method of doing so is different from one another. Bacteria are living cells, while viruses are not and do not contain cells. Viruses carry DNA or RNA, but must have access to a host cell where it can inject its own DNA/RNA in order to take over the cell later allowing the infected cell to reproduce. Bacterial cells do not need these host cells as they are able to reproduce on their own. Bacteria are typically much larger than viruses, and their structure is different as well. Bacteria contains DNA or RNA floating within the cytoplasm of a capsule. Viruses contain their genetic information within a protein coated outer structure.