Question 1

Living diatoms contain brownish plastids.If global warming causes blooms of diatoms in the surface waters of Earth's oceans,how might this be harmful to the animals that build coral reefs?

Accepted Answer

The endosymbiotic dinoflagellates, commonly known as zooxanthellae, are photosynthetic algae that live inside the tissue of coral animals. They provide the coral with nutrients and energy through photosynthesis. If diatoms bloom in the surface waters, they may block some of the sunlight that the zooxanthellae need to photosynthesize, causing them to die or reduce their productivity. This would harm the coral animals and may lead to their death or bleaching.

Question 2

Previously understood similarities that seemed to connect slime molds and fungi are now considered to be ________.

Accepted Answer

Slime molds were previously thought to be part of the fungi kingdom due to similarities such as a spore-based reproduction and growth methods. However, recent genetic studies have shown that they are actually closer to amoebas than to fungi, making their similarities to fungi an example of convergent evolution rather than a true homology or variation of a common ancestral trait.

Question 3

A biologist discovers an alga that is marine,multicellular,and lives at a depth reached only by blue light.This alga probably belongs to which group?

Accepted Answer

Red algae are well adapted to deep water and are known to live at depths where only blue light can penetrate. They are also multicellular and marine, making them the best choice for this scenario. Brown algae and green algae can also be multicellular and marine, but they typically do not live at the depths that only blue light can reach. Dinoflagellates and golden algae are primarily unicellular and may not be well adapted to living in deep water.

Question 4

You are designing an artificial drug-delivery "cell" that can penetrate animal cells.Which of these protist structures should provide the most likely avenue for research along these lines?

Accepted Answer

The answer of You are designing an artificial drug-delivery "cell"...

Question 5

Unikonta is a supergroup that includes all of the following except ________.

Accepted Answer

Unikonta includes fungi, protists, and animals, but not plants.

Question 6

Which of the following is correctly described as a primary producer?

Accepted Answer

Diatoms are primary producers as they are photosynthetic organisms that directly convert energy from sunlight into organic compounds. Slime moulds, kinetoplastids, apicomplexans, and radiolarians do not carry out photosynthesis and are not primary producers.

Question 7

Similar to most amoebozoans,the forams and the radiolarians also have pseudopods,as do some of the white blood cells of animals (monocytes).If one were to erect a taxon that included all organisms that have cells with pseudopods,what would be true of such a taxon?

Accepted Answer

The taxon would be polyphyletic because it would include organisms from multiple evolutionary lineages that do not share a recent common ancestor, but have independently evolved the trait of having pseudopods.

Question 8

You are given the task of designing an aerobic,mixotrophic protist that can perform photosynthesis in fairly deep water (for example,250 m deep),and can also crawl about and engulf small particles.With which two of the following structures would you provide your protist?
1)hydrogenosome
2)apicoplast
3)pseudopods
4)chloroplast from red alga
5)chloroplast from green alga

Accepted Answer

For deep-water photosynthesis, chloroplasts from red algae are ideal because they can absorb light at longer wavelengths, which penetrates deeper into the water. Pseudopods would allow the protist to crawl and engulf particles, fitting the mixotrophic and mobile criteria.

Question 9

If the Archaeplastidae are eventually designated a kingdom,and if land plants are excluded from this kingdom,then what will be true of this new kingdom?

Accepted Answer

If land plants are excluded from the Archaeplastidae, then this new kingdom would be paraphyletic because it would not include all descendants of its common ancestor, as land plants are descendants of the common ancestor of the Archaeplastidae.

Question 10

Which of the following are actual mutualistic partnerships that involve a protist and a host organism?

Accepted Answer

A, B, and D describe mutualistic relationships involving protists. In these partnerships, both the protist and the host organism benefit from the relationship. For example, cellulose-digesting gut protists help wood-eating termites digest wood, dinoflagellates provide reef-building coral animals with nutrients through photosynthesis, and certain algae live in a mutualistic relationship with foraminiferans, providing them with energy through photosynthesis. Trichomonas and humans (C) do not have a mutualistic relationship; Trichomonas vaginalis is a pathogen in humans.

Question 11

A gelatinous seaweed that grows in shallow,cold water and undergoes heteromorphic alternation of generations is most probably what type of alga?

Accepted Answer

The description matches that of a brown alga, which commonly undergoes heteromorphic alternation of generations and includes species such as kelp that grow in shallow, cold water. Red and green algae also undergo alternation of generations, but the description of a gelatinous seaweed is more typical of brown algae. Yellow algae are not as commonly known for their alternation of generations, and the description of a gelatinous seaweed does not match their typical morphology.

Question 12

A snail-like,coiled,porous test (shell)of calcium carbonate is characteristic of which group?

Accepted Answer

The description of a snail-like, coiled, porous shell made of calcium carbonate is characteristic of foraminiferans, which are single-celled organisms with a test made of calcium carbonate. Diatoms have a hard outer wall made of silica, radiolarians have tests made of silica, and amoebas do not have shells.

Question 13

Reinforced,threadlike pseudopods that can perform phagocytosis are generally characteristic of which group?

Accepted Answer

The answer of Reinforced,threadlike pseudopods that can perform phagocytosis are...

Question 14

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

Accepted Answer

The most widely accepted theory is that chloroplasts of land plants were derived from an endosymbiotic event with cyanobacteria, which then evolved into green algae, and eventually gave rise to land plants.

Question 15

The chloroplasts of all of the following are thought to be derived from ancestral red algae,except those of

Accepted Answer

The answer of The chloroplasts of all of the following...

Question 16

Green algae differ from land plants in that many green algae

Accepted Answer

While some green algae may form multicellular colonies, the majority are unicellular. This distinguishes them from most land plants, which are multicellular.

Answer: C
 Like land plants, green algae have plastids, which are organelles that perform photosynthesis. In fact, it is believed that land plants evolved from a type of green algae.

Answer: D
 While some species of green algae have life cycles with both sexual and asexual phases, they do not have a complete alternation of generations like land plants do.

Answer: E
 Green algae (like most algae) have cell walls made of cellulose, but the specific composition and structure of their walls may be different than those of land plants.

Question 17

Which pair of alternatives is highlighted by the life cycle of the cellular slime moulds,such as Dictyostelium?

Accepted Answer

The life cycle of cellular slime moulds involves both unicellular and multicellular stages. The individual cells initially live independently as unicellular amoebae and later aggregate to form a multicellular structure, which operates as a single organism. This cycle highlights the duality of the slime moulds as both unicellular and multicellular organisms.

Question 18

You are given the task of designing an aquatic protist that is a primary producer.It cannot swim on its own,yet must stay in well-lit surface waters.It must be resistant to physical damage from wave action.It should be most similar to a(n)

Accepted Answer

Diatoms are unicellular algae that commonly exist as photosynthetic primary producers in aquatic environments. They have a rigid, silica-based cell wall that provides physical protection from wave action. Additionally, diatoms are typically found in well-lit surface waters, as they require sunlight for photosynthesis. While they cannot swim on their own, they are often carried along by water currents.

Question 19

Which of the following statements concerning protists is true?

Accepted Answer

This is a true statement. All protists have mitochondria, though in some species, they are much reduced and may be known by different names, such as hydrogenosomes or mitosomes.

Question 20

The best evidence for not classifying the slime moulds as fungi comes from slime moulds'

Accepted Answer

The best evidence for not classifying slime moulds as fungi comes from DNA sequences. Recent genetic studies have shown that slime moulds have a closer relationship with amoebas and other protists than with fungi.

Quiz 28: Protists