Chapter 19, Problem 36A

Summary Introduction

Introduction :

The acellular slime molds are also known as plasmodial slime molds. They have cells that are surrounded by a plasma membrane only. The life cycle of acellular slime molds begins with spores. The spores possess a cell wall of cellulose. Spores produce amoeboid cells that lack cell walls. They creep over the surface of the substratum with the help of pseudopodia.

Answer to Problem 36A

Correct answer :

Option (D) cilia.

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) cilia. An amoeboid form of cellular slime mold moves with the help of flagella. Once they come in contact with the favorable surface where water is present, they retract flagella. The retraction of flagella is followed by the formation of pseudopodia. Pseudopodia allow these cells to move over the surface by changing its shape.

Explanation for incorrect answer :

Option (A) chromosomes. All the acellular smile molds are eukaryotes and possess characters of both animals and fungi. They possess nuclei inside which the genetic material is present in the form of chromosomes. 

Option (B) spores. The plasmodium bears sporangium that bursts to release spores. These spores germinate to form myxamoeba that fuse in pairs to form a zygote. The zygote forms plasmodium and the whole cycle repeats. Thus, we can say that spores are produced during the life cycle of acellular slime molds.

Option (C) separate cells. Acellular slime molds possess separate cells except for a stage in their life cycle known as plasmodium. This stage is characterized by the presence of a wall-less mass of multinucleate protoplasm covered by slime.