Question 1

What is an implication of the fact that tests were conducted after a period of dry weather?

Accepted Answer

The fact that tests were conducted after a period of dry weather indicates that there may be differences in the levels of endotoxins compared to a period of rainfall. If more periods of rainfall occur after the testing, the bacteria that secrete endotoxins may increase, thereby increasing endotoxin levels.

Question 2

Which of the following is a plausible reason for why it may be difficult to treat infections that arise from tooth decay?

Accepted Answer

The structure of the biofilm that causes tooth decay becomes larger and denser, making it difficult for antibiotics to penetrate the bacterial cell walls and reach the bacteria within the biofilm. This makes it more challenging to treat the infection effectively. The other options are not accurate or do not provide a plausible reason for the difficulty in treating infections related to tooth decay.

Question 3

According to this evolutionary tree,the archaea and eukaryotes last shared a common ancestor ________.

Accepted Answer

According to the evolutionary tree, the last shared ancestor of archaea and eukaryotes existed around 2.5 billion years ago, which is indicated by the branch point where these two domains of life split. The split between bacteria and archaea is thought to have occurred earlier, around 3.5 billion years ago. Therefore, option C is the correct answer.

Question 4

Which of the following is a colonial form of green algae?

Accepted Answer

Volvox is a colonial form of green algae, commonly found in freshwater ponds and streams. Giardia is a parasite, Paramecium is a single-celled organism, and Plasmodium causes malaria in humans.

Question 5

What kind of prokaryotes are these?

Accepted Answer

The answer of What kind of prokaryotes are these? 
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Question 6

A vector is an organism that transfers a pathogen to a host.In the case of malaria,the vector(s)is (are)________.

Accepted Answer

The vector for malaria is Anopheles mosquitoes only. Humans can be infected with the malaria parasite, but they do not transfer the pathogen to other humans or mosquitoes. The Plasmodium parasite is the pathogen that causes malaria, but it cannot be a vector since it is not an organism that can transfer the pathogen.

Question 7

What is a logical conclusion to draw from this study?

Accepted Answer

The study found that indoor air endotoxin levels were significantly higher in flood-damaged homes compared to non-damaged homes. Therefore, workers should be advised to wear protective respiratory gear to avoid inhaling harmful levels of endotoxins while working in these areas. The study did not provide information on outdoor air endotoxin levels or the development of irreversible lung infections in workers.

Question 8

Endosymbiosis explains the origin of the ________ of eukaryotes.

Accepted Answer

Endosymbiosis theory proposes that mitochondria and chloroplasts were once free-living bacteria that were engulfed by a larger host cell, eventually evolving into the current organelles found in eukaryotic cells. Therefore, endosymbiosis explains the origin of chloroplasts and mitochondria in eukaryotes.

Question 9

A photoautotrophic unicellular organism with a shell made of silica is most likely a(n)________.

Accepted Answer

Diatoms are unicellular photoautotrophic organisms with a unique cell wall made of silica, giving them a distinct appearance under microscopy. Apicomplexans, such as Plasmodium, are parasitic organisms that do not have a silica shell. Forams and dinoflagellates have shells made of calcium carbonate or cellulose, respectively.

Question 10

In the image above,the aquatic organism moves using flagella.It is parasitic and can colonate and reproduce in the human intestine.What type of organism could this be?

Accepted Answer

The description of the organism as a parasite and having flagella suggests that it is a protozoan, which is a unicellular organism that often moves using flagella. Slime mold, phytoplankton, and seaweed are not typically parasitic and do not commonly colonize and reproduce in the human intestine.

Question 11

If an area infested with female Anopheles mosquitoes is treated with pesticides,and these mosquitos live,continue to breed,and continue to spread malaria,what can we conclude?

Accepted Answer

The fact that the mosquitoes are living, breeding and spreading malaria despite the pesticide treatment suggests that there are alleles in the population that are resistant to the pesticide. These resistant individuals are more likely to survive and pass on their resistant genes to their offspring, resulting in a population that is increasingly resistant to the pesticide. This can make the pesticide ineffective in controlling the mosquito population and reducing the spread of malaria.

Question 12

What addition to methodology would be most beneficial to the study?

Accepted Answer

The addition of pre-flood data would allow for a more accurate comparison between endotoxin levels before and after the flood, providing a clearer understanding of the impact the flood had on endotoxin levels in the affected areas.

Question 13

What is a potential benefit of testing indoor and outdoor sites as well as sites with heavy flooding and light flooding?

Accepted Answer

Testing in multiple sites provides a wider range of data and allows scientists to compare endotoxin levels under different conditions, which can lead to a better understanding of how endotoxins behave in different environments.

Question 14

Suppose production of the pesticides used to treat malaria is halted because the Environmental Protection Agency (EPA)has found that they are causing too much environmental damage to warrant its continued use.In turn,this drives up the prices of artemisinin and quinine since they are now in higher demand.How might this affect those that live in South America and Africa?

Accepted Answer

With the halt in production of pesticides to treat malaria and an increase in demand for artemisinin and quinine, the prices of these drugs will increase. This will make it more difficult for people in South America and Africa, where malaria is prevalent, to access treatment, leading to an increase in the number of malaria cases.

Question 15

If you were to view this organism with the right microscope you could see that the entire stalk is covered with smaller hairs than the ones on the opening.What might be the function of these smaller hairs on the stalk?

Accepted Answer

The smaller hairs on the stalk might be used for movement, as they could assist the organism in navigating or anchoring itself in its environment.

Question 16

Plasmodium illustrate feeding characteristics of a(n)________.

Accepted Answer

Plasmodium is a genus of apicomplexan parasites, which are unicellular organisms that feed on their host's cells or bodily fluids.

Question 17

What accounts for the similarity between seaweeds and plants?

Accepted Answer

Seaweeds and plants share many similar characteristics, such as the presence of chlorophyll and cell walls made of cellulose. However, they evolved independently from different ancestors, indicating convergent evolution. This means that they developed similar characteristics due to adapting to similar environments and ecological pressures, rather than through a common ancestor.

Question 18

What kind of protist is this?

Accepted Answer

The answer of What kind of protist is this? 
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Quiz 15: The Evolution of Microbial Life