Chapter 26, Problem 1TYU

Test Your Understanding

1. Which of the following is not true of the protists? (a) they are unicellular, colonial, coenocytic, or simple multicellular organisms (b) their cilia and flagella have a 9 + 2 arrangement of microtubules (c) they are prokaryotic, as bacteria and archaea are (d) some are free-living, and some are endosymbionts (e) most are aquatic and live in the ocean or in freshwater ponds

Summary Introduction

Introduction: Protist is a microscopic organism that falls in the kingdom “Protista”. These have been classified into various categories depending upon their mode of nutrition. They can reproduce both sexually and asexually.

Answer to Problem 1TYU

Correct answer: Protist are not prokaryotic, they are eukaryotic organisms. This statement is not true of the protists. Hence, the correct answer is option (c).

Explanation of Solution

Reason for correct answer:

Protists are eukaryotic organisms with a well-defined nucleus. They have a nuclear membrane that encloses the genetic material. Protists have cilia and flagella with a 9 + 2 arrangement of microtubules. They live in an aquatic habitat. Some of them are free-living, while others are endosymbionts.

Thus, the statement that they are prokaryotic in nature is not true.

Option (c) is given as “they are prokaryotic, as bacteria and archaea are”

Protists are eukaryotic organisms. They are not prokaryotes. Hence, the correct answer is option (c).

Reasons for incorrect answer:

Option (a) is given as, “they are unicellular, colonial, coenocytic, or simple multicellular organisms”.

Protist is a unicellular, colonial, coenocytic or simple multicellular organism. This statement about protists is true. Hence, option (a) is incorrect.

Option (b) is given as “their cilia and flagella have a 9 + 2 arrangement of microtubules”.

Protists have cilia and flagella with a 9 + 2 arrangement of microtubules. This statement about protists is true. Hence, option (b) is incorrect.

Option (d) is given as, “some are free-living, and some are endosymbionts”.

There are different types of protist depending upon their mode of nutrition. Some are free living while others endosymbionts. This statement about protists is true. Hence, option (d) is incorrect.

Option (e) is given as, “most are aquatic and live in the ocean or in freshwater ponds”.

Protists are an aquatic organism. They live in water bodies. This statement about protists is true. Hence, option (e) is incorrect.

Hence, the options (a), (b), (d), and (e) are incorrect.

Conclusion

Protists are eukaryotic, unicellular, colonial, coenocytic organisms.