Question 1

Which of the following groups of eukaryotes are considered most closely related?

Accepted Answer

Red algae and plants are considered most closely related because they both belong to the Archaeplastida group, which is characterized by having a common ancestor that engulfed a cyanobacterium, leading to the development of chloroplasts.

Question 2

Which of the following protist groups move using pseudopodia?

Accepted Answer

Rhizopods, such as amoebas, move using pseudopodia, which are temporary projections of their cytoplasm.

Question 3

In which of the following groups of protists do typical species have a sexual life cycle that includes motile gametes?

Accepted Answer

B

Question 4

Which of the following protist groups contain species that form symbiotic associations with unicellular algae?

Accepted Answer

The answer of Which of the following protist groups contain...

Question 5

Which of the following statements provides evidence supporting the endosymbiotic origin of mitochondria?

Accepted Answer

The answer of Which of the following statements provides evidence...

Question 6

A biologist is asked to examine and describe a newly discovered species from a sample of fresh-water plankton. The organism is a heterotrophic unicell with a single flagellum surrounded by a collar of microvilli. The biologist correctly predicts that this organism has

Accepted Answer

The description of a heterotrophic unicell with a single flagellum surrounded by a collar of microvilli fits the characteristics of choanoflagellates. These organisms often have a basket-like skeleton made of silica strips, which are cemented together and surrounded by a membranous web.

Question 7

You have been asked to identify an organism that is a unicellular, free-living heterotroph. It has a single flagellum and is surrounded by a basket-shaped structure composed of silica strips. You would conclude that the organism is a

Accepted Answer

Choanoflagellates are unicellular, free-living heterotrophs that have a single flagellum surrounded by a unique collar-like structure, which can be described as basket-shaped. This structure is not composed of silica strips, but the description closely matches choanoflagellates more than the other options, which do not fit the description provided.

Question 8

Unicellular amoebae that aggregate to form a migratory colony when their food supply runs short are characteristic of

Accepted Answer

Cellular slime molds, such as those in the genus Dictyostelium, exhibit the unique behavior of living as individual amoeboid cells when food is abundant but aggregating into a multicellular, migratory slug-like form when food becomes scarce. This aggregation allows them to move as a unit to a more favorable location where they can form a fruiting body and disperse spores, potentially giving rise to new amoebae.

Question 9

Which is the correct sequence of stages in the lifecycle of a typical myxomycete?

Accepted Answer

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Question 10

Diplomonads are

Accepted Answer

The answer of Diplomonads are
...

Question 11

A medical laboratory isolates an intestinal parasite responsible for a local epidemic of severe dysentery. The organism is unicellular with a pair of nuclei and multiple flagella. You would expect that this organism would also have

Accepted Answer

The answer of A medical laboratory isolates an intestinal parasite...

Question 12

Parabasalids are a small group of protists involved in parasitic or commensal relationships with animals. Parabasalids are unusual in that

Accepted Answer

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Question 13

Heliozoans are radially symmetrical unicells with intricate siliceous skeletons, found mainly in freshwater plankton. They feed by engulfing food particles that become trapped on the surface of numerous thin ray-like extensions of the cytoplasm that radiate from the surface. Each cytoplasmic extension is made rigid by a central rod of microtubules. Based on this description, Heliozoans would be classified as

Accepted Answer

Heliozoans are classified as actinopods due to their characteristic radial symmetry, intricate siliceous skeletons, and the presence of thin ray-like cytoplasmic extensions that are supported by microtubules, which are used for feeding.

Question 14

Radiolarians are single-celled radially symmetrical protists with elaborate skeletons commonly composed of

Accepted Answer

Radiolarians are known for their intricate and beautiful skeletons made of silica, which is a component of glass. These skeletons can be very detailed and are used in scientific studies, including paleoclimatology.

Question 15

The photosynthetic eukaryotes

Accepted Answer

Photosynthetic eukaryotes share an acquired organelle, the chloroplast, which originated from a common endosymbiotic event involving a cyanobacterium, rather than sharing a common ancestor.

Question 16

The phycobilin pigments, phycocyanin and phycoerythrin, are accessory photosynthetic pigments in the plastids of

Accepted Answer

Phycobilin pigments, such as phycocyanin and phycoerythrin, are characteristic of rhodophytes (red algae), where they serve as accessory pigments to capture light energy for photosynthesis.

Question 17

The photosynthetic pigments found in the plastids of green algae are

Accepted Answer

Green algae primarily contain chlorophyll a, chlorophyll b, and ß-carotene as their photosynthetic pigments, which are crucial for capturing light energy during photosynthesis.

Question 18

An alga is collected from very deep water (150 m). It has a multicellular growth form and non-motile gametes, and therefore is most likely to be a

Accepted Answer

Rhodophytes, or red algae, are known to inhabit deep marine environments due to their ability to efficiently utilize blue light, which penetrates deeper into the water. They are also multicellular and typically have non-motile gametes.

Question 19

Cryptomonads differ from other photosynthetic protists in that they

Accepted Answer

Cryptomonads are unique among photosynthetic protists because they have a second, much-reduced nucleus associated with the chloroplast, known as a nucleomorph. This feature is a result of their chloroplasts being acquired through secondary endosymbiosis, where a eukaryotic algal cell was engulfed by another eukaryotic cell.

Question 20

Chlorophytes and phaeophytes share all of the following characteristics EXCEPT

Accepted Answer

Chlorophytes (green algae) and phaeophytes (brown algae) share several characteristics, but the structure of their motile gametes differs. Chlorophytes typically have two equal or nearly equal flagella that may not fit the description of one smooth and one hairy flagellum, which is more characteristic of some other algae groups.

Quiz 36: The Protists