Question 1

Which algal group is primarily responsible for the formation of underwater forests and can reach lengths up to 100 meters, as seen in the Sargasso Sea?

Accepted Answer

Phaeophyta (Brown algae)

Question 2

The structure labeled 'frustule' in diatoms is primarily composed of which substance?

Accepted Answer

Silica (hydrated silicon dioxide)

Question 3

Which pigment is responsible for the brown coloration in kelp and other brown algae?

Accepted Answer

Fucoxanthin

Question 4

A harmful algal bloom known as 'red tide' is most commonly caused by which group of organisms?

Accepted Answer

Dinoflagellates

Question 5

Which algal group is characterized by the presence of phycobilin pigments and is important in the formation of coral reefs due to its ability to secrete CaCO$$_3$$?

Accepted Answer

Rhodophyta

Question 6

The Irish potato famine was caused by a member of which algal-related group, and what is a distinguishing feature of its cell wall?

Accepted Answer

Oomycota; cell wall contains cellulose

Question 7

Which of the following best describes the evolutionary relationship of the group 'Protista'?

Accepted Answer

Paraphyletic, excluding some descendants of a common ancestor

Question 8

Which algal group stores its food as paramylon and lacks a cell wall, instead having a pellicle protein layer?

Accepted Answer

Euglenophyta (Euglenoids)

Question 9

Which structure forms during late cytokinesis in certain algae and land plants, serving as a scaffold for cell plate assembly?

Accepted Answer

Phragmoplast

Question 10

In the context of algal cell biology, what is the function of a pyrenoid?

Accepted Answer

It enhances the activity of RuBisCO for CO$$_2$$ fixation

Question 11

Which algal group is most closely related to land plants based on genetic studies and the presence of plasmodesmata?

Accepted Answer

Charophyta

Question 12

Diatoms are excellent indicators of water quality because:

Accepted Answer

They are highly diverse and sensitive to environmental changes

Question 13

Which of the following is a distinguishing feature of desmids (Order Desmidiales)?

Accepted Answer

Highly symmetrical semi-cells and reproduction by fission

Question 14

Which pigment combination is found in green algae (Chlorophyta) and is also shared with land plants?

Accepted Answer

Chlorophyll a and b

Question 15

Which algal group is known for its exoskeleton of calcareous plates called coccoliths and is abundant in marine phytoplankton?

Accepted Answer

Haptophyta (Coccolithophores)

Question 16

A student observes a biflagellated, motile, single-celled alga in a freshwater sample. Which genus is most likely being observed?

Accepted Answer

Chlamydomonas

Question 17

Which of the following is NOT a typical storage product for diatoms (Bacillariophyta)?

Accepted Answer

Starch

Question 18

Which algal group is most likely to be found as epiphytes on aquatic plants, forming flat, sprawling discs, and reproducing both sexually and asexually?

Accepted Answer

Coleochaetales (Charophyta)

Question 19

Which of the following statements about the vegetative state of Oomycota is correct?

Accepted Answer

It has diploid nuclei, unlike fungi

Question 20

A scientist is studying an alga with a cup-shaped chloroplast and one to three pyrenoids. Which genus is most likely being studied?

Accepted Answer

Ulva

L 4.1: Algal Protists: Diversity, Structure, and Ecological Roles

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