Chapter 27, Problem 1TYK

Which of the following is a characteristic of protists that is also found in at least one other group?

a. division by binary fission

b. multicellular structures

c. complex developmental stages

d. peptidoglycan cell walls

e. organelles and reproduction by meiosis/mitosis

Summary Introduction

Introduction:

Protists are the diverse organisms on earth which include both microscopic unicellular organisms as well as large multicellular organisms. They have a true nucleus, and thus, they are included in eukaryotes. They can be found in diverse habitats, such as, oceans, ponds, streams, moist soil as well as within the body of the host. Although they possess similarities with other groups, they can be differentiated on the basis of distinct characters, such as, components of the cell wall and lack of collagen.

Answer to Problem 1TYK

Correct answer:

A characteristic of protists that is also found in at least one other group is the presence of organelles and reproduction by meiosis/ mitosis.

Explanation of Solution

Justification/ Explanation for the correct answer:

Option (e) states that organelles and reproduction by meiosis/ mitosis is a characteristic of protists that is also found in at least one other group. Protists contain cytoplasmic organelles, such, as endoplasmic reticulum, mitochondria, Golgi body, and chloroplasts (in some species). Also, they can reproduce by asexual as well as sexual methods. These characteristics of protists are similar to that of eukaryotes, such as, plants and animals. Hence, option (e) is the correct answer.

Explanation for the incorrect answer:

Option (a) states that division by binary fission is a characteristic of protists that is also found in at least one other group. Protists do not reproduce by binary fission in which a parental cell gives rise to two similar daughter cells. Instead, their mode of reproduction is asexual (by mitosis), or sexual (by meiosis and gamete fusion). So, it is an incorrect option.

Option (b) states that multicellular structure is a characteristic of protists that is also found in at least one other group. Most of the protists are unicellular and only some are multicellular. Usually, they lack well-differentiated multicellular structures. They are differentiated from animals by the absence of organs (such as the heart) and are distinct from plants because of the lack of true roots, stem, and leaves. So, it is an incorrect option.

Option (c) states that complex developmental stage is a characteristic of protists that is also found in at least one other group. Protists have characteristics that resemble those of fungi, plants, or animals. However, protists can be differentiated on the basis of the absence of complex developmental stages during growth. So, it is an incorrect option.

Option (d) states that peptidoglycan cell wall is a characteristic of protists that is also found in at least one other group. The layer of supportive protein fibers that is located below the plasma membrane in protists is pellicle. It provides strength as well as flexibility to the cell. The peptidoglycan cell wall is a characteristic of the bacterial cell wall and is not present in protists. So, it is an incorrect option.

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

Conclusion

Therefore, it can be concluded that protists are eukaryotes that contain a pellicle layer for protection. They are distinct from other groups because of the absence of complex developmental stages, lack of binary fission, and the absence of complex multicellular structures.