Question 1

The diatoms

Accepted Answer

Diatoms are primary producers, meaning they are capable of photosynthesis and are at the bottom of the food chain in many aquatic ecosystems.

Answer: B
 Diatoms form cell walls containing silica, not calcium carbonate.

A) is incorrect because diatoms do not use flagella for movement, they use a process called gliding.

C) is incorrect because diatoms can be found in many different aquatic environments, including freshwater and coastal waters.

E) is incorrect because diatoms are responsible for a significant amount of photosynthetic carbon fixation in the ocean.

Question 2

Which statement about dinoflagellates is false?

Accepted Answer

Dinoflagellates have a significant role in the corals' symbiotic relationship, providing a major source of food and energy for the coral.

Question 3

In alternation of generations, the

Accepted Answer

In alternation of generations, the diploid generation, known as the sporophyte, produces spores through meiosis.

Question 4

Which statement about oomycetes is false?

Accepted Answer

Oomycetes, often mistaken for fungi due to similar lifestyles, are actually more closely related to algae, specifically within the group Stramenopiles. This is a key distinction as it affects their classification and understanding of their evolutionary relationships.

Question 5

Which example best demonstrates the importance of sex (or genetic recombination) in protists?

Accepted Answer

Conjugation in Paramecium involves the exchange of genetic material, which is crucial for genetic diversity and long-term survival, as clones without it survive only a limited number of cell divisions.

Question 6

Which statement about brown algae is false?

Accepted Answer

Brown algae are not closely related to red algae; they are classified under the kingdom Chromista, while red algae belong to the kingdom Plantae.

Question 7

Which statement about foraminiferans is false?

Accepted Answer

Foraminiferans form shells primarily from calcium carbonate, not silica. Silica is more commonly associated with the shells of diatoms and radiolarians.

Question 8

You isolate an organism with two unequal flagella (one with hairs) that is encased in a shell made of silica.The group this organism most likely belongs to is the

Accepted Answer

Stramenopiles are characterized by having two unequal flagella, one of which is often hairy. Additionally, some stramenopiles, such as diatoms, are known for their silica shells, matching the description of the organism.

Question 9

Dinoflagellates have endosymbiotic relationships with corals.Corals cannot produce photosynthetic pigments, but they receive photosynthetic products from dinoflagellates.Which of the following might explain why corals are damaged or destroyed by excessive turbidity of ocean waters?

Accepted Answer

Turbid waters block sunlight from reaching photosynthesizing dinoflagellates, which reduces the amount of photosynthetic products that corals receive from their endosymbiotic dinoflagellates. This can lead to coral damage or destruction due to a lack of energy and nutrients from their dinoflagellate partners.

Question 10

Which structures are most likely to facilitate precise locomotion?

Accepted Answer

Rows of coordinated cilia can generate precise and coordinated movements, allowing for precise locomotion.

Question 11

Which features would most likely be characteristics of a protist with a multinucleate plasmodium that moves by cytoplasmic streaming and consumes yeasts, bacteria, and plant and animal remains via phagocytosis?

Accepted Answer

The characteristics described in the question, including a multinucleate plasmodium that moves by cytoplasmic streaming and consumes yeasts, bacteria, and plant and animal remains via phagocytosis, are typical of slime molds. Slime molds are heterotrophic and move slowly over moist surfaces like decaying logs and rocks.

Question 12

Refer to the figure of the cellular slime mold Dictyostelium.  What is occurring at arrows 1 and 3?

Accepted Answer

At arrow 1, feeding amoebas have run out of food and are beginning to aggregate, forming a mobile slug at arrow 3.

Quiz 26: The Origin and Diversification of Eukaryotes